UNITED STATESSECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORTPursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 30, 2017

Opexa Therapeutics, Inc.(Exact name of registrant as specified in its charter)

Texas 001-33004 76-0333165

(State or other jurisdictionof incorporation)

(CommissionFile Number)

(IRS EmployerIdentification No.)

2635 Technology Forest Blvd.The Woodlands, Texas 77381

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (281) 272-9331

ChecktheappropriateboxbelowiftheForm8-Kfilingisintendedtosimultaneouslysatisfythefilingobligationsoftheregistrantunderanyofthefollowingprovisions:

☒ WrittencommunicationspursuanttoRule425undertheSecuritiesAct(17CFR230.425)

☐ SolicitingmaterialpursuanttoRule14a-12undertheExchangeAct(17CFR240.14a-12)

☐ Pre-commencementcommunicationspursuanttoRule14d-2(b)undertheExchangeAct(17CFR240.14d-2(b))

☐ Pre-commencementcommunicationspursuanttoRule13e-4(c)undertheExchangeAct(17CFR240.13e-4(c))

IndicatebycheckmarkwhethertheregistrantisanemerginggrowthcompanyasdefinedinRule405oftheSecuritiesActof1933(§230.405ofthischapter)orRule12b-2oftheSecuritiesExchangeActof1934(§240.12b-2ofthischapter).

Emerginggrowthcompany☐

Ifanemerginggrowthcompany,indicatebycheckmarkiftheregistranthaselectednottousetheextendedtransitionperiodforcomplyingwithanyneworrevisedfinancialaccountingstandardsprovidedpursuanttoSection13(a)oftheExchangeAct.☐

Item 1.01 Entry into a Material Definitive Agreement.

AgreementandPlanofMerger

OnJune30,2017,OpexaTherapeutics,Inc.,aTexascorporation(“Opexa ”),OpexaMergerSub,Inc.,aDelawarecorporationandawholly-ownedsubsidiaryofOpexa(“Merger Sub ”),andAcerTherapeuticsInc.,aDelawarecorporation(“Acer ”),enteredintoanAgreementandPlanofMergerandReorganization(the“Merger Agreement ”),pursuanttowhich,amongotherthings,subjecttothesatisfactionorwaiveroftheconditionssetforthintheMergerAgreement,MergerSubwillmergewithandintoAcer,withAcerbecomingawholly-ownedsubsidiaryofOpexaandthesurvivingcorporationofthemerger(the“Merger ”).TheMergerisintendedtoqualifyforfederalincometaxpurposesasatax-freereorganizationundertheprovisionsofSection368(a)oftheInternalRevenueCodeof1986,asamended(the“Internal Revenue Code ”).

SubjecttothetermsandconditionsoftheMergerAgreement,attheclosingoftheMerger,eachoutstandingshareofAcercommonstockwillbeconvertedintotherighttoreceiveapproximatelyoneshareofcommonstockofOpexa,whichamountissubjecttoadjustmentpriortoclosingoftheMergerupontheoccurrenceofspecifiedevents,includingtoaccountforanyadditionalsharesthatAcermayissuebeforeclosingandforOpexa’snetcashbalanceatclosing.NofractionalshareswillbeissuedinconnectionwiththeMergerandOpexawillpaycashinlieuofanysuchfractionalshares.ImmediatelyfollowingtheeffectivetimeoftheMerger,(a)currentOpexashareholdersareexpectedtoownapproximately11.2%ofthecombinedcompany,(b)currentAcershareholdersareexpectedtoownapproximately63.8%ofthecombinedcompany(excludinganysharesissuedtocurrentshareholdersintheconcurrentfinancing),and(c)theinvestorsparticipatingintheconcurrentfinancingareexpectedtoownapproximately25%ofthecombinedcompany(excludinganysharespreviouslyheldbyinvestorsintheconcurrentfinancing),ineachcasecalculatedonapro-formabasisaftergivingeffectto(i)theissuanceofsharesofcommonstockbyAcerimmediatelypriortotheeffectivetimeoftheMergerpursuanttothetermsofthesubscriptionagreement(asdiscussedbelow)and(ii)theMerger.

ConsummationoftheMergerissubjecttocertainclosingconditions,including,amongotherthings,approvalbytherespectiveshareholdersofOpexaandAcer.TheMergerAgreementcontainsspecifiedterminationrightsforbothOpexaandAcer,andfurtherprovidesthat,uponterminationoftheMergerAgreementunderspecifiedcircumstances,OpexamaybeobligatedtopayAceraterminationfeeof$250,000,andAcermaybeobligatedtopayOpexaaterminationfeeof$1,000,000,plus,underspecifiedcircumstances,reimbursementforvariousexpensesincurredinconnectionwiththeMerger.

AttheeffectivetimeoftheMerger,theBoardofDirectorsofOpexaisexpectedtoconsistofsevenmembersdesignatedbyAcer.

InconnectionwiththeMerger,Opexawillseekshareholderapprovaltoadoptamendmentstoitscertificateofformationto:(a)effectareversesplitofOpexa’scommonstockand(b)changeOpexa’snametoAcerTherapeuticsInc.,ineachcasesubjecttotheconsummationoftheMerger.

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AlsoinconnectionwiththeMerger,Opexawill,attheeffectivetimeoftheMerger,assumetheoutstandingstockoptionsofAcersubjecttothetermsoftheMergerAgreement.AlloutstandingstockoptionsofOpexawillbecancelledandextinguishedattheeffectivetimeoftheMergerwithoutanyrighttoreceiveanyconsideration.

InaccordancewiththetermsoftheMergerAgreement,(a)theofficersanddirectorsofOpexahaveeachenteredintoasupportagreementwithAcer(the“Opexa Support Agreements ”),and(b)theofficers,directorsandcertainaffiliatedshareholdersofAcerowningorcontrolling,intheaggregate,amajorityofAcer’soutstandingcapitalstockhaveeachenteredintoasupportagreementwithOpexa(the“Acer Support Agreements ,”andtogetherwiththeOpexaSupportAgreements,the“Support Agreements ”).TheSupportAgreementsplacecertainrestrictionsonthetransferofthesharesofcapitalstockofOpexaandAcerheldbytherespectivesignatoriesandincludecovenantsastothevotingofsuchsharesinfavorofapprovingthetransactionscontemplatedbytheMergerAgreementandagainsttakingspecifiedactionsthatcouldadverselyaffecttheconsummationoftheMerger.

PriortoAcer’sentryintotheMergerAgreement,certainthirdparties,includingcertainexistingshareholdersofAcer,enteredintoasubscriptionagreementwithAceronJune30,2017pursuanttowhichsuchpartieshaveagreed,subjecttothetermsandconditionsofsuchagreement,topurchase,immediatelypriortotheconsummationoftheMerger,sharesofAcer’scommonstockforanaggregatepurchasepriceofapproximately$15.7million.Theconsummationofthetransactionscontemplatedbysuchagreementisconditionedupon,amongotheritems,thesatisfactionorwaiveroftheclosingconditionssetforthintheMergerAgreement.

TheprecedingsummarydoesnotpurporttobecompleteandisqualifiedinitsentiretybyreferencetotheMergerAgreement,theformofOpexaSupportAgreementandtheformofAcerSupportAgreement,whicharefiledasExhibits2.1,2.2and2.3,respectively,tothisCurrentReportonForm8-Kandwhichareincorporatedhereinbyreference.

AdditionalInformationabouttheMergerandWheretoFindIt

InconnectionwiththeMerger,OpexaandAcerintendtofilerelevantmaterialswiththeSecuritiesandExchangeCommission(the“SEC ”),includingaregistrationstatementonFormS-4thatwillcontainaproxystatement/prospectus/informationstatement.InvestorsandsecurityholdersofOpexaandAcerareurgedtoreadthesematerialswhentheybecomeavailablebecausetheywillcontainimportantinformationaboutOpexa,AcerandtheMerger.Theproxystatement/prospectus/informationstatementandotherrelevantmaterials(whentheybecomeavailable),andanyotherdocumentsfiledbyOpexawiththeSEC,maybeobtainedfreeofchargeattheSECwebsiteatwww.sec.gov .Inaddition,investorsandsecurityholdersmayobtainfreecopiesofthedocumentsfiledwiththeSECbyOpexabydirectingawrittenrequestto:OpexaTherapeutics,Inc.,2635TechnologyForestBlvd.,TheWoodlands,TX77381,Attention:InvestorRelations.Investorsandsecurityholdersareurgedtoreadtheproxystatement/prospectus/informationstatementandtheotherrelevantmaterialswhentheybecomeavailablebeforemakinganyvotingorinvestmentdecisionwithrespecttotheMerger.

This communication shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shallthere be any sale of securities in

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any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction.No offering of securities in connection with the Merger shall be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Actof 1933, as amended.

ParticipantsintheSolicitation

OpexaandAcerandtheirrespectivedirectorsandexecutiveofficersmaybedeemedtobeparticipantsinthesolicitationofproxiesfromtheshareholdersofOpexainconnectionwiththeMerger.InformationregardingthespecialinterestsofthesedirectorsandexecutiveofficersintheMergerwillbeincludedintheproxystatement/prospectus/informationstatementreferredtoabove.AdditionalinformationregardingthedirectorsandexecutiveofficersofOpexaisalsoincludedinOpexa’sAnnualReportonForm10-KfortheyearendedDecember31,2016andtheproxystatementforOpexa’s2016annualmeetingofshareholders.ThesedocumentsareavailablefreeofchargeattheSEC’swebsite(www.sec.gov )andfromInvestorRelationsatOpexaattheaddresssetforthabove.

Item 8.01 Other Events.

OnJuly3,2017,OpexaissuedajointpressreleasewithAcerrelatingtotheMergerAgreement.AcopyofthejointpressreleaseisattachedheretoasExhibit99.1andisincorporatedbyreferenceherein.

Forward-LookingStatements

Certain statements either contained in or incorporated by reference into this document, other than purely historical information, including estimates,projections and statements relating to Opexa’s business plans, objectives and expected operating results, and the assumptions upon which those statements arebased, are “forward-looking statements.” All statements, other than statements of historical facts, included in or incorporated by reference into this documentregarding strategy, future operations, future financial position, future revenue, projected expenses, prospects, plans and objectives of management are forward-looking statements. Examples of such statements include, but are not limited to, statements relating to the structure, timing and completion of the proposed mergeror financing; Opexa’s continued listing on the NASDAQ Capital Market until closing of the proposed merger; the combined company’s listing on the NASDAQCapital Market after closing of the proposed merger; expectations regarding the capitalization, resources and ownership structure of the combined company; thepotential for EDSIVO™ (celiprolol) and ACER-001 to target diseases; the adequacy of the combined company’s capital to support its future operations and itsability to successfully initiate and complete clinical trials; the nature, strategy and focus of the combined company; the development and commercial potential ofany product candidates of the combined company; the executive and board structure of the combined company; and expectations regarding voting by Opexa’s andAcer’s shareholders. Opexa and/or Acer may not actually achieve the plans, carry out the intentions or meet the expectations or projections disclosed in theforward-looking statements and you should not place undue reliance on these forward-looking statements. Such statements are based on management’s currentexpectations and involve risks and uncertainties. Actual results and performance could differ materially from

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those projected in the forward-looking statements as a result of many factors, including, without limitation, risks and uncertainties associated with shareholderapproval of and the ability to consummate the proposed merger through the process being conducted by Opexa and Acer, the ability to project future cashutilization and reserves needed for contingent future liabilities and business operations, the availability of sufficient resources of the combined company to meet itsbusiness objectives and operational requirements, the fact that the results of earlier studies and trials may not be predictive of future clinical trial results, theprotection and market exclusivity provided by Acer’s intellectual property, risks related to the drug discovery and the regulatory approval process and the impactof competitive products and technological changes. Opexa and Acer each disclaims any intent or obligation to update these forward-looking statements to reflectevents or circumstances that exist after the date on which they were made.

Item 9.01 Financial Statements and Exhibits.

ReferenceismadetotheExhibitIndexincludedwiththisCurrentReportonForm8-K.

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SIGNATURES

PursuanttotherequirementsoftheSecuritiesExchangeActof1934,theRegistranthasdulycausedthisreporttobesignedonitsbehalfbytheundersignedhereuntodulyauthorized.

Opexa Therapeutics, Inc.

Dated:July3,2017 By: /s/NeilK.Warma NeilK.Warma President,ChiefExecutiveOfficerandActingChiefFinancialOfficer

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EXHIBIT INDEXExhibitNo. Description

2.1*

AgreementandPlanofMergerandReorganization,datedasofJune30,2017,byandamongOpexaTherapeutics,Inc.,OpexaMergerSub,Inc.andAcerTherapeuticsInc.

2.2 FormofSupportAgreement,byandbetweenAcerTherapeuticsInc.anddirectorsandofficersofOpexaTherapeutics,Inc.

2.3 FormofSupportAgreement,byandbetweenOpexaTherapeutics,Inc.andcertaindirectors,officersandshareholdersofAcerTherapeuticsInc.

99.1 Pressrelease,datedJuly3,2017.* The schedules and exhibits to the Merger Agreement have been omitted pursuant to Item 601(b)(2) of Regulation S-K. A copy of any omitted schedule and/or

exhibit will be furnished to the Securities and Exchange Commission upon request.

Exhibit 2.1

AGREEMENT AND PLAN OF MERGER

AND REORGANIZATION

Among

OPEXA THERAPEUTICS, INC.

OPEXA MERGER SUB, INC., and

ACER THERAPEUTICS INC.

Dated as of June 30, 2017

Table of ContentsARTICLE1DESCRIPTIONOFTRANSACTION 2

1.1 StructureoftheMerger 21.2 EffectsoftheMerger 21.3 Closing;EffectiveTime 21.4 CertificateofIncorporationandBylaws;DirectorsandOfficers 31.5 ConversionofSharesandAssumptionofOptions 31.6 CalculationofNetCash 51.7 ClosingofAcer’sTransferBooks 61.8 SurrenderofCertificates 61.9 AppraisalRights 81.10 FurtherAction 81.11 TaxConsequences 91.12 Certificates 9

ARTICLE2REPRESENTATIONSANDWARRANTIESOFACER 9

2.1 Subsidiaries;DueOrganization;OrganizationalDocuments 102.2 Authority;VoteRequired 102.3 Non-Contravention;Consents 112.4 Capitalization 112.5 FinancialStatements 122.6 AbsenceofChanges 132.7 TitletoAssets 132.8 RealProperty;Leaseholds 132.9 IntellectualProperty 142.10 MaterialContracts 162.11 UndisclosedLiabilities 182.12 Compliance;Permits;Restrictions 182.13 TaxMatters 202.14 EmployeeandLaborMatters;BenefitPlans 222.15 EnvironmentalMatters 262.16 Insurance 262.17 LegalProceedings;Orders 272.18 InapplicabilityofAnti-TakeoverStatutes 272.19 NoFinancialAdvisor 272.20 SubscriptionAgreement 272.21 Disclosure 282.22 ExclusivityofRepresentations;Reliance 28

ARTICLE3REPRESENTATIONSANDWARRANTIESOFOPEXAANDMERGERSUB 28

3.1 Subsidiaries;DueOrganization;OrganizationalDocuments 293.2 Authority;VoteRequired 29

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3.3 Non-Contravention;Consents 313.4 Capitalization 313.5 SECFilings;FinancialStatements 333.6 AbsenceofChanges 353.7 TitletoAssets 353.8 RealProperty;Leaseholds 353.9 IntellectualProperty 363.10 MaterialContracts 383.11 UndisclosedLiabilities 403.12 Compliance;Permits;Restrictions 403.13 TaxMatters 413.14 EmployeeandLaborMatters;BenefitPlans 433.15 EnvironmentalMatters 483.16 Insurance 493.17 LegalProceedings;Orders 493.18 InapplicabilityofAnti-TakeoverStatutes 503.19 NoFinancialAdvisor 503.20 Disclosure 503.21 BankAccounts;Deposits 503.22 TransactionswithAffiliates 513.23 ValidIssuance 513.24 CodeofEthics 513.25 ShellCompanyStatus 513.26 Anti-CorruptionMatters 513.27 ExclusivityofRepresentations;Reliance 52

ARTICLE4CERTAINCOVENANTSOFTHEPARTIES 52

4.1 AccessandInvestigation 524.2 OperationofOpexa’sBusiness 534.3 OperationofAcer’sBusiness 554.4 NotificationofCertainMatters 574.5 NoSolicitation 58

ARTICLE5ADDITIONALAGREEMENTSOFTHEPARTIES 60

5.1 RegistrationStatement;ProxyStatement/Prospectus/InformationStatement 605.2 AcerStockholderWrittenConsent 615.3 OpexaShareholders’Meeting 635.4 RegulatoryApprovals 655.5 AcerOptions 665.6 OpexaEmployeeandBenefitsMatters;OpexaOptions 675.7 IndemnificationofOfficersandDirectors 695.8 AdditionalAgreements 705.9 Disclosure 705.10 Listing 70

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5.11 TaxMatters 715.12 Legends 715.13 DirectorsandOfficers 715.14 Section16Matters 725.15 TakeoverStatutes 725.16 PreferredStock 725.17 TerminationofCertainAgreementsandRights 725.18 NetCash 72

ARTICLE6CONDITIONSPRECEDENTTOOBLIGATIONSOFEACHPARTY 72

6.1 EffectivenessofRegistrationStatement 726.2 NoRestraints 726.3 StockholderApproval 736.4 RegulatoryMatters 736.5 Listing 736.6 NetCashCalculation 73

ARTICLE7ADDITIONALCONDITIONSPRECEDENTTOOBLIGATIONSOFOPEXAANDMERGERSUB 73

7.1 AccuracyofRepresentations 737.2 PerformanceofCovenants 747.3 NoAcerMaterialAdverseEffect 747.4 PreferredStockConversion 747.5 TerminationofInvestorAgreements 747.6 AcerDebtConversion 747.7 AcerPre-ClosingFinancing 747.8 Documents 74

ARTICLE8ADDITIONALCONDITIONSPRECEDENTTOOBLIGATIONSOFACER 75

8.1 AccuracyofRepresentations 758.2 PerformanceofCovenants 758.3 NoOpexaMaterialAdverseEffect 758.4 TerminationofContracts 758.5 BoardofDirectorsandOfficers 758.6 Sarbanes-OxleyCertifications 768.7 NetCashThreshold 768.8 ShellCompanyStatus 768.9 SatisfactionofLiabilities 768.10 AmendmenttoCertificateofFormation 768.11 Bylaws 768.12 Documents 76

ARTICLE9TERMINATION 77

9.1 Termination 77

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9.2 EffectofTermination 799.3 Expenses;TerminationFees 79

ARTICLE10MISCELLANEOUSPROVISIONS 82

10.1 Non-SurvivalofRepresentationsandWarranties 8210.2 Amendment 8210.3 Waiver 8210.4 EntireAgreement;Counterparts;ExchangesbyFacsimile 8310.5 ApplicableLaw;Jurisdiction 8310.6 Attorneys’Fees 8310.7 Assignability;NoThirdPartyBeneficiaries 8310.8 Notices 8310.9 Severability 8410.10 OtherRemedies;SpecificPerformance 8510.11 Construction 85

Schedules:

OpexaDisclosureScheduleAcerDisclosureScheduleScheduleA PersonsExecutingAcerStockholderSupportAgreementsScheduleB PersonsExecutingOpexaShareholderSupportAgreementsSchedule5.6(a)(ii) TerminatedOpexaAssociatePaymentsSchedule5.6(c) OpexaBenefitPlansSchedule5.13 OpexaOfficersandDirectorsattheEffectiveTimeSchedule5.17 InvestorAgreementsSchedule8.4 TerminatedContracts

Exhibits:

ExhibitA DefinitionsExhibitB FormofAcerStockholderSupportAgreementExhibitC FormofOpexaShareholderSupportAgreementExhibitD SubscriptionAgreementExhibitE SurvivingCorporationCertificateofIncorporation

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AGREEMENT AND PLAN OF MERGER AND REORGANIZATION

THIS AGREEMENT AND PLAN OF MERGER AND REORGANIZATION (this“Agreement”)ismadeandenteredintoasofJune30,2017,byandamongOpexa Therapeutics, Inc., aTexascorporation(“Opexa”),Opexa Merger Sub, Inc. ,aDelawarecorporation(“MergerSub”),andAcer TherapeuticsInc. ,aDelawarecorporation(“Acer”).CertaincapitalizedtermsusedinthisAgreementaredefinedinExhibitA.

RECITALS

A.OpexaandAcerintendtoeffectamergerofMergerSubintoAcer(the“Merger”)inaccordancewiththisAgreementandtheDGCL.UponconsummationoftheMerger,MergerSubwillceasetoexist,andAcerwillbecomeawholly-ownedsubsidiaryofOpexa.

B.ThePartiesintend,byapprovingresolutionsauthorizingthisAgreement,toadoptthisAgreementasaplanofreorganizationwithinthemeaningofSection368(a)oftheCode,andtocausetheMergertoqualifyasareorganizationundertheprovisionsofSection368(a)oftheCodeandtheTreasuryRegulationspromulgatedthereunder.

C.TheOpexaBoardofDirectors(i)hasdeterminedthattheMergerisfairto,andinthebestinterestsof,OpexaandtheOpexaShareholders,(ii)hasdeemedadvisableandapprovedthisAgreement,theMerger,theOpexaShareholderMatters,andotheractionscontemplatedbythisAgreement;and(iii)hasdeterminedtorecommendthattheOpexaShareholdersvotetoapprovetheOpexaShareholderMatters.

D.TheBoardofDirectorsofMergerSub(i)hasdeterminedthattheMergerisfairto,andinthebestinterestsof,MergerSubanditssolestockholder,(ii)hasdeemedadvisableandapprovedthisAgreement,theMerger,andtheapplicableContemplatedTransactions,and(iii)hasdeterminedtorecommendthatthestockholderofMergerSubvotetoadoptthisAgreementandtherebyapprovetheMergerandtheapplicableContemplatedTransactions.

E.TheAcerBoardofDirectors(i)hasdeterminedthattheMergerisadvisableandfairto,andinthebestinterestsof,AcerandtheAcerStockholders,(ii)hasdeemedadvisableandapprovedtheAcerStockholderMattersandotheractionscontemplatedbythisAgreement,and(iii)hasdeterminedtorecommendthattheAcerStockholdersvotetoapprovetheAcerStockholderMatters.

F.InordertoinduceOpexatoenterintothisAgreementandtocausetheMergertobeconsummated,theofficersanddirectorsofAcerandtheAcerStockholders,ineachcase,listedonScheduleAheretoareexecutingconcurrentlywiththeexecutionanddeliveryofthisAgreementsupportagreementsinfavorofOpexaintheformsubstantiallyattachedheretoasExhibitB(the“AcerStockholderSupportAgreements”).

G.InordertoinduceAcertoenterintothisAgreementandtocausetheMergertobeconsummated,theofficersanddirectorsofOpexaandsuchpersons’respectiveAffiliates,ineachcase,listedonScheduleBheretoareexecutingsupportagreementsinfavorofAcerconcurrentlywiththeexecutionanddeliveryofthisAgreementintheformsubstantiallyattachedheretoasExhibitC(the“OpexaShareholderSupportAgreements”).

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H.Itisexpectedthatwithinfive(5)BusinessDaysaftertheFormS-4RegistrationStatementisdeclaredeffectivebytheSECundertheSecuritiesAct,AcerwilldelivertheAcerStockholderWrittenConsent.

I.ImmediatelypriortotheexecutionanddeliveryofthisAgreement,certaininvestorshaveexecutedaSubscriptionAgreementsubstantiallyintheformattachedheretoasExhibitDamongAcerandthePersonsnamedtherein,pursuanttowhichsuchPersonshaveagreedtopurchasethenumberofsharesofAcerCapitalStocksetforththereinpriortotheClosinginconnectionwiththeAcerPre-ClosingFinancing(the“SubscriptionAgreement”).

J.AcermayenterintotheSubscriptionAgreementafterthedatehereofwithadditionalinvestorsinconnectionwiththeAcerPre-ClosingFinancing,providedthatsuchadditionalPurchasersshallbelimitedtooneorafewaccreditedinvestors(andtheiraccreditedAffiliates)withwhichAcerwasinsubstantivediscussionspriortothedatehereof.

AGREEMENT

ThepartiestothisAgreement,intendingtobelegallybound,agreeasfollows:

ARTICLE 1

DESCRIPTION OF TRANSACTION

1.1 Structure of the Merger .UponthetermsandsubjecttotheconditionssetforthinthisAgreementandinaccordancewiththeDGCL,attheEffectiveTime,(a)MergerSubshallbemergedwithandintoAcer,and(b)theseparateexistenceofMergerSubshallceaseandAcerwillcontinueitscorporateexistenceundertheDGCLasthesurvivingcorporationintheMerger(the“SurvivingCorporation”).

1.2 Effects of the Merger .TheMergershallhavetheeffectssetforthinthisAgreementandintheapplicableprovisionsoftheDGCL.AsaresultoftheMerger,Acerwillbecomeawholly-ownedsubsidiaryofOpexa.

1.3 Closing; Effective Time .UnlessthisAgreementisearlierterminatedpursuanttotheprovisionsofSection9.1,andsubjecttothesatisfactionorwaiveroftheconditionssetforthinArticle6,Article7andArticle8,theclosingoftheMerger(the“Closing”)shalltakeplaceattheofficesofFoleyHoagLLP,155SeaportBoulevard,Boston,Massachusetts02210,aspromptlyaspracticable(butinnoeventlaterthanthesecond(2nd)BusinessDayfollowingthesatisfactionorwaiverofthelasttobesatisfiedorwaivedoftheconditionssetforthinArticle6,Article7andArticle8,otherthanthoseconditionsthatbytheirnaturearetobesatisfiedattheClosing,butsubjecttothesatisfactionorwaiverofeachofsuchconditions),oratsuchothertime,dateandplaceasOpexaandAcermaymutuallyagreeinwriting;provided, however ,thatifAcerisnotpreparedtoclosetheAcerPre-ClosingFinancingatsuchtime,Acerhastheright,initssolediscretiontodelaytheClosingforuptoten(10)BusinessDays.ThedateonwhichtheClosingactuallytakesplaceisreferredtoasthe“ClosingDate. ”AttheClosing,thePartiesheretoshallcauseacertificateofmerger(the“CertificateofMerger”)tobeexecuted,acknowledgedandfiledwiththeSecretaryofStateoftheStateofDelawareinaccordancewiththeapplicablerequirementsoftheDGCLandshallmakeallotherfilingsorrecordingsrequired

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undertheDGCL.TheMergerwillbecomeeffectiveatsuchtimeastheCertificateofMergerhasbeendulyfiledwiththeSecretaryofStateoftheStateofDelawareoratsuchlatertimeasmaybespecifiedinsuchCertificateofMergerwiththeconsentofOpexaandAcer(thetimeasofwhichtheMergerbecomeseffectivebeingreferredtoasthe“EffectiveTime”).

1.4 Certificate of Incorporation and Bylaws; Directors and Officers .AttheEffectiveTime:

(a) thecertificateofincorporationoftheSurvivingCorporationshallbeamendedandrestatedinitsentiretytoreadassetforthinExhibitEuntilthereafteramendedasprovidedbytheDGCLandsuchcertificateofincorporation;

(b) thecertificateofformationofOpexashallbethecertificateofformationofOpexaimmediatelypriortotheEffectiveTime,untilthereafteramendedasprovidedbytheTBOCandsuchcertificateofformation;provided ,however ,thatattheEffectiveTime,Opexashallfileoneormoreamendmentstoitscertificateofformation,totheextentapprovedbytheholdersofOpexaCommonStockascontemplatedbySection5.3,to(i)changethenameofOpexato“AcerTherapeuticsInc.,”and(ii)effecttheNASDAQReverseSplit,totheextentrequestedbyAcerpriortothefilingwiththeSECoftheProxyStatement/Prospectus/InformationStatement;

(c) thebylawsoftheSurvivingCorporationshallbeamendedandrestatedintheirentiretytoreadidenticallytothebylawsofMergerSubasineffectimmediatelypriortotheEffectiveTime,untilthereafteramendedinaccordancewiththetermsofsuchbylaws,thecertificateofincorporationoftheSurvivingCorporationandtheDGCL;

(d) thebylawsofOpexashallbethebylawsofOpexaimmediatelypriortotheEffectiveTime;provided, however ,thateffectiveattheEffectiveTime,Opexashallamenditsbylaws,toreplaceallreferencestoOpexa’snamewith“AcerTherapeuticsInc.”;

(e) thedirectorsandofficersofOpexa,eachtoholdofficeinaccordancewiththecertificateofformationandbylawsofOpexa,shallbeassetforthinSection5.13;and

(f) thedirectorsandofficersoftheSurvivingCorporation,eachtoholdofficeinaccordancewiththecertificateofincorporationandbylawsoftheSurvivingCorporation,shallbethedirectorsandofficersofOpexaassetforthinSection5.13,aftergivingeffecttotheprovisionsofSection5.13.

1.5 Conversion of Shares and Assumption of Options.

(a) AttheEffectiveTime,byvirtueoftheMergerandwithoutanyfurtheractiononthepartofOpexa,MergerSub,AceroranyAcerStockholder:

(i) eachshareofAcerCommonStockorAcerPreferredStockheldastreasurystockorheldorownedbyAcer,Opexa,orMergerSub,immediatelypriortotheEffectiveTimeshallbecanceledandretiredandshallceasetoexist,andnoconsiderationshallbedeliveredinexchangetherefor;and

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(ii) subjecttoSection1.5(c),eachshareofAcerCommonStock(includinganysharesofAcerCommonStockissuedpursuanttotheAcerPre-ClosingFinancing)outstandingimmediatelypriortotheEffectiveTime(excludingsharestobecanceledpursuanttoSection1.5(a)(i)andDissentingShares,andaftergivingeffecttothePreferredStockConversion)shallbeconvertedsolelyintotherighttoreceiveanumberofsharesofOpexaCommonStockequaltotheExchangeRatio(theaggregatenumberofsharesofOpexaCommonStockthusissued,the“MergerConsideration”).

(b) IfanysharesofAcerCommonStockoutstandingimmediatelypriortotheEffectiveTimeareunvestedoraresubjecttoarepurchaseoptionortheriskofforfeitureunderanyapplicablerestrictedstockpurchaseagreementorotheragreementwithAcer,thenthesharesofOpexaCommonStockissuedinexchangeforsuchsharesofAcerCommonStockwilltothesameextentbeunvestedandsubjecttothesamerepurchaseoptionorriskofforfeiture,andthebookentrysharesofOpexaCommonStockshallaccordinglybemarkedwithappropriatelegends.Acershalltakeallactionsthatmaybenecessarytoensurethat,fromandaftertheEffectiveTime,Opexaisentitledtoexerciseanysuchrepurchaseoptionorotherrightsetforthinanysuchrestrictedstockpurchaseagreementorotheragreement.

(c) NofractionalsharesofOpexaCommonStockshallbeissuedinconnectionwiththeMerger,andnocertificatesorscripforanysuchfractionalsharesshallbeissued.AnyholderofAcerCommonStockwhowouldotherwisebeentitledtoreceiveafractionofashareofOpexaCommonStock(afteraggregatingallfractionalsharesofOpexaCommonStockissuabletosuchholder)shall,inlieuofsuchfractionofashareanduponsurrenderbysuchholderofaletteroftransmittalinaccordancewithSection1.8andaccompanyingdocumentsasrequiredtherein,bepaidincashthedollaramount(roundedtothenearestwholecent),withoutinterest,determinedbymultiplyingsuchfractionbytheclosingpriceofashareofOpexaCommonStockonTheNASDAQCapitalMarket(orsuchotherNASDAQmarketonwhichtheOpexaCommonStockthentrades)onthedatetheMergerbecomeseffective.

(d) AllAcerOptionsoutstandingimmediatelypriortotheEffectiveTimeunderthe2013PlanshallbeassumedbyOpexaandconvertedintooptionstopurchaseOpexaCommonStock,inaccordancewithSection5.5.

(e) EachshareofCommonStock,$0.0001parvaluepershare,ofMergerSubissuedandoutstandingimmediatelypriortotheEffectiveTimeshallbeconvertedintoandexchangedforonevalidlyissued,fullypaidandnonassessableshareofCommonStock,$0.0001parvaluepershare,oftheSurvivingCorporation.EachstockcertificateofMergerSubevidencingownershipofanysuchsharesshall,asoftheEffectiveTime,evidenceownershipofsuchsharesofCommonStockoftheSurvivingCorporation.

(f) If,betweenthetimeofcalculatingtheExchangeRatioandtheEffectiveTime,theoutstandingsharesofAcerCapitalStockorOpexaCommonStockhavebeenchangedinto,orexchangedfor,adifferentnumberofsharesoradifferentclass,byreasonofanystockdividend,subdivision,reclassification,recapitalization,split(includingtheNASDAQReverseSplittotheextentsuchsplithasnotpreviouslybeentakenintoaccountincalculatingtheExchangeRatio),combinationorexchangeofshares,theExchangeRatioshallbe

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correspondinglyadjustedtoprovidetheholdersofAcerCommonStockandAcerOptionsthesameeconomiceffectascontemplatedbythisAgreementpriortosuchevent.

1.6 Calculation of Net Cash.

(a) ForthepurposesofthisAgreement,the“DeterminationDate”shallbethedatethatisten(10)calendardayspriortotheanticipateddateforClosing(the“AnticipatedClosingDate”),asagreeduponbyOpexaandAceratleastten(10)calendardayspriortotheOpexaShareholders’Meeting.OnorpriortotheDeterminationDate,OpexashallprovideAcerwithalistofallLiabilitiesofOpexaasoftheDeterminationDatethatareindividuallyinexcessof$10,000orinexcessof$25,000intheaggregate,whichhadnotpreviouslybeendisclosedtoAcerintheOpexaDisclosureSchedule.Withinfive(5)calendardaysfollowingtheDeterminationDate,OpexashalldelivertoAceraschedule(the“NetCashSchedule”)settingforth,inreasonabledetail,Opexa’sgoodfaith,estimatedcalculationofNetCash(the“NetCashCalculation”)asoftheAnticipatedClosingDatepreparedandcertifiedbyOpexa’sChiefFinancialOfficer(orifthereisnoChiefFinancialOfficer,theprincipalaccountingofficerforOpexa).Opexashallmaketheworkpapersandback-upmaterialsusedorusefulinpreparingtheNetCashSchedule,asreasonablyrequestedbyAcer,availabletoAcerand,ifrequestedbyAcer,itsaccountantsandcounselatreasonabletimesanduponreasonablenotice.EitherPartymayrequestaredeterminationofNetCashifitisdeterminedthattheactualClosingDateistooccuraftertheAnticipatedClosingDateandsuchPartyreasonablybelievesamaterialchangetothecalculationofNetCashwillthusoccur(providedthateitherPartymayrequestaredeterminationofNetCashiftheactualClosingDateistooccurmorethanfive(5)BusinessDaysaftertheAnticipatedClosingDate).

(b) Withinfive(5)calendardaysafterOpexadeliverstheNetCashSchedule(the“ResponseDate”),AcerwillhavetherighttodisputeanypartofsuchNetCashSchedulebydeliveringawrittennoticetothateffecttoOpexa(a“DisputeNotice”).AnyDisputeNoticeshallidentifyinreasonabledetailthenatureofanyproposedrevisionstotheNetCashCalculation.

(c) IfonorpriortotheResponseDate,(i)AcernotifiesOpexainwritingthatithasnoobjectionstotheNetCashCalculationor(ii)AcerfailstodeliveraDisputeNoticeasprovidedinSection1.6(b),thentheNetCashCalculationassetforthintheNetCashScheduleshallbedeemedtohavebeenfinallydeterminedforpurposesofthisAgreementandtorepresenttheNetCashattheAnticipatedClosingDateforpurposesofthisAgreement.

(d) IfAcerdeliversaDisputeNoticeonorpriortotheResponseDate,thenRepresentativesofOpexaandAcershallpromptlymeetandattemptingoodfaithtoresolvethedisputeditem(s)andnegotiateanagreed-upondeterminationofNetCash,whichagreeduponNetCashamountshallbedeemedtohavebeenfinallydeterminedforpurposesofthisAgreementandtorepresenttheNetCashattheAnticipatedClosingDateforpurposesofthisAgreement.

(e) IfRepresentativesofOpexaandAcerareunabletonegotiateanagreed-upondeterminationofNetCashattheAnticipatedClosingDatepursuanttoSection1.6(d)withinthree(3)calendardaysafterdeliveryoftheDisputeNotice(orsuchotherperiodasOpexa

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andAcermaymutuallyagreeupon),thenOpexaandAcershalljointlyselectanindependentauditorofrecognizednationalstanding(the“AccountingFirm”)toresolveanyremainingdisagreementsastotheNetCashCalculation.OpexashallpromptlydelivertotheAccountingFirmtheworkpapersandback-upmaterialsusedinpreparingtheNetCashSchedule,andOpexaandAcershallusecommerciallyreasonableeffortstocausetheAccountingFirmtomakeitsdeterminationwithinten(10)calendardaysofacceptingitsselection.AcerandOpexashallbeaffordedtheopportunitytopresenttotheAccountingFirmanymaterialrelatedtotheunresolveddisputesandtodiscusstheissueswiththeAccountingFirm;provided, however ,thatnosuchpresentationordiscussionshalloccurwithoutthepresenceofaRepresentativeofeachofAcerandOpexa.ThedeterminationoftheAccountingFirmshallbelimitedtothedisagreementssubmittedtotheAccountingFirm.ThedeterminationoftheamountofNetCashmadebytheAccountingFirmshallbedeemedtohavebeenfinallydeterminedforpurposesofthisAgreementandtorepresenttheNetCashattheAnticipatedClosingDateforpurposesofthisAgreement,andthePartiesshalldelaytheClosinguntiltheresolutionofthemattersdescribedinthisSection1.6(e).ThefeesandexpensesoftheAccountingFirmshallbeallocatedbetweenOpexaandAcerinthesameproportionthatthedisputedamountoftheNetCashthatwasunsuccessfullydisputedbysuchParty(asfinallydeterminedbytheAccountingFirm)bearstothetotaldisputedamountoftheNetCashamount(andfortheavoidanceofdoubtthefeesandexpensestobepaidbyOpexashallreducetheNetCash).IfthisSection1.6(e)appliesastothedeterminationoftheNetCashattheAnticipatedClosingDatedescribedinSection1.6(a),uponresolutionofthematterinaccordancewiththisSection1.6(e),thePartiesshallnotberequiredtodetermineNetCashagaineventhoughtheClosingDatemayoccurlaterthantheAnticipatedClosingDate,exceptthateitherPartymayrequestaredeterminationofNetCashifsuchPartyreasonablybelievesamaterialchangetothecalculationofNetCashhasoccurred,oriftheClosingDateismorethanfive(5)BusinessDaysaftertheAnticipatedClosingDate.

(f) OnceNetCashisfinallydeterminedpursuanttothisSection1.6,assumingsuchdeterminationhasbeenmadeinadvanceoftheOpexaStockholders’MeetingitwillbepubliclydisclosedbyOpexainadvancethereof.

1.7 Closing of Acer’s Transfer Books .AttheEffectiveTime:(a)allsharesofAcerCommonStockoutstandingimmediatelypriortotheEffectiveTime(aftergivingeffecttothePreferredStockConversion)shallbetreatedinaccordancewithSection1.5(a),andallholdersofcertificatesrepresentingsharesofAcerCapitalStockthatwereoutstandingimmediatelypriortotheEffectiveTimeshallceasetohaveanyrightsasAcerStockholders;and(b)thestocktransferbooksofAcershallbeclosedwithrespecttoallsharesofAcerCapitalStockoutstandingimmediatelypriortotheEffectiveTime.NofurthertransferofanysuchsharesofAcerCapitalStockshallbemadeonsuchstocktransferbooksaftertheEffectiveTime.If,aftertheEffectiveTime,avalidcertificatepreviouslyrepresentinganysharesofAcerCapitalStock,includinganyvalidcertificaterepresentinganysharesofAcerPreferredStockpreviouslyconvertedintosharesofAcerCommonStockinconnectionwiththePreferredStockConversion,outstandingimmediatelypriortotheEffectiveTime(an“AcerStockCertificate”)ispresentedtotheExchangeAgentortotheSurvivingCorporation,suchAcerStockCertificateshallbecanceledandshallbeexchangedasprovidedinSection1.5andSection1.8.

1.8 Surrender of Certificates.

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(a) OnorpriortotheClosingDate,OpexaandAcershallagreeuponandselectareputablebank,transferagentortrustcompanytoactasexchangeagentintheMerger(the“ExchangeAgent”).AttheEffectiveTime,OpexashalldepositwiththeExchangeAgent:(i)theaggregatenumberofbookentrysharestobeissuedtoAcerStockholdersastheMergerConsiderationpursuanttoSection1.5(a)and(ii)cashsufficienttomakepaymentsinlieuoffractionalsharesinaccordancewithSection1.5(c).ThebookentrysharesofOpexaCommonStockandcashamountssodepositedwiththeExchangeAgent,togetherwithanydividendsordistributionsreceivedbytheExchangeAgentwithrespecttosuchshares,arereferredtocollectivelyasthe“ExchangeFund.”

(b) PromptlyaftertheEffectiveTime,thePartiesshallcausetheExchangeAgenttomailtothePersonswhowererecordholdersofAcerStockCertificatesimmediatelypriortotheEffectiveTime,assetforthontheAllocationCertificate:(i)aletteroftransmittalincustomaryform;and(ii)instructionsforeffectingthesurrenderofAcerStockCertificatesinexchangeforbookentrysharesofOpexaCommonStock.UponsurrenderofanAcerStockCertificatetotheExchangeAgentforexchange,togetherwithadulyexecutedletteroftransmittalandsuchotherdocumentsasmaybereasonablyrequiredbytheExchangeAgent:(A)theholderofsuchAcerStockCertificateshallbeentitledtoreceiveinexchangethereforoneormorebookentrysharesrepresentingtheportionoftheMergerConsideration(inanumberofwholesharesofOpexaCommonStock)thatsuchholderhastherighttoreceivepursuanttotheprovisionsofSection1.5(a)(andcashinlieuofanyfractionalshareofOpexaCommonStockpursuanttotheprovisionsofSection1.5(c));and(B)upondeliveryofsuchconsiderationtotheapplicableholderinaccordancewithSection1.5,theAcerStockCertificatesosurrenderedshallbecanceled.UntilsurrenderedascontemplatedbythisSection1.8(b),eachAcerStockCertificateshallbedeemed,fromandaftertheEffectiveTime,torepresentonlytherighttoreceivesharesofOpexaCommonStock(andcashinlieuofanyfractionalshareofOpexaCommonStock).IfanyAcerStockCertificatehasbeenlost,stolenordestroyed,Opexamay,initsreasonablediscretionandasaconditionprecedenttothedeliveryofanysharesofOpexaCommonStock,requiretheownerofsuchlost,stolenordestroyedAcerStockCertificatetoprovideanapplicableaffidavitwithrespecttosuchAcerStockCertificateandpostabondindemnifyingOpexaagainstanyclaimsufferedbyOpexarelatedtothelost,stolenordestroyedAcerStockCertificateoranyOpexaCommonStockissuedinexchangethereforasOpexamayreasonablyrequest.

(c) NodividendsorotherdistributionsdeclaredormadewithrespecttoOpexaCommonStockwitharecorddateaftertheEffectiveTimeshallbepaidtotheholderofanyunsurrenderedAcerStockCertificatewithrespecttothesharesofOpexaCommonStockthatsuchholderhastherighttoreceiveintheMergeruntilsuchholdersurrenderssuchAcerStockCertificateoranaffidavitoflossordestructioninlieuthereofinaccordancewiththisSection1.8(atwhichtimesuchholdershallbeentitled,subjecttotheeffectofapplicableabandonedproperty,escheatorsimilarlaws,toreceiveallsuchdividendsanddistributions,withoutinterest).

(d) AnyportionoftheExchangeFundthatremainsundistributedtoholdersofAcerStockCertificatessix(6)monthsaftertheClosingDateshallbedeliveredtoOpexaupondemand,andanyholdersofAcerStockCertificateswhohavenottheretoforesurrenderedtheirAcerStockCertificatesinaccordancewiththisSection1.8shallthereafterlookonlytoOpexa

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forsatisfactionoftheirclaimsforOpexaCommonStock,cashinlieuoffractionalsharesofOpexaCommonStockandanydividendsordistributionswithrespecttosharesofOpexaCommonStock.

(e) EachoftheExchangeAgent,OpexaandtheSurvivingCorporationshallbeentitledtodeductandwithholdfromanyconsiderationdeliverablepursuanttothisAgreementtoanyholderofanyAcerStockCertificatesuchamountsasarerequiredtobedeductedorwithheldfromsuchconsiderationundertheCodeorunderanyotherapplicableLegalRequirementandshallbeentitledtorequestanyreasonablyappropriateTaxforms,includinganIRSFormW-9(ortheappropriateIRSFormW-8,asapplicable),fromanyrecipientofpaymentshereunder.Totheextentsuchamountsaresodeductedorwithheld,andremittedtotheappropriateTaxauthority,suchamountsshallbetreatedforallpurposesunderthisAgreementashavingbeenpaidtothePersontowhomsuchamountswouldotherwisehavebeenpaid.

(f) NopartytothisAgreementshallbeliabletoanyholderofanyAcerStockCertificateortoanyotherPersonwithrespecttoanysharesofOpexaCommonStock(ordividendsordistributionswithrespectthereto)orforanycashamountsdeliveredtoanypublicofficialpursuanttoanyapplicableabandonedpropertylaw,escheatlaworsimilarLegalRequirement.

1.9 Appraisal Rights.

(a) NotwithstandinganyprovisionofthisAgreementtothecontrary,sharesofAcerCapitalStockthatareoutstandingimmediatelypriortotheEffectiveTime(otherthansharescanceledpursuanttoSection1.5(a)(i))andareheldbyanAcerStockholderwhohasnotvotedinfavorofadoptionofthisAgreementorconsentedtheretoinwritingandwhohasproperlyexercisedandperfectedappraisalrightsforsuchsharesofAcerCommonStockinaccordancewiththeDGCL(collectively,the“DissentingShares”)shallnotbeconvertedintoorrepresenttherighttoreceivetheportionoftheMergerConsiderationattributabletosuchDissentingShares,butinsteadshallbeentitledtoonlysuchrightsasaregrantedbySection262oftheDGCL;provided, however ,thatifaftertheEffectiveTime,suchstockholderfailstoperfectoreffectivelywithdrawsorotherwiselosessuchholder’sappraisalrightsundertheDGCLorifacourtofcompetentjurisdictiondeterminesthatsuchholderisnotentitledtothereliefprovidedbySection262oftheDGCL,suchsharesofAcerCommonStockshallbedeemedtobeconvertedintoandtohavebecomeexchangeablefor,asoftheEffectiveTime,therighttoreceivetheportionoftheMergerConsiderationattributabletosuchDissentingSharesupontheirsurrenderinthemannerprovidedinSection1.5,withoutinterestthereon.

(b) AcershallgiveOpexapromptwrittennoticeofanydemandsbydissentingstockholdersreceivedbyAcer,withdrawalsofsuchdemandsandanyotherinstrumentsservedonAcerandanymaterialcorrespondencereceivedbyAcerinconnectionwithsuchdemands.

1.10 Further Action .If,atanytimeaftertheEffectiveTime,anyfurtheractionisdeterminedbytheSurvivingCorporationtobenecessaryordesirabletocarryoutthepurposesofthisAgreementortovesttheSurvivingCorporationwithfullright,titleandpossessionofandtoallrightsandpropertyofAcer,thentheofficersanddirectorsoftheSurvivingCorporation

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shallbefullyauthorized,andshallusetheircommerciallyreasonableefforts(inthenameofAcer,inthenameofMergerSubandotherwise)totakesuchaction.

1.11 Tax Consequences .ForfederalincomeTaxpurposes,theMergerisintendedtoconstituteareorganizationwithinthemeaningofSection368(a)oftheCodeandtheTreasuryRegulationspromulgatedthereunder.ThepartiestothisAgreementadoptthisAgreementasa“planofreorganization”withinthemeaningofTreasuryRegulationsSection1.368-2(g).

1.12 Certificates.

(a) OpexawillprepareanddelivertoAceratleasttwo(2)BusinessDayspriortotheClosingDate,acertificatesignedbytheActingChiefFinancialOfficerofOpexa(orifthereisnoActingChiefFinancialOfficer,theprincipalaccountingofficerforOpexa)inaformreasonablyacceptabletoAcer,whichsetsforthatrueandcompletelist,asofimmediatelypriortotheEffectiveTime,ofthenumberofOpexaOutstandingSharesandeachcomponentthereof(brokendownbyoutstandingsharesofOpexaCommonStock,OpexaOptions,OpexaRSUs,OpexaWarrants,andotherrelevantsecurities)(“OpexaOutstandingSharesCertificate”).

(b) AcerwillprepareanddelivertoOpexaatleastone(1)BusinessDaypriortotheClosingDateacertificatesignedbytheChiefFinancialOfficerofAcerinaformreasonablyacceptabletoOpexa,whichsetsforthatrueandcompletelist,asofimmediatelypriortotheEffectiveTime(givingeffecttothePreferredStockConversionandtheclosingoftheAcerPre-ClosingFinancing)of:(a)therecordholdersofAcerCommonStockandAcerOptions;(b)thenumberofsharesofAcerCommonStockownedand/orunderlyingtheAcerOptionsheldbysuchholdersandthepershareexercisepriceforeachsuchAcerOption;and(c)theportionoftheMergerConsiderationeachsuchholderisentitledtoreceivepursuanttoSection1.5(the“AllocationCertificate”).

ARTICLE 2

REPRESENTATIONS AND WARRANTIES OF ACER

AcerrepresentsandwarrantstoOpexaandMergerSubasfollows,exceptassetforthinthewrittendisclosurescheduledeliveredbyAcertoOpexa(the“AcerDisclosureSchedule”)(itbeingunderstoodthattherepresentationsandwarrantiesinthisArticle2arequalifiedby:(a)anyexceptionsanddisclosuressetforthinthesectionorsubsectionoftheAcerDisclosureSchedulecorrespondingtotheparticularsectionorsubsectioninthisArticle2inwhichsuchrepresentationandwarrantyappears;(b)anyexceptionsordisclosuresexplicitlycross-referencedinsuchsectionorsubsectionoftheAcerDisclosureSchedulebyreferencetoanothersectionorsubsectionoftheAcerDisclosureSchedule;and(c)anyexceptionsordisclosuressetforthinanyothersectionorsubsectionoftheAcerDisclosureScheduletotheextentitisreasonablyapparentfromthefaceofsuchexceptionordisclosurethatsuchexceptionordisclosurequalifiessuchrepresentationandwarranty).TheinclusionofanyinformationintheAcerDisclosureScheduleshallnotbedeemedtobeanadmissionoracknowledgement,inandofitself,thatsuchinformationisrequiredbythetermshereoftobedisclosed,ismaterial,has

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resultedinorwouldresultinanAcerMaterialAdverseEffect,orisoutsidetheOrdinaryCourseofBusiness.

2.1 Subsidiaries; Due Organization; Organizational Documents.

(a) AcerdoesnothaveanySubsidiariesanddoesnotownanycapitalstockof,oranyequityinterestofanynaturein,anyEntity.Acerhasneitheragreednorisobligatedtomake,norisboundbyanyContractunderwhichitmaybecomeobligatedtomake,anyfutureinvestmentinorcapitalcontributiontoanyotherEntity.Acerhasnot,atanytime,beenageneralpartnerof,orotherwisebeenliableforanyofthedebtsorotherobligationsof,anygeneralpartnership,limitedpartnershiporotherEntity.

(b) Acerisacorporationdulyorganized,validlyexistingandingoodstandingunderthelawsofthejurisdictionofitsincorporation,andhasallnecessarypowerandauthority:(i)toconductitsbusinessinthemannerinwhichitsbusinessiscurrentlybeingconducted;(ii)toownanduseitsassetsinthemannerinwhichitsassetsarecurrentlyownedandused;and(iii)toperformitsobligationsunderallAcerContracts.

(c) Acerisqualifiedtodobusinessasaforeigncorporation,andisingoodstanding,underthelawsofalljurisdictionswherethenatureofitsbusinessrequiressuchqualificationotherthaninjurisdictionswherethefailuretobesoqualifiedwouldnotconstituteanAcerMaterialAdverseEffect.

(d) EachdirectorandofficerofAcerasofthedateofthisAgreementissetforthinSection2.1(d)oftheAcerDisclosureSchedule.

(e) AcerhasdeliveredormadeavailabletoOpexaaccurateandcompletecopiesofitscertificateofincorporation,bylawsandothercharterandorganizationaldocuments,includingallcurrentlyeffectiveamendmentsthereto.Acerisnotinmaterialviolationofanyoftheprovisionsofitsorganizationaldocuments.

2.2 Authority; Vote Required.

(a) AcerhasallnecessarycorporatepowerandauthoritytoenterintoandtoperformitsobligationsunderthisAgreement.TheAcerBoardofDirectorshas:(i)determinedthattheMergerisfairto,andinthebestinterestsofAcerandAcerStockholders;(ii)dulyauthorizedandapprovedbyallnecessarycorporateaction,theexecution,deliveryandperformanceofthisAgreementandtheContemplatedTransactions;(iii)recommendedtheapprovaloftheAcerStockholderMattersbytheAcerStockholdersanddirectedthattheAcerStockholderMattersbesubmittedforconsiderationbyAcerStockholdersinconnectionwiththesolicitationoftheRequiredAcerStockholderVote;and(iv)approvedtheAcerStockholderSupportAgreementsandthetransactionscontemplatedthereby.ThisAgreementhasbeendulyexecutedanddeliveredbyAcerand,assumingthedueauthorization,executionanddeliverybyOpexaandMergerSub,constitutesthelegal,validandbindingobligationofAcer,enforceableagainstAcerinaccordancewithitsterms,subjectto:(A)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtors;and(B)rulesoflawgoverningspecificperformance,injunctivereliefandotherequitableremedies.

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(b) Theaffirmativevoteoftheholdersof(i)amajorityofthesharesofAcerPreferredStockandCommonStock,votingtogetherasasingleclass;and(ii)greaterthan50%ofthesharesofAcerPreferredStock,votingtogetherasasingleclassand(iii)greaterthan50%ofthesharesofAcerSeriesBPreferredStock,votingtogetherasasingleclass,ineachcase,asoutstandingontherecorddateforthewrittenconsentinlieuofameetingpursuanttoSection228oftheDGCLapprovingtheAcerStockholderMatters,inaformreasonablyacceptabletoOpexa(each,an“AcerStockholderWrittenConsent”andcollectively,the“AcerStockholderWrittenConsents”)andentitledtovotethereon(collectively,the“RequiredAcerStockholderVote”),istheonlyvoteoftheholdersofanyclassorseriesofAcerCapitalStocknecessarytoapprovetheAcerStockholderMatters.ThesharesofAcerCapitalStockcoveredbytheAcerStockholderSupportAgreementsaresufficienttoobtaintheRequiredAcerStockholderVote.

2.3 Non-Contravention; Consents.

(a) TheexecutionanddeliveryofthisAgreementbyAcerdoesnot,andtheperformanceofthisAgreementbyAcerwillnot,(i)conflictwithorviolatethecertificateofincorporationorbylawsofAcer;(ii)subjecttoobtainingtheRequiredAcerStockholderVoteandcompliancewiththerequirementssetforthinSection2.3(b)below,conflictwithorviolateanyLegalRequirementapplicabletoAcerorbywhichitspropertiesareboundoraffected,exceptforanysuchconflictsorviolationsthatwouldnotconstituteanAcerMaterialAdverseEffect;or(iii)requireAcertomakeanyfilingwithorgiveanynoticeormakeanypaymenttoaPerson,orobtainanyConsentfromaPerson,orresultinanybreachoforconstituteadefault(oraneventthatwithnoticeorlapseoftimeorbothwouldbecomeadefault)under,orimpairAcer’srightsoraltertherightsorobligationsofanythirdpartyunder,orgivetoothersanyrightsoftermination,amendment,accelerationorcancelationof,orresultinthecreationofanEncumbranceonanyofthepropertiesorassetsofAcerpursuantto,anyAcerMaterialContract.

(b) NomaterialConsentororderof,orregistration,declarationorfilingwith,anyGovernmentalBodyisrequiredbyorwithrespecttoAcerinconnectionwiththeexecutionanddeliveryofthisAgreementortheconsummationoftheContemplatedTransactions,exceptfor(i)thefilingoftheCertificateofMergerwiththeSecretaryofStateoftheStateofDelawarepursuanttotheDGCL,(ii)anyrequiredfilingsundertheHSRActandanyforeignantitrustLegalRequirementand(iii)suchConsents,orders,registrations,declarationsandfilingsasmayberequiredunderapplicablefederalandstatesecuritieslaws.

2.4 Capitalization.

(a) TheauthorizedcapitalstockofAcerasofthedateofthisAgreementconsistsof:(i)10,000,000sharesofcommonstock,parvalue$0.0001pershare(the“AcerCommonStock”),ofwhich2,450,000sharesareissuedandoutstandingasofthedateofthisAgreement;and(ii)1,608,654sharesofpreferredstock,parvalue$0.0001pershare(the“AcerPreferredStock”),ofwhich638,416sharesaredesignatedasSeriesAPreferredStock,allofwhichareissuedandoutstandingasofthedateofthisAgreement,andofwhich970,238sharesaredesignatedasSeriesBPreferredStock(the“AcerSeriesBPreferredStock”),allofwhichareissuedandoutstandingasofthedateofthisAgreement.Acerdoesnotholdanyofitscapitalstockintreasury.AlloftheoutstandingsharesofAcerCapitalStockhavebeendulyauthorizedandvalidlyissued,andarefullypaidandnonassessable.Section2.4(a)oftheAcerDisclosure

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Schedulelists,asofthedateofthisAgreement,eachrecordholderofissuedandoutstandingAcerCapitalStockandthenumberandtypeofsharesofAcerCapitalStockheldbysuchholder.EachshareofAcerPreferredStockisconvertibleintoone(1)shareofAcerCommonStock.

(b) ExceptfortheAcer2013StockIncentivePlan(the“2013Plan”),Acerdoesnothaveanystockoptionplanoranyotherplan,program,agreementorarrangementprovidingforanyequity-basedcompensationforanyPerson.Acerhasreserved165,000sharesofAcerCommonStockforissuanceunderthe2013Plan.AsofthedateofthisAgreement,ofsuchreservedsharesofAcerCommonStock,116,375shareshavebeengrantedandarecurrentlyoutstanding,and48,625sharesofAcerCommonStockremainavailableforfutureissuancepursuanttothe2013Plan.Section2.4(b)oftheAcerDisclosureSchedulesetsforththefollowinginformationwithrespecttoeachAcerOptionoutstanding,asofthedateofthisAgreement:(A)thenameoftheoptionee;(B)thenumberofsharesofAcerCommonStocksubjecttosuchAcerOptionasofthedateofthisAgreement;(C)theexercisepriceofsuchAcerOption;(D)thedateonwhichsuchAcerOptionwasgranted;and(E)thedateonwhichsuchAcerOptionexpires.NovestingofAcerOptionswillaccelerateasaresultoftheMerger.

(c) ExceptfortheoutstandingAcerOptionssetforthonSection2.4(b)oftheAcerDisclosureSchedule,thereisno:(i)outstandingsubscription,option,call,warrantorright(whetherornotcurrentlyexercisable)toacquireanysharesofthecapitalstockorothersecuritiesofAcer;(ii)outstandingsecurity,instrumentorobligationthatisormaybecomeconvertibleintoorexchangeableforanysharesofthecapitalstockorothersecuritiesofAcer;(iii)stockholderrightsplan(orsimilarplancommonlyreferredtoasa“poisonpill”)orContractunderwhichAcerisormaybecomeobligatedtosellorotherwiseissueanysharesofitscapitalstockoranyothersecurities;or(iv)conditionorcircumstancethatmaygiverisetoorprovideabasisfortheassertionofaclaimbyanyPersontotheeffectthatsuchPersonisentitledtoacquireorreceiveanysharesofcapitalstockorothersecuritiesofAcer.Therearenooutstandingorauthorizedstockappreciation,phantomstock,profitparticipation,restrictedstockunits,equity-basedorothersimilarrightswithrespecttoAcer.

(d) (i)NoneoftheoutstandingsharesofAcerCapitalStockareentitledorsubjecttoanypreemptiveright,rightofrepurchaseorforfeiture,rightofparticipation,rightofmaintenanceoranysimilarright;(ii)noneoftheoutstandingsharesofAcerCapitalStockaresubjecttoanyrightoffirstrefusalinfavorofAcer;(iii)therearenooutstandingbonds,debentures,notesorotherindebtednessofAcerhavingarighttovoteonanymattersonwhichtheAcerStockholdershavearighttovote;(iv)thereisnoAcerContracttowhichAcerisapartyrelatingtothevotingorregistrationof,orrestrictinganyPersonfrompurchasing,selling,pledgingorotherwisedisposingof(orfromgrantinganyoptionorsimilarrightwithrespectto),anysharesofAcerCapitalStock.Acerisnotunderanyobligation,orboundbyanyContractpursuanttowhichitmaybecomeobligated,torepurchase,redeemorotherwiseacquireanyoutstandingsharesofAcerCapitalStockorothersecurities.

(e) AlloutstandingsharesofAcerCapitalStock,aswellasallAcerOptions,havebeenissuedandgranted,asapplicable,inmaterialcompliancewithallapplicablesecuritieslawsandotherapplicableLegalRequirements.

2.5 Financial Statements.

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(a) Section2.5(a)oftheAcerDisclosureScheduleincludestrueandcompletecopiesof(i)Acer’sauditedconsolidatedbalancesheetsatDecember31,2015andDecember31,2016,(ii)theAcerUnauditedInterimBalanceSheet,(iii)Acer’sauditedconsolidatedstatementsofoperations,cashflowsandchangesinstockholders’equityfortheyearsendedDecember31,2015andDecember31,2016,and(iv)Acer’sunauditedstatementsofoperations,cashflowsandchangesinstockholders’equityforthethree(3)monthsendedMarch31,2017(collectively,the“AcerFinancials”).TheAcerFinancials(A)werepreparedinaccordancewithUnitedStatesgenerallyacceptedaccountingprinciples(“GAAP”)(exceptasmaybeindicatedinthefootnotestosuchAcerFinancialsandthatunauditedfinancialstatementsmaynothavenotestheretoandotherpresentationitemsthatmayberequiredbyGAAPandaresubjecttonormalandrecurringyear-endadjustmentsthatarenotreasonablyexpectedtobematerialinamount)appliedonaconsistentbasisunlessotherwisenotedthereinthroughouttheperiodsindicatedand(B)fairlypresentthefinancialconditionandoperatingresultsofAcerasofthedatesandfortheperiodsindicatedtherein.

(b) Acermaintainsasystemofinternalaccountingcontrolsdesignedtoprovidereasonableassurancethat:(i)transactionsareexecutedinaccordancewithmanagement’sgeneralorspecificauthorizations;(ii)transactionsarerecordedasnecessarytopermitpreparationoffinancialstatementsinconformitywithGAAPandtomaintainassetaccountability;(iii)accesstoassetsispermittedonlyinaccordancewithmanagement’sgeneralorspecificauthorization;and(iv)therecordedaccountabilityforassetsiscomparedwiththeexistingassetsatreasonableintervalsandappropriateactionistakenwithrespecttoanydifferences.AcermaintainsinternalcontroloverfinancialreportingthatprovidesreasonableassuranceregardingthereliabilityoffinancialreportingandthepreparationoffinancialstatementsforexternalpurposesinaccordancewithGAAP.

2.6 Absence of Changes .SinceMarch31,2017throughthedateofthisAgreement,AcerhasconducteditsbusinessintheOrdinaryCourseofBusinessandtherehasnotbeen(a)anyeventthathashadanAcerMaterialAdverseEffectoranyevent,condition,change,oreffectthatcouldreasonablybeexpectedtohave,individuallyorintheaggregate,anAcerMaterialAdverseEffector(b)anyaction,eventoroccurrencethatwouldhaverequiredconsentofOpexapursuanttoSection4.3(b)ofthisAgreementhadsuchaction,eventoroccurrencetakenplaceaftertheexecutionanddeliveryofthisAgreement.

2.7 Title to Assets .Acerowns,andhasgoodandvalidtitleto,or,inthecaseofleasedpropertiesandassets,validleaseholdinterestsin,alltangiblepropertiesorassetsandequipmentusedorheldforuseinitsbusinessoroperationsorpurportedtobeownedbyit,ineachcase,freeandclearofanyEncumbrances,exceptfor:(i)anylienforcurrentTaxesnotyetdueandpayableorforTaxesthatarebeingcontestedingoodfaithandforwhichadequatereserveshavebeenmadeontheAcerUnauditedInterimBalanceSheet;(ii)minorliensthathavearisenintheOrdinaryCourseofBusinessandthatdonot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheassetssubjecttheretoormateriallyimpairtheoperationsofAcer;and(iii)lienslistedinSection2.7oftheAcerDisclosureSchedule.

2.8 Real Property; Leaseholds . Acerneithercurrentlyowns,norhasiteverownedanyrealpropertyoranyinterestinrealproperty,exceptfortheleaseholdscreatedundertherealpropertyleases(includinganyamendmentsthereto)identifiedinSection2.8oftheAcer

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DisclosureSchedule(the“AcerLeases”),whichareeachinfullforceandeffective,withnoexistingmaterialdefaultthereunder.Acer’spossessionandquietenjoymentoftheleasedrealestateundersuchAcerLeaseshasnotbeendisturbed,andtotheKnowledgeofAcer,therearenodisputeswithrespecttosuchAcerLeases.AcerhasnotcreatedanyEncumbrancesontherealestateundertheAcerLeases.

2.9 Intellectual Property.

(a) Acerowns,orhastherighttouse,andhastherighttobringactionsfortheinfringementof,allAcerIPRights,exceptforanyfailuretoownorhavetherighttouse,orhavetherighttobringactionsthatwouldnotconstituteanAcerMaterialAdverseEffect.

(b) Section2.9(b)oftheAcerDisclosureScheduleisanaccurate,trueandcompletelistingofallAcerRegisteredIP.

(c) Section2.9(c)oftheAcerDisclosureScheduleaccuratelyidentifies(i)allAcerIPRightslicensedtoAcer(otherthan(A)anynon-customizedsoftwarethat(1)issolicensedsolelyinexecutableorobjectcodeformpursuanttoanon-exclusive,internalusesoftwarelicenseandotherIntellectualPropertyassociatedwithsuchsoftwareand(2)isnotincorporatedinto,ormaterialtothedevelopment,manufacturing,ordistributionof,anyofAcer’sproductsorservicesand(B)anyIntellectualPropertylicensedancillarytothepurchaseoruseofequipment,reagentsorothermaterials);(ii)thecorrespondingAcerContractspursuanttowhichsuchAcerIPRightsarelicensedtoAcer;(iii)whetherthelicenseorlicensesgrantedtoAcerareexclusiveornon-exclusive;and(iv)whetheranyfunding,facilitiesorpersonnelofanyGovernmentalBodywereused,directlyorindirectly,todeveloporcreate,inwholeorinpart,suchAcerIPRights.

(d) Section2.9(d)oftheAcerDisclosureScheduleaccuratelyidentifieseachAcerContractpursuanttowhichanyPerson(otherthanAcer)hasbeengrantedanylicenseoroptiontoobtainalicenseunder,orotherwisehasreceivedoracquiredanyright(whetherornotcurrentlyexercisable)orinterestin,anyAcerIPRights.Acerisnotboundby,andnoAcerIPRightsaresubjectto,anyContractcontaininganycovenantorotherprovisionthatinanywaylimitsorrestrictstheabilityofAcertouse,exploit,assertorenforceanyAcerIPRightsanywhereintheworld,ineachcaseaswouldmateriallylimitthebusinessofAcerascurrentlyconductedorplannedtobeconducted.

(e) Acersolelyownsallright,title,andinteresttoandinAcerIPRights(otherthanAcerIPRights(i)exclusivelyornon-exclusivelylicensedtoAcer,asidentifiedinSection2.9(c)oftheAcerDisclosureSchedule,(ii)anynon-customizedsoftwarethat(A)issolicensedsolelyinexecutableorobjectcodeformpursuanttoanon-exclusive,internalusesoftwarelicenseandotherIntellectualPropertyassociatedwithsuchsoftwareand(B)isnotincorporatedinto,ormaterialtothedevelopment,manufacturing,ordistributionof,anyofAcer’sproductsorservices,and(iii)anyIntellectualPropertylicensedancillarytothepurchaseoruseofequipment,reagentsorothermaterials)freeandclearofanyEncumbrances.Withoutlimitingthegeneralityoftheforegoing:

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(i) AlldocumentsandinstrumentsnecessarytoregisterorapplyfororrenewregistrationofallAcerRegisteredIPhavebeenvalidlyexecuted,deliveredandfiledinatimelymannerwiththeappropriateGovernmentalBodyexceptforanysuchfailure,individuallyorcollectively,thatwouldnot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheAcerRegisteredIPsubjecttheretoormateriallyimpairtheoperationsofAcer.

(ii) EachPersonwhoisorwasanemployeeorcontractorofAcerandwhoisorwasinvolvedinthecreationordevelopmentofanyAcerIPRightshassignedavalid,enforceableagreementcontaininganassignmentofsuchIntellectualPropertytoAcerandconfidentialityprovisionsprotectingtradesecretsandconfidentialinformationofAcer.TotheKnowledgeofAcer,nocurrentorformerstockholder,officer,director,employeeorcontractorofAcerhasanyclaim,right(whetherornotcurrentlyexercisable),orinteresttoorinanyAcerIPRights.TotheKnowledgeofAcer,noemployeeorcontractorofAceris(a)boundbyorotherwisesubjecttoanyContractrestrictinghimorherfromperforminghisorherdutiesforAceror(b)inbreachofanyContractwithanycurrentorformeremployerorotherPersonconcerningAcerIPRightsorconfidentialityprovisionsprotectingtradesecretsandconfidentialinformationcomprisingAcerIPRights.

(iii) Nofunding,facilitiesorpersonnelofanyGovernmentalBodywereused,directlyorindirectly,todeveloporcreate,inwholeorinpart,anyAcerIPRightsinwhichAcerhasanownershipinterest.

(iv) AcerhastakenreasonablestepstomaintaintheconfidentialityofandotherwiseprotectandenforceitsrightsinallproprietaryinformationthatAcerholds,orpurportstohold,asatradesecret.

(v) Acerhasneitherassignednorotherwisetransferredownershipof,oragreedtoassignorotherwisetransferownershipof,anyAcerIPRightstoanyotherPerson.

(vi) TheAcerIPRightsconstituteallIntellectualPropertynecessaryforAcertoconductitsbusinessascurrentlyconductedorplannedtobeconducted.

(f) Themanufacture,marketing,license,saleorintendeduseofanyproductorservicecurrentlyapprovedorsoldorunderpreclinicalorclinicaldevelopmentbyAcer(i)doesnotviolateorconstituteabreachofanylicenseoragreementbetweenAcerandanythirdparty,and,(ii)totheKnowledgeofAcer,doesnotinfringeormisappropriateanyIntellectualPropertyrightofanyotherparty.AcerhasdisclosedincorrespondencetoOpexathethird-partypatentsandpatentapplicationsfoundduringallfreedomtooperatesearchesthatwereconductedbyAcerrelatedtoanyproductortechnologycurrentlylicensedorsoldorunderdevelopmentbyAcer.TotheKnowledgeofAcer,nothirdpartyisinfringinguponormisappropriating,orviolatinganylicenseoragreementwithAcerrelatingto,anyAcerIPRights.Thereisnocurrentor,totheKnowledgeofAcer,pendingchallenge,claimorLegalProceeding(includingopposition,interferenceorotherproceedinginanypatentorothergovernmentoffice)contestingthevalidity,enforceability,ownershiporrighttouse,sell,licenseordisposeofanyAcerIPRights,norhasAcerreceivedanywrittennoticeassertingthatthemanufacture,marketing,license,saleorintendeduseofanyproductorservicecurrentlyapprovedorsoldorunder

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preclinicalorclinicaldevelopmentbyAcerconflictswithorinfringesormisappropriatesorwillconflictwithorinfringeormisappropriatetherightsofanyotherPerson.

(g) EachitemofAcerIPRightsthatisAcerRegisteredIPisandatalltimeshasbeenfiledandmaintainedincompliancewithallapplicableLegalRequirementsandallfilings,paymentsandotheractionsrequiredtobemadeortakentomaintainsuchitemofAcerRegisteredIPinfullforceandeffecthavebeenmadebytheapplicabledeadline,exceptforanyfailuretoperformanyoftheforegoing,individuallyorcollectively,thatwouldnot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheAcerRegisteredIPsubjecttheretoormateriallyimpairtheoperationsofAcer.

(h) Notrademark(whetherregisteredorunregistered)ortradenameowned,used,orappliedforbyAcerconflictsorinterfereswithanytrademark(whetherregisteredorunregistered)ortradenameowned,used,orappliedforbyanyotherPerson.Noneofthegoodwillassociatedwithorinherentinanytrademark(whetherregisteredorunregistered)inwhichAcerhasorpurportstohaveanownershipinteresthasbeenimpairedasdeterminedbyAcerinaccordancewithGAAP.

2.10 Material Contracts.

(a) Section2.10(a)oftheAcerDisclosureScheduleliststhefollowingAcerContracts,effectiveasofthedateofthisAgreement(each,an“AcerMaterialContract”andcollectively,the“AcerMaterialContracts”):

(i) eachAcerContractrelatingtoanymaterialbonus,deferredcompensation,severance,incentivecompensation,pension,profit-sharingorretirementplans,oranyotheremployeebenefitplansorarrangements;

(ii) eachAcerContractrequiringpaymentsbyAcerafterthedateofthisAgreementinexcessof$150,000pursuanttoitsexpresstermsrelatingtotheemploymentof,ortheperformanceofemployment-relatedservicesby,anyPerson,includinganyemployee,consultantorindependentcontractor,orentityprovidingemploymentrelated,consultingorindependentcontractorservices,notterminablebyAceronninety(90)calendardays’orlessnoticewithoutliability,excepttotheextentgeneralprinciplesofwrongfulterminationlawmaylimitAcer’sorsuchsuccessor’sabilitytoterminateemployeesatwill;

(iii) eachAcerContractrelatingtoanyagreementorplan,includinganystockoptionplan,stockappreciationrightplanorstockpurchaseplan,anyofthebenefitsofwhichwillbeincreased,orthevestingofbenefitsofwhichwillbeaccelerated,bytheoccurrenceofanyoftheContemplatedTransactions(eitheraloneorinconjunctionwithanyotherevent,suchasterminationofemployment),orthevalueofanyofthebenefitsofwhichwillbecalculatedonthebasisofanyoftheContemplatedTransactions;

(iv) eachAcerContractrelatingtoanyagreementofindemnificationorguarantynotenteredintointheOrdinaryCourseofBusiness;

(v) eachAcerContractcontaining(A)anycovenantlimitingthefreedomofAcerortheSurvivingCorporationtoengageinanylineofbusinessorcompetewith

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anyPerson,(B)anymost-favoredpricingarrangement,(C)anyexclusivityprovision,or(D)anynon-solicitationprovision;

(vi) eachAcerContractrelatingtocapitalexpendituresandrequiringpaymentsafterthedateofthisAgreementinexcessof$250,000pursuanttoitsexpressterms;

(vii) eachAcerContractrelatingtothedispositionoracquisitionofmaterialassetsoranyownershipinterestinanyEntity;

(viii) eachAcerContractrelatingtoanymortgages,indentures,loans,notesorcreditagreements,securityagreementsorotheragreementsorinstrumentsrelatingtotheborrowingofmoneyorextensionofcreditinexcessof$250,000orcreatinganymaterialEncumbranceswithrespecttoanyassetsofAceroranyloansordebtobligationswithofficersordirectorsofAcer;

(ix) eachAcerContractrequiringpaymentbyortoAcerafterthedateofthisAgreementinexcessof$250,000pursuanttoitsexpresstermsrelatingto:(A)anydistributionagreement(identifyinganythatcontainexclusivityprovisions);(B)anyagreementinvolvingprovisionofservicesorproductswithrespecttoanypre-clinicalorclinicaldevelopmentactivitiesofAcer;(C)anydealer,distributor,jointmarketing,alliance,jointventure,cooperation,developmentorotheragreementcurrentlyinforceunderwhichAcerhascontinuingobligationstodevelopormarketanyproduct,technologyorservice,oranyagreementpursuanttowhichAcerhascontinuingobligationstodevelopanyIntellectualPropertythatwillnotbeowned,inwholeorinpart,byAcer;or(D)anyContracttolicenseanythirdpartytomanufactureorproduceanyproduct,serviceortechnologyofAceroranyContracttosell,distributeorcommercializeanyproductsorserviceofAcer,ineachcase,exceptforAcerContractsenteredintointheOrdinaryCourseofBusiness;

(x) eachAcerContractwithanyPerson,includinganyfinancialadvisor,broker,finder,investmentbankerorotherPerson,providingadvisoryservicestoAcerinconnectionwiththeContemplatedTransactions;

(xi) eachAcerIPRightsAgreementotherthanthosethatareimmaterial;

(xii) eachAcerLease;or

(xiii) anyotherAcerContractthatisnotterminableatwill(withnopenaltyorpayment)byAcerand(A)whichinvolvespaymentorreceiptbyAcerafterthedateofthisAgreementunderanysuchagreement,contractorcommitmentofmorethan$250,000intheaggregate,orobligationsafterthedateofthisAgreementinexcessof$250,000intheaggregate,or(B)thatismaterialtothebusinessoroperationsofAcer.

(b) AcerhasdeliveredormadeavailabletoOpexaaccurateandcomplete(exceptforapplicableredactionsthereto)copiesofallAcerMaterialContracts,includingallamendmentsthereto.TherearenoAcerMaterialContractsthatarenotinwrittenform.Acerhasnot,nortoAcer’sKnowledge,asofthedateofthisAgreementhasanyotherpartytoanAcerMaterialContract,breached,violatedordefaultedunder,orreceivednoticethatithasbreached,

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violatedordefaultedunder,anyofthetermsorconditionsofanyAcerMaterialContractinsuchmanneraswouldpermitanyotherpartytocancelorterminateanysuchAcerMaterialContract,orwouldpermitanyotherpartytoseekdamagesthatwouldresultinanAcerMaterialAdverseEffect.AstoAcer,asofthedateofthisAgreement,eachAcerMaterialContractisvalid,binding,enforceableandinfullforceandeffect,subjectto:(i)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtors;and(ii)rulesoflawgoverningspecificperformance,injunctivereliefandotherequitableremedies.

2.11 Undisclosed Liabilities . AsofthedateofthisAgreement,Acerdoesnothaveanyliability,indebtedness,obligation,expense,claim,deficiency,guarantyorendorsementofanykind,whetheraccrued,absolute,contingent,matured,orunmatured(whetherornotrequiredtobereflectedinthefinancialstatementsinaccordancewithGAAP)(eacha“Liability”),exceptfor:(a)Liabilitiesidentifiedassuchinthe“liabilities”columnoftheAcerUnauditedInterimBalanceSheet;(b)normalandrecurringcurrentLiabilitiesthathavebeenincurredbyAcersincethedateoftheAcerUnauditedInterimBalanceSheetintheOrdinaryCourseofBusinessandthatarenotinexcessof$250,000intheaggregate;(c)LiabilitiesforperformanceintheOrdinaryCourseofBusinessofobligationsofAcerunderAcerContracts,includingthereasonablyexpectedperformanceofsuchAcerContractsinaccordancewiththeirterms(whichwouldnotinclude,forexample,anyinstancesofbreachorindemnification);(d)LiabilitiesincurredinconnectionwiththeContemplatedTransactions;and(f)LiabilitieslistedinSection2.11oftheAcerDisclosureSchedule.

2.12 Compliance; Permits; Restrictions.

(a) Aceris,andsinceJanuary1,2011hasbeen,inmaterialcompliancewithallapplicableLegalRequirements.Noinvestigation,claim,suit,proceeding,auditorotheractionbyanyGovernmentalBodyorauthorityispendingor,totheKnowledgeofAcer,threatenedagainstAcer.ThereisnoContract,judgment,injunction,orderordecreebindinguponAcerwhich(i)hasorwouldreasonablybeexpectedtohavetheeffectofprohibitingormateriallyimpairinganybusinesspracticeofAcer,anyacquisitionofmaterialpropertybyAcerortheconductofbusinessbyAcerascurrentlyconducted,(ii)wouldreasonablybeexpectedtohaveanadverseeffectonAcer’sabilitytocomplywithorperformanycovenantorobligationunderthisAgreement,or(iii)wouldreasonablybeexpectedtohavetheeffectofpreventing,delaying,makingillegalorotherwiseinterferingwiththeMergeroranyoftheContemplatedTransactions.

(b) AcerholdsallrequiredGovernmentalAuthorizationswhicharematerialtotheoperationofthebusinessofAcer(the“AcerPermits”)ascurrentlyconducted.Section2.12(b)oftheAcerDisclosureScheduleidentifieseachAcerPermit.AsofthedateofthisAgreement,AcerisinmaterialcompliancewiththetermsoftheAcerPermits.Noaction,proceeding,revocationproceeding,amendmentprocedure,writ,injunctionorclaimispendingor,totheKnowledgeofAcer,threatened,whichseekstorevoke,limit,suspend,ormateriallymodifyanyAcerPermit.TherightsandbenefitsofeachmaterialAcerPermitwillbeavailabletotheSurvivingCorporationimmediatelyaftertheEffectiveTimeontermssubstantiallyidenticaltothoseenjoyedbyAcerimmediatelypriortotheEffectiveTime.

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(c) Therearenoproceedingspendingor,totheKnowledgeofAcer,threatenedwithrespecttoanallegedviolationbyAceroftheFederalFood,Drug,andCosmeticAct(“FDCA”),FoodandDrugAdministration(“FDA”)regulationsadoptedthereunder,theControlledSubstancesActoranyothersimilarLegalRequirementspromulgatedbytheFDAorothercomparableGovernmentalBodyresponsibleforregulationofthedevelopment,clinicaltesting,manufacturing,sale,marketing,distributionandimportationorexportationofdrugproducts(“DrugRegulatoryAgency”).

(d) AcerholdsallrequiredGovernmentalAuthorizationsissuablebyanyDrugRegulatoryAgencynecessaryfortheconductofthebusinessofAcerascurrentlyconducted,anddevelopment,clinicaltesting,manufacturing,marketing,distributionandimportationorexportation,ascurrentlyconducted,ofanyofitsproductsorproductcandidates(the“AcerProductCandidates”)(collectively,the“AcerRegulatoryPermits”),andnosuchAcerRegulatoryPermithasbeen(i)revoked,withdrawn,suspended,canceledorterminatedor(ii)modifiedinanyadversemanner,otherthanimmaterialadversemodifications.AcerisincomplianceinallmaterialrespectswiththeAcerRegulatoryPermitsandhasnotreceivedanywrittennoticeorotherwrittencommunicationfromanyDrugRegulatoryAgencyregarding(A)anymaterialviolationoforfailuretocomplymateriallywithanytermorrequirementofanyAcerRegulatoryPermitor(B)anyrevocation,withdrawal,suspension,cancelation,terminationormaterialmodificationofanyAcerRegulatoryPermit.AcerhasmadeavailabletoOpexaallinformationrequestedbyOpexainAcer’spossessionorcontrolrelatingtotheAcerProductCandidatesandthedevelopment,clinicaltesting,manufacturing,importationandexportationoftheAcerProductCandidates,includingcompletecopiesofthefollowing(totheextentthereareany):adverseeventreports;clinicalstudyreportsandmaterialstudydata;inspectionreports,noticesofadversefindings,warningletters,filingsandlettersandotherwrittencorrespondencetoandfromanyDrugRegulatoryAgency;andmeetingminuteswithanyDrugRegulatoryAgency.

(e) Allclinical,pre-clinicalandotherstudiesandtestsconductedbyoronbehalfof,orsponsoredby,AcerorinwhichAceroritscurrentproductsorproductcandidates,includingtheAcerProductCandidates,haveparticipatedwere,andifstillpendingarebeing,conductedinallmaterialrespectsinaccordancewithstandardmedicalandscientificresearchproceduresandincompliancewiththeapplicableregulationsoftheDrugRegulatoryAgenciesandotherapplicableLegalRequirements,including21C.F.R.Parts50,54,56,58and312.SinceJanuary1,2011,Acerhasnotreceivedanynotices,correspondenceorothercommunicationsfromanyDrugRegulatoryAgencyrequiring,ortotheKnowledgeofAcerthreateningtoinitiate,theterminationorsuspensionofanyclinicalstudiesconductedbyoronbehalfof,orsponsoredby,AcerorinwhichAceroritscurrentproductsorproductcandidates,includingtheAcerProductCandidates,haveparticipated.

(f) Acerisnotthesubjectofanypending,ortotheKnowledgeofAcer,threatenedinvestigationinrespectofitsbusinessorproductsbytheFDApursuanttoits“Fraud,UntrueStatementsofMaterialFacts,Bribery,andIllegalGratuities”FinalPolicysetforthin56Fed.Reg.46191(September10,1991)andanyamendmentsthereto.TotheKnowledgeofAcer,Acerhasnotcommittedanyacts,madeanystatement,orfailedtomakeanystatement,ineachcaseinrespectofitsbusinessorAcerProductCandidatesthatwouldviolatetheFDA’s“Fraud,UntrueStatementsofMaterialFacts,Bribery,andIllegalGratuities”FinalPolicy,andany

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amendmentsthereto.NoneofAcer,ortotheKnowledgeofAcer,anyofitsofficers,employeesoragentshasbeenconvictedofanycrimeorengagedinanyconductthatwouldreasonablybeexpectedtoresultinadebarmentorexclusion(i)under21U.S.C.Section335aor(ii)anysimilarapplicableLegalRequirement.TotheKnowledgeofAcer,nodebarmentorexclusionaryclaims,actions,proceedingsorinvestigationsinrespectoftheirbusinessorproductsarependingorthreatenedagainstAceroranyofitsofficers,employeesoragents.

2.13 Tax Matters.

(a) AcerhastimelyfiledallfederalincomeTaxReturnsandothermaterialTaxReturnsthattheywererequiredtofileunderapplicableLegalRequirements.AllsuchTaxReturnswerecorrectandcompleteinallmaterialrespectsandhavebeenpreparedinmaterialcompliancewithallapplicableLegalRequirements.AcerisnotcurrentlythebeneficiaryofanyextensionoftimewithinwhichtofileanyTaxReturn.NoclaimhaseverbeenmadebyanauthorityinajurisdictionwhereAcerdoesnotfileTaxReturnsthatitissubjecttotaxationbythatjurisdiction.

(b) AllmaterialTaxesdueandowingbyAceronorbeforethedatehereof(whetherornotshownonanyTaxReturn)havebeenpaid.TheunpaidTaxesofAcerhavebeenreservedforontheAcerUnauditedInterimBalanceSheetinaccordancewithGAAP.SincethedateoftheAcerUnauditedInterimBalanceSheet,AcerhasnotincurredanyLiabilityforTaxesoutsidetheOrdinaryCourseofBusinessorotherwiseinconsistentwithpastcustomandpractice.

(c) AcerhaswithheldandpaidallTaxesrequiredtohavebeenwithheldandpaidinconnectionwithanyamountspaidorowingtoanyemployee,independentcontractor,creditor,stockholderorotherthirdparty.

(d) TherearenoEncumbrancesforTaxes(otherthanTaxesnotyetdueandpayableorTaxesthatarebeingcontestedingoodfaithandforwhichadequatereserveshavebeenmadeonAcer’sUnauditedInterimBalanceSheet)uponanyoftheassetsofAcer.

(e) NomaterialdeficienciesforTaxeswithrespecttoAcerhavebeenclaimed,proposedorassessedbyanyGovernmentalBodyinwriting.Therearenopending(or,basedonwrittennotice,threatened)audits,assessmentsorotheractionsfororrelatingtoanyliabilityinrespectofTaxesofAcer.NoissuesrelatingtoTaxesofAcerwereraisedbytherelevantTaxauthorityinanycompletedauditorexaminationthatwouldreasonablybeexpectedtoresultinamaterialamountofTaxesinalatertaxableperiod.AcerhasdeliveredormadeavailabletoOpexacompleteandaccuratecopiesofallfederalincomeTaxandallothermaterialTaxReturnsofAcer(anditspredecessors)foralltaxableyearsremainingopenundertheapplicablestatuteoflimitations,andcompleteandaccuratecopiesofallexaminationreportsandstatementsofdeficienciesassessedagainstoragreedtobyAcer(anditspredecessors),withrespecttofederalincomeTaxandallothermaterialTaxes.NeitherAcernoranyofitspredecessorshaswaivedanystatuteoflimitationsinrespectofTaxesoragreedtoanyextensionoftimewithrespecttoaTaxassessmentordeficiency,norhasanyrequestbeenmadeinwritingforanysuchextensionorwaiver.

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(f) AllmaterialelectionswithrespecttoTaxesaffectingAcerasofthedatehereofaresetforthonSection2.13(f)oftheAcerDisclosureSchedule.Acerhasnot(i)consentedatanytimeunderformerSection341(f)(1)oftheCodetohavetheprovisionsofformerSection341(f)(2)oftheCodeapplytoanydispositionoftheassetsofAcer;(ii)agreed,orisrequired,tomakeanyadjustmentunderSection481(a)oftheCodebyreasonofachangeinaccountingmethodorotherwise;(iii)madeanelection,orisrequired,totreatanyofitsassetsasownedbyanotherPersonforTaxpurposesorasatax-exemptbondfinancedpropertyortax-exemptusepropertywithinthemeaningofSection168oftheCode;(iv)acquiredorownsanyassetsthatdirectlyorindirectlysecureanydebttheinterestonwhichistaxexemptunderSection103(a)oftheCode;(v)madeorwillmakeaconsentdividendelectionunderSection565oftheCode;(vi)electedatanytimetobetreatedasanScorporationwithinthemeaningofSections1361or1362oftheCode;or(vii)madeanyoftheforegoingelectionsorisrequiredtoapplyanyoftheforegoingrulesunderanycomparableprovisionofstate,localorforeignlaw.

(g) AcerhasnotbeenaUnitedStatesrealpropertyholdingcorporationwithinthemeaningofSection897(c)(2)oftheCodeduringtheapplicableperiodspecifiedinSection897(c)(1)(A)(ii)oftheCode.

(h) AcerisnotapartytoanyTaxallocation,Taxsharingorsimilaragreement(includingindemnityarrangements),otherthancommercialcontractsenteredintointheOrdinaryCourseofBusinesswithvendors,customersandlandlords.

(i) Acerhasneverbeenamemberofanaffiliatedgroupfilingaconsolidated,combinedorunitaryTaxReturn(otherthanagroupthecommonparentofwhichisAcer)forfederal,state,localorforeignTaxpurposes.AcerhasnoLiabilityfortheTaxesofanyPerson(otherthanAcer)underTreasuryRegulationsSection1.1502-6(oranysimilarprovisionofstate,local,orforeignlaw),asatransfereeorsuccessor,byContract,orotherwise.

(j) AcerhasnotdistributedstockofanotherPerson,orhashaditsstockdistributedbyanotherPerson,inatransactionthatwaspurportedorintendedtobegovernedinwholeorinpartbySection355oftheCodeorSection361oftheCode.

(k) Acerwillnotberequiredtoincludeanyitemofincomein,orexcludeanyitemofdeductionfrom,taxableincomeforanyperiod(oranyportionthereof)endingaftertheClosingDateasaresultofany(i)installmentsaleorotheropentransactiondispositionmadeonorpriortotheClosingDate,or(ii)agreementwithanyTaxauthority(includinganyclosingagreementdescribedinSection7121oftheCodeoranysimilarprovisionofstate,localorforeignlaw)madeorenteredintoonorpriortotheClosingDate.

(l) AcerisnotapartnerforTaxpurposeswithrespecttoanyjointventure,partnership,or,totheKnowledgeofAcer,otherarrangementorcontractwhichistreatedasapartnershipforTaxpurposes.

(m) Acerhasnotenteredintoanytransactionidentifiedasa“listedtransaction”forpurposesofTreasuryRegulationsSections1.6011-4(b)(2)or301.6111-2(b)(2).

(n) Acerhasnottakenanyaction,andtotheKnowledgeofAcer,thereisnofactorcircumstancethatwouldreasonablybeexpectedtopreventtheContemplated

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TransactionsfromqualifyingasareorganizationwithinthemeaningofSection368(a)oftheCode.

2.14 Employee and Labor Matters; Benefit Plans.

(a) TheemploymentofeachoftheAceremployeesisterminablebyAceratwill(orotherwiseinaccordancewithgeneralprinciplesofwrongfulterminationlaw).

(b) Acerisnotapartytoorboundby,norhasadutytobargainunder,anycollectivebargainingagreementorotherContractwithalabororganizationrepresentinganyofitsemployees,andtherearenolabororganizationsrepresenting,purportingtorepresentor,totheKnowledgeofAcer,seekingtorepresentanyemployeesofAcer.

(c) Therehasneverbeen,nor,totheKnowledgeofAcerhastherebeenanythreatof,anystrike,slowdown,workstoppage,lockout,jobaction,unionorganizingactivityoranysimilaractivityordispute,affectingAcer.

(d) Acerisnot,andhasneverbeen,engagedinanyunfairlaborpracticewithinthemeaningoftheNationalLaborRelationsAct.ThereisnoLegalProceeding,claim,labordisputeorgrievancependingor,totheKnowledgeofAcer,threatenedorreasonablyanticipatedrelatingtoanyemploymentcontract,privacyright,labordispute,wagesandhours,leaveofabsence,plantclosingnotification,workers’compensationpolicy,long-termdisabilitypolicy,harassment,retaliation,immigration,employmentstatuteorregulation,safetyordiscriminationmatterinvolvinganyAcerAssociate,includingchargesofunfairlaborpracticesordiscriminationcomplaints.

(e) Section2.14(e)oftheAcerDisclosureSchedulelists,asofthedateofthisAgreement,allwrittenanddescribesallnon-writtenemployeebenefitplans(asdefinedinSection3(3)ofERISA)andallbonus,equity-based,retention,incentive,deferredcompensation,retirementorsupplementalretirement,profitsharing,severance,goldenparachute,disability,lifeoraccidentinsurance,paidtimeoff,vacation,cafeteria,dependentcare,medicalcare,employeeassistanceprogram,educationortuitionassistanceprograms,fringeoremployeebenefit,andallothercompensation,plans,programs,agreementsorarrangements,includingbutnotlimitedtoanyemployment,consulting,independentcontractor,severanceorexecutivecompensationagreementsorarrangements(otherthanregularsalaryorwages),writtenorotherwise,whicharecurrentlyineffectrelatingtoanypresentorformeremployee,independentcontractorordirectorofAceroranyAcerAffiliateorwhichismaintainedby,administeredorcontributedtoby,orrequiredtobecontributedtoby,AceroranyAcerAffiliate,orunderwhichAceroranyAcerAffiliatehasanycurrentorwouldreasonablybeexpectedtoincurliabilityafterthedatehereof(each,an“AcerEmployeePlan”).

(f) WithrespecttoAcerOptionsgrantedpursuanttothe2013Plan,totheKnowledgeofAcer,(i)eachAcerOptionintendedtoqualifyasan“incentivestockoption”underSection422oftheCodesoqualifies,(ii)eachgrantofanAcerOptionwasdulyauthorizednolaterthanthedateonwhichthegrantofsuchAcerOptionwasbyitstermstobeeffective(the“GrantDate”)byallnecessarycorporateaction,including,asapplicable,approvalbytheAcerBoardofDirectors(oradulyconstitutedandauthorizedcommitteethereof)andanyrequired

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stockholderapprovalbythenecessarynumberofvotesorwrittenconsents,andtheawardagreementgoverningsuchgrant(ifany)wasdulyexecutedanddeliveredbyeachpartythereto,(iii)eachAcerOptiongrantwasmadeinaccordancewiththetermsofthe2013PlanandallotherapplicableLegalRequirementsand(iv)thepershareexercisepriceofeachAcerOptionwasnotlessthanthefairmarketvalueofashareofAcerCommonStockontheapplicableGrantDate.

(g) EachAcerEmployeePlanthatisintendedtobequalifiedunderSection401(a)oftheCodehasreceivedafavorabledeterminationormayrelyonafavorableopinionletterwithrespecttosuchqualifiedstatusfromtheInternalRevenueService.TotheKnowledgeofAcer,nothinghasoccurredthatwouldreasonablybeexpectedtoadverselyaffectthequalifiedstatusofanysuchAcerEmployeePlanortheexemptstatusofanyrelatedtrust.

(h) EachAcerEmployeePlanhasbeenmaintainedincompliance,inallmaterialrespects,withitstermsand,bothastoformandoperation,withallapplicableLegalRequirements,includingtheCodeandERISA.AcerandeachAcerAffiliatehasperformedallobligationsrequiredtobeperformedbyitunder,isnotindefaultunderorinviolationof,andhasnoknowledgeofanydefaultorviolationbyanyotherpartyto,anyoftheAcerEmployeePlans.NeitherAcernoranyAcerAffiliateissubjecttoanyLiabilityorpenaltyunderSections4976through4980oftheCodeorTitleIofERISAwithrespecttoanyoftheAcerEmployeePlans.AllcontributionsrequiredtobemadebyAceroranyAcerAffiliatetoanyAcerEmployeePlanhavebeenmadeonorbeforetheirduedates(andnofurthercontributionswillbedueorwillhaveaccruedthereunderasoftheClosingDate,otherthancontributionsaccruedintheordinarycourseofbusinessconsistentwithpastpractice).Nosuit,administrativeproceeding,actionorotherlitigationhasbeeninitiatedagainst,ortotheKnowledgeofAcer,isthreatenedagainstorwithrespecttoanyAcerEmployeePlan,includinganyauditorinquirybytheIRS,theUnitedStatesDepartmentofLabororotherGovernmentalBody.

(i) AcerhasnotengagedinanytransactioninviolationofSections404or406ofERISAorany“prohibitedtransaction,”asdefinedinSection4975(c)(1)oftheCode,forwhichnoexemptionexistsunderSection408ofERISAorSection4975(c)(2)or(d)oftheCode,orhasotherwiseviolatedtheprovisionsofPart4ofTitleI,SubtitleBofERISA.AcerhasnotknowinglyparticipatedinaviolationofPart4ofTitleI,SubtitleBofERISAbyanyplanfiduciaryofanyAcerEmployeePlansubjecttoERISAandAcerhasnotbeenassessedanycivilpenaltyunderSection502(l)ofERISA.

(j) NoAcerEmployeePlanissubjecttoTitleIVorSection302ofERISAorSection412oftheCode,andneitherAcernoranyAcerAffiliatehasevermaintained,contributedtoorpartiallyorcompletelywithdrawnfrom,orincurredanyobligationorliabilitywithrespectto,anysuchplan.NoAcerEmployeePlanisaMultiemployerPlan,andneitherAcernoranyAcerAffiliatehasevercontributedtoorhadanobligationtocontribute,orincurredanyliabilityinrespectofacontribution,toanyMultiemployerPlan.

(k) NoAcerEmployeePlanprovidesformedicalordeathbenefitsbeyondterminationofserviceorretirement,otherthan(i)pursuanttoCOBRAorananalogousstatelawrequirementor(ii)deathorretirementbenefitsunderanAcerEmployeePlanqualifiedunderSection401(a)oftheCode.Acerdoesnotsponsorormaintainanyself-fundedemployeebenefit

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plan.NoAcerEmployeePlanissubjecttoanyLegalRequirementofaforeignjurisdictionoutsideoftheUnitedStates.

(l) AcerisnotapartytoanyContractthathasresultedorwouldreasonablybeexpectedtoresult,separatelyorintheaggregate,inthepaymentof(i)any“excessparachutepayment”withinthemeaningofsection280GoftheCodeasaresultoftheContemplatedTransactionsand(ii)anyamountthedeductionforwhichwouldbedisallowedunderSection162(m)oftheCode.

(m) TotheKnowledgeofAcer,nopaymentpursuanttoanyAcerEmployeePlanorotherarrangementtoany“serviceprovider”(assuchtermisdefinedinSection409AoftheCodeandtheUnitedStatesTreasuryRegulationsandIRSguidancethereunder)fromAcer,includingthegrant,vestingorexerciseofanystockoption,wouldsubjectanyPersontotaxpursuanttoSection409A(1)oftheCode,whetherpursuanttotheContemplatedTransactionsorotherwise.

(n) NoAcerOption,stockappreciationrightsorotherequity-basedawardsissueorgrantedbyAceraresubjecttotherequirementsofCodeSection409A.Each“nonqualifieddeferredcompensationplan”(assuchtermisdefinedunderSection409A(d)(1)oftheCodeandguidancethereunder)maintainedbyorunderwhichAcermakes,isobligatedtomakeorpromisestomake,payments(eacha“Acer409APlan”)compliesinallmaterialrespects,inbothformandoperation,withtherequirementsofCodeSection409Aandtheguidancethereunder.NopaymenttobemadeunderanyAcer409APlanis,ortotheKnowledgeofAcerwillbe,subjecttothepenaltiesofCodeSection409A(a)(1).

(o) Acerhascompliedinallmaterialrespectswithallstateandfederallawsapplicabletoemployees,includingbutnotlimitedtoCOBRA,FMLA,CFRA,HIPAA,theWomen’sHealthandCancerRightsActof1998,theNewborn’sandMothers’HealthProtectionActof1996,andanysimilarprovisionsofstatelawapplicabletoitsemployees.TotheextentrequiredunderHIPAAandtheregulationsissuedthereunder,Acerhas,priortotheClosingDate,performedallobligationsunderthemedicalprivacyrulesofHIPAA(45C.F.R.Parts160and164),theelectronicdatainterchangerequirementsofHIPAA(45C.F.R.Parts160and162),andthesecurityrequirementsofHIPAA(45C.F.R.Part142).AcerdoesnothaveanymaterialunsatisfiedobligationstoanyemployeesorqualifiedbeneficiariespursuanttoCOBRA,HIPAAoranystatelawgoverninghealthcarecoverageorextension.AcerisincomplianceinallmaterialrespectswithallapplicablerequirementsofthePatientProtectionandAffordableCareActof2010,asamended,andallregulationsthereunder(together,the“ACA”),includingallrequirementsrelatingtoeligibilitywaitingperiodsandtheofferoforprovisionofminimumessentialcoveragethatiscompliantwithSection36B(c)(2)(C)oftheCodeandtheregulationsissuedthereundertofull-timeemployeesasdefinedinSection4980H(c)(4)oftheCodeandtheregulationsissuedthereunder.NoexcisetaxorpenaltyundertheACA,includingSections4980Dand4980HoftheCode,isoutstanding,hasaccrued,orhasarisenwithrespecttoanyperiodpriortotheClosing,withrespecttoanyAcerEmployeePlan.NeitherAcernoranyAcerSubsidiaryhasanyunsatisfiedobligationstoanyemployeesorqualifiedbeneficiariespursuanttotheACA,oranystateorlocalLegalRequirementgoverninghealthcarecoverageorbenefitsthatwouldreasonablybeexpectedtoresultinanymaterialliabilitytoAcer.AcerandeachAcerSubsidiaryhasmaintainedallrecordsnecessarytodemonstrateitscompliancewiththeACA.

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(p) Acerisinmaterialcompliancewithallapplicableforeign,federal,stateandlocallaws,rules,regulations,orders,rulings,judgments,decreesorarbitrationawardsrespectingemployment,employmentpractices,termsandconditionsofemployment,workerclassification,taxwithholding,prohibiteddiscrimination,equalemployment,fairemploymentpractices,mealandrestperiods,immigrationstatus,employeesafetyandhealth,wages(includingovertimewages),compensation,hoursofwork,laborrelations,leaveofabsencerequirements,occupationalhealthandsafety,privacy,harassment,retaliation,immigrationandwrongfuldischargeandineachcase,withrespecttoemployees:(i)haswithheldandreportedallamountsrequiredbylaworbyagreementtobewithheldandreportedwithrespecttowages,salariesandotherpaymentstoemployees,(ii)isnotliableforanyarrearsofwages,severancepayoranyTaxesoranypenaltyofanymaterialamountforfailuretocomplywithanyoftheforegoing,and(iii)isnotliableforanypaymenttoanytrustorotherfundgovernedbyormaintainedbyoronbehalfofanyGovernmentalBody,withrespecttounemploymentcompensationbenefits,socialsecurityorotherbenefitsorobligationsforemployees(otherthanroutinepaymentstobemadeinthenormalcourseofbusinessandconsistentwithpastpractice).Therearenoactions,suits,claimsoradministrativematterspending,ortotheKnowledgeofAcer,threatenedorreasonablyanticipatedagainstAcerrelatingtoanyemployee,employmentagreement,independentcontractor,independentcontractoragreementorAcerEmployeePlan.Therearenopendingor,totheKnowledgeofAcer,threatenedorreasonablyanticipatedclaimsoractionsagainstAceroranyAcertrusteeunderanyworker’scompensationpolicyorlong-termdisabilitypolicy.Acerisnotpartytoaconciliationagreement,consentdecreeorotheragreementororderwithanyfederal,stateorlocalagencyorgovernmentalauthoritywithrespecttoemploymentpractices.

(q) NocurrentorformerindependentcontractorofAcerwouldreasonablybedeemedtobeamisclassifiedemployee.Acerdoesnothaveanymaterialliabilitywithrespecttoanymisclassificationof:(A)anyPersonasanindependentcontractorratherthanasanemployee,(B)anyemployeeleasedfromanotheremployeror(C)anyemployeecurrentlyorformerlyclassifiedasexemptfromovertimewages.Acerhasnottakenanyactionwhichwouldconstitutea“plantclosing”or“masslayoff”withinthemeaningoftheWARNActorsimilarstateorlocallaw,issuedanynotificationofaplantclosingormasslayoffrequiredbytheWARNActorsimilarstateorlocallaw,orincurredanyliabilityorobligationunderWARNoranysimilarstateorlocallawthatremainsunsatisfied.NoterminationsofemployeesofAcerpriortotheClosingwouldtriggeranynoticeorotherobligationsundertheWARNActorsimilarstateorlocallaw.

(r) ExceptassetforthinSection2.14(r)oftheAcerDisclosureSchedule,noneoftheexecutionanddeliveryofthisAgreement,ortheconsummationoftheContemplatedTransactionsoranyterminationofemploymentorserviceoranyothereventinconnectiontherewithorsubsequenttheretowill,individuallyortogetherorwiththeoccurrenceofsomeotherevent,(i)resultinanypayment(includingseverance,unemploymentcompensation,goldenparachute,bonusorotherwise)becomingduetoanyemployee,independentcontractorordirectorofAcer,(ii)materiallyincreaseorotherwiseenhanceanybenefitsotherwisepayablebyAcer,(iii)resultintheaccelerationofthetimeofpaymentorvestingofanysuchbenefits,exceptasrequiredunderSection411(d)(3)oftheCode,(iv)increasetheamountofcompensationduetoanyPersonbyAceror(v)resultintheforgivenessinwholeorinpartofanyoutstandingloansmadebyAcertoanyPerson.

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(s) WithrespecttoeachAcerEmployeePlan,AcerhasmadeavailabletoOpexaatrueandcompletecopyof,totheextentapplicable,(i)suchAcerEmployeePlan,(ii)thethreemostrecentannualreports(Form5500)asfiledwiththeInternalRevenueService,(iii)eachcurrentlyeffectivetrustagreementrelatedtosuchAcerEmployeePlan,(iv)themostrecentsummaryplandescriptionforeachAcerEmployeePlanforwhichsuchdescriptionisrequired,alongwithallsummariesofmaterialmodifications,amendments,resolutionsandallothermaterialplandocumentationrelatedtheretointhepossessionofAcer,and(v)themostrecentInternalRevenueServicedeterminationoropinionletteroranalogousrulingunderforeignlawissuedwithrespecttoanyAcerEmployeePlan.

2.15 Environmental Matters .AcerisinmaterialcompliancewithallapplicableEnvironmentalLaws,whichcomplianceincludesthepossessionbyAcerofallpermitsandotherGovernmentalAuthorizationsrequiredunderapplicableEnvironmentalLawsandcompliancewiththetermsandconditionsthereofotherthananyfailuretobeincomplianceorpossessanysuchpermitsandauthorizedthatisnotanAcerMaterialAdverseEffect.AcerhasnotreceivedsinceJanuary1,2011anywrittennoticeorothercommunication(inwritingorotherwise),whetherfromaGovernmentalBody,citizensgroup,employeeorotherwise,thatallegesthatAcerisnotincompliancewithanyEnvironmentalLaw,and,totheKnowledgeofAcer,therearenocircumstancesthatmaypreventorinterferewithAcer’scompliancewithanyEnvironmentalLawinthefuture.TotheKnowledgeofAcer:(i)nocurrentorpriorownerofanypropertyleasedorcontrolledbyAcerhasreceivedsinceJanuary1,2011anywrittennoticeorothercommunicationrelatingtopropertyownedorleasedatanytimebyAcer,whetherfromaGovernmentalBody,citizensgroup,employeeorotherwise,thatallegesthatsuchcurrentorpriorownerorAcerisnotincompliancewithorhasviolatedanyEnvironmentalLawrelatingtosuchpropertyand(ii)itdoesnothaveanymaterialliabilityunderanyEnvironmentalLaw.

2.16 Insurance.

(a) AcerhasdeliveredormadeavailabletoOpexaaccurateandcompletecopiesofallmaterialinsurancepoliciesandallmaterialself-insuranceprogramsandarrangementsrelatingtothebusiness,assets,liabilitiesandoperationsofAcer,asofthedateofthisAgreement.EachofsuchinsurancepoliciesisinfullforceandeffectandAcerisincompliancewiththetermsthereof.AsofthedateofthisAgreement,otherthancustomaryendofpolicynotificationsfrominsurancecarriers,sinceJanuary1,2011,Acerhasnotreceivedanynoticeorothercommunicationregardinganyactualorpossible:(a)cancelationorinvalidationofanyinsurancepolicy;(b)refusalordenialofanycoverage,reservationofrightsorrejectionofanymaterialclaimunderanyinsurancepolicy;or(c)materialadjustmentintheamountofthepremiumspayablewithrespecttoanyinsurancepolicy.Thereisnopendingworkers’compensationorotherclaimunderorbaseduponanyinsurancepolicyofAcer.Informationprovidedtoinsurancecarriers(inapplicationsandotherwise)onbehalfofAcerisaccurateandcomplete.Acerhasprovidedtimelywrittennoticetotheappropriateinsurancecarrier(s)ofeachLegalProceedingpendingorthreatenedagainstAcer,andnosuchcarrierhasissuedadenialofcoverageorareservationofrightswithrespecttoanysuchLegalProceeding,orinformedAcerofitsintenttodoso.

(b) AcerhasdeliveredtoOpexaaccurateandcompletecopiesoftheexistingpolicies(primaryandexcess)ofdirectors’andofficers’liabilityinsurancemaintainedbyAceras

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ofthedateofthisAgreement(the“ExistingAcerD&OPolicies”).Section2.16(b)oftheAcerDisclosureScheduleaccuratelysetsforth,asofthedateofthisAgreement,themostrecentannualpremiumspaidbyAcerwithrespecttotheExistingAcerD&OPolicies.AllpremiumsfortheExistingAcerD&OPolicieshavebeenpaidasofthedatehereof.

2.17 Legal Proceedings; Orders.

(a) ThereisnopendingLegalProceeding,and,totheKnowledgeofAcer,noPersonhasthreatenedinwritingtocommenceanyLegalProceeding:(i)thatinvolvesAcer,ortotheKnowledgeofAcer,anydirectororofficerofAcer(inhisorhercapacityassuch)oranyofthematerialassetsownedorusedbyAcer;or(ii)thatchallenges,orthatwouldreasonablybeexpectedtohavetheeffectofpreventing,delaying,makingillegalorotherwiseinterferingwith,theContemplatedTransactions.TotheKnowledgeofAcer,noeventhasoccurred,andnoclaim,disputeorotherconditionorcircumstanceexists,thatwill,orthatwouldreasonablybeexpectedto,giverisetoorserveasabasisforthecommencementofanysuchLegalProceeding.

(b) Thereisnoorder,writ,injunction,judgmentordecreetowhichAcer,oranyofthematerialassetsownedorusedbyAcer,issubject.TotheKnowledgeofAcer,noofficerofAcerissubjecttoanyorder,writ,injunction,judgmentordecreethatprohibitssuchofficerofAcerfromengaginginorcontinuinganyconduct,activityorpracticerelatingtothebusinessofAcerortoanymaterialassetsownedorusedbyAcer.

2.18 Inapplicability of Anti-Takeover Statutes .TheAcerBoardofDirectorshastakenandwilltakeallactionsnecessarytoensurethattherestrictionsapplicabletobusinesscombinationscontainedinSection203oftheDGCLare,andwillbe,inapplicabletotheexecution,deliveryandperformanceofthisAgreementandtheAcerStockholderSupportAgreementsandtotheconsummationoftheContemplatedTransactions.NootherstatetakeoverstatuteorsimilarLegalRequirementappliesorpurportstoapplytotheMerger,thisAgreement,theAcerStockholderSupportAgreementsoranyoftheotherContemplatedTransactions,ineachcaseduetothefactthatAcerisapartytosuchmatters.

2.19 No Financial Advisor .Nobroker,finderorinvestmentbankerisentitledtoanybrokeragefee,finder’sfee,opinionfee,successfee,transactionfeeorotherfeeorcommissioninconnectionwiththeContemplatedTransactionsbaseduponarrangementsmadebyoronbehalfofAcer.

2.20 Subscription Agreement .TheSubscriptionAgreementhasnotbeenamendedormodifiedinanymanner.NeitherAcernor,totheKnowledgeofAcer,anyofitsAffiliateshasenteredintoanyagreement,sideletterorotherarrangementrelatingtotheAcerPre-ClosingFinancing,orthetransactionscontemplatedbytheSubscriptionAgreement,otherthanassetforthintheSubscriptionAgreement.TherespectiveobligationsandagreementscontainedintheSubscriptionAgreementhavenotbeenwithdrawnorrescindedinanyrespect.TheSubscriptionAgreementisinfullforceandeffectandrepresentsavalid,bindingandenforceableobligationofAcerand,totheKnowledgeofAcer,ofeachotherpartythereto,subjecttothequalificationthatsuchenforceabilitymaybelimitedbybankruptcy,insolvency,reorganizationorotherlawsofgeneralapplicationrelatingtooraffectingrightsofcreditors.Noeventhasoccurredwhich,withorwithoutnotice,lapseoftimeorboth,wouldconstituteabreachordefaultonthepartof

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Aceror,totheKnowledgeofAcer,anyotherpartythereto,undertheSubscriptionAgreement.TotheKnowledgeofAcer,nopartytheretowillbeunabletosatisfyonatimelybasisanytermoftheSubscriptionAgreement.TherearenoconditionsprecedentrelatedtotheconsummationoftheAcerPre-ClosingFinancingcontemplatedbytheSubscriptionAgreement,otherthanthesatisfactionorwaiveroftheconditionsexpresslysetforthinArticle5oftheSubscriptionAgreement.TotheKnowledgeofAcer,thefundsfromtheAcerPre-ClosingFinancingwillbemadeavailabletoAcerpriortotheconsummationoftheMerger.

2.21 Disclosure .TheinformationsuppliedbyAcerforinclusionintheProxyStatement/Prospectus/InformationStatement(includinganyAcerFinancials)willnot,asofthedateoftheProxyStatement/Prospectus/InformationStatementorasofthedatesuchinformationisfirstmailedtoOpexaShareholders,(i)containanyuntruestatementofanymaterialfactor(ii)omittostateanymaterialfactnecessaryinordertomakesuchinformation,inthelightofthecircumstancesunderwhichsuchinformationisprovided,notfalseormisleading.

2.22 Exclusivity of Representations; Reliance.

(a) ExceptasexpresslysetforthinthisArticle2,neitherAcernoranyPersononbehalfofAcerhasmade,norareanyofthemmaking,anyrepresentationorwarranty,writtenororal,expressorimplied,atlaworinequity,includingwithrespecttomerchantabilityorfitnessforanyparticularpurpose,inrespectofAceroritsbusinessinconnectionwiththetransactionscontemplatedhereby,includinganyrepresentationsorwarrantiesabouttheaccuracyorcompletenessofanyinformationordocumentspreviouslyprovided(includingwithrespecttoanyfinancialorotherprojectionstherein),andanyothersuchrepresentationsandwarrantiesareherebyexpresslydisclaimed.

(b) Aceracknowledgesandagreesthat,exceptfortherepresentationsandwarrantiesofOpexaandMergerSubsetforthinArticle3,neitherAcernoritsRepresentativesisrelyingonanyotherrepresentationorwarrantyofOpexa,MergerSub,oranyotherPersonmadeoutsideofArticle3ofthisAgreement,includingregardingtheaccuracyorcompletenessofanysuchotherrepresentationsorwarrantiesortheomissionofanymaterialinformation,whetherexpressorimplied,ineachcasewithrespecttotheContemplatedTransactions.

ARTICLE 3

REPRESENTATIONS AND WARRANTIES OF OPEXA AND MERGER SUB

OpexaandMergerSubrepresentandwarranttoAcerasfollows,exceptassetforthinthewrittendisclosurescheduledeliveredbyOpexatoAcer(the“OpexaDisclosureSchedule” )(itbeingunderstoodthattherepresentationsandwarrantiesinthisArticle3arequalifiedby:(a)anyexceptionsanddisclosuressetforthinthesectionorsubsectionoftheOpexaDisclosureSchedulecorrespondingtotheparticularsectionorsubsectioninthisArticle3inwhichsuchrepresentationandwarrantyappears;(b)anyexceptionsordisclosuresexplicitlycross-referencedinsuchsectionorsubsectionoftheOpexaDisclosureSchedulebyreferencetoanothersectionorsubsectionoftheOpexaDisclosureSchedule;and(c)anyexceptionsordisclosuressetforthinanyothersectionorsubsectionoftheOpexaDisclosureScheduletothe

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extentitisreasonablyapparentonthefaceofsuchexceptionordisclosurethatsuchexceptionordisclosurequalifiessuchrepresentationandwarranty).TheinclusionofanyinformationintheOpexaDisclosureScheduleshallnotbedeemedtobeanadmissionoracknowledgement,inandofitself,thatsuchinformationisrequiredbythetermshereoftobedisclosed,ismaterial,hasresultedinorwouldresultinanOpexaMaterialAdverseEffect,orisoutsidetheOrdinaryCourseofBusiness.

3.1 Subsidiaries; Due Organization; Organizational Documents.

(a) OtherthanMergerSuborassetforthinSection3.1(a)oftheOpexaDisclosureSchedule(suchSubsidiaries,alongwithMergerSub,the“OpexaSubsidiaries”),OpexadoesnothaveanySubsidiariesandOpexadoesnotownanycapitalstockof,oranyequityinterestofanynaturein,anyotherEntity.Opexahasneitheragreednorisobligatedtomake,norisboundbyanyContractunderwhichitmaybecomeobligatedtomake,anyfutureinvestmentinorcapitalcontributiontoanyotherEntity.Opexahasnot,atanytime,beenageneralpartnerof,orotherwisebeenliableforanyofthedebtsorotherobligationsof,anygeneralpartnership,limitedpartnershiporotherEntity.

(b) EachofOpexaandtheOpexaSubsidiariesisacorporationorlimitedliabilitycompany,asapplicable,dulyorganized,validlyexistingandingoodstandingunderthelawsofthejurisdictionofitsformation/incorporationandhasallnecessarypowerandauthority:(i)toconductitsbusinessinthemannerinwhichitsbusinessiscurrentlybeingconducted;(ii)toownanduseitsassetsinthemannerinwhichitsassetsarecurrentlyownedandused;and(iii)toperformitsobligationsunderallOpexaContracts.

(c) EachofOpexaandtheOpexaSubsidiariesisqualifiedtodobusinessasaforeigncorporation,andisingoodstanding,underthelawsofalljurisdictionswherethenatureofitsbusinessrequiressuchqualificationotherthaninjurisdictionswherethefailuretobesoqualifiedwouldnotconstituteanOpexaMaterialAdverseEffect.

(d) EachdirectorandofficerofOpexaandMergerSubasofthedateofthisAgreementissetforthinSection3.1(d)oftheOpexaDisclosureSchedule.

(e) MergerSubwasformedsolelyforthepurposeofengagingintheContemplatedTransactions.ExceptforobligationsandliabilitiesincurredinconnectionwithitsincorporationandtheContemplatedTransactions,MergerSubhasnot,andwillnothave,incurred,directlyorindirectly,anyobligationsorliabilitiesorengagedinanybusinessactivitiesofanytypeorkindwhatsoeverorenteredintoanyagreementsorarrangementswithanyPerson.

(f) OpexahasdeliveredormadeavailabletoAceraccurateandcompletecopiesof(i)thecertificateofformation/incorporation,bylawsandothercharterandorganizationaldocuments,includingallcurrentlyeffectiveamendmentsthereto,forOpexaandMergerSub;and(ii)anycodeofconductorsimilarpolicyadoptedbyOpexaorbytheOpexaBoardofDirectorsoranycommitteethereof.NeitherOpexanorMergerSubisinmaterialviolationofanyoftheprovisionsofitsrespectiveorganizationaldocuments.

3.2 Authority; Vote Required.

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(a) EachofOpexaandMergerSubhasallnecessarycorporatepowerandauthoritytoenterintoand,subjecttotheRequiredOpexaShareholderVoteandtheRequiredMergerSubStockholderVote,asapplicabletoperformitsobligationsunderthisAgreement.TheOpexaBoardofDirectorshas:(i)determinedthattheMergerisfairto,andinthebestinterestsof,OpexaandOpexaShareholders;(ii)dulyauthorizedandapprovedbyallnecessarycorporateaction,theexecution,deliveryandperformanceofthisAgreementandtheContemplatedTransactions;(iii)recommendedtheapprovaloftheOpexaShareholderMattersbytheOpexaShareholdersanddirectedthattheOpexaShareholderMattersbesubmittedforconsiderationbyOpexaShareholdersinconnectionwiththesolicitationoftheRequiredOpexaShareholderVote;and(iv)approvedtheOpexaShareholderSupportAgreementsandthetransactionscontemplatedthereby.TheboardofdirectorsofMergerSubhas(A)determinedthattheMergerisfairto,andinthebestinterestsof,MergerSubanditssolestockholder;(B)dulyauthorizedandapprovedbyallnecessarycorporateaction,theexecution,deliveryandperformanceofthisAgreementandtheContemplatedTransactions;and(C)recommendedthatthesolestockholderofMergerSubadoptthisAgreementandtherebyapprovetheMergerandtheapplicableContemplatedTransactions.ThisAgreementhasbeendulyexecutedanddeliveredbyOpexaandMergerSuband,assumingthedueauthorization,executionanddeliverybyAcer,constitutesthelegal,validandbindingobligationofOpexaandMergerSub,enforceableagainstOpexaandMergerSubinaccordancewithitsterms,subjectto:(1)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtors;and(2)rulesoflawgoverningspecificperformance,injunctivereliefandotherequitableremedies.

(b) (i)TheaffirmativevoteoftheholdersofamajorityofoutstandingsharesofOpexaCommonStockistheonlyvoteoftheholdersofanyclassorseriesofOpexaCapitalStocknecessarytoapprovetheOpexaShareholderMatters(the“RequiredOpexaShareholderVote”)and(ii)theaffirmativevoteofthesolestockholderofMergerSubistheonlyvoteoftheholdersofanyclassorseriesofMergerSubCapitalStocknecessarytoadoptthisAgreementandapprovetheMergerandtheapplicableContemplatedTransactions(the“RequiredMergerSubStockholderVote”).

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3.3 Non-Contravention; Consents.

(a) TheexecutionanddeliveryofthisAgreementbyOpexadoesnot,andtheperformanceofthisAgreementbyOpexaandMergerSubwillnot,(i)conflictwithorviolatethecertificateofformation/incorporationorbylawsofOpexaoranyOpexaSubsidiaries;(ii)subjecttoobtainingtheRequiredOpexaShareholderVoteandtheRequiredMergerSubStockholderVoteandcompliancewiththerequirementssetforthinSection3.3(b)below,conflictwithorviolateanyLegalRequirementapplicabletoOpexaoranyOpexaSubsidiariesorbywhichitsoranyoftheirrespectivepropertiesareboundoraffected,exceptforanysuchconflictsorviolationsthatwouldnotconstituteanOpexaMaterialAdverseEffect;or(iii)requireOpexaoranyOpexaSubsidiariestomakeanyfilingwithorgiveanynoticetoaPersonormakeanypayment,orobtainanyConsentfromaPerson,orresultinanybreachoforconstituteadefault(oraneventthatwithnoticeorlapseoftimeorbothwouldbecomeadefault)under,orimpairOpexa’soranyOpexaSubsidiary’srightsoraltertherightsorobligationsofanythirdpartyunder,orgivetoothersanyrightsoftermination,amendment,accelerationorcancelationof,orresultinthecreationofanEncumbranceonanyofthepropertiesorassetsofOpexaorMergerSubpursuantto,anyOpexaMaterialContract.

(b) NomaterialConsent,orderof,orregistration,declarationorfilingwithanyGovernmentalBodyisrequiredbyorwithrespecttoOpexaorMergerSubinconnectionwiththeexecutionanddeliveryofthisAgreementortheconsummationoftheContemplatedTransactions,exceptfor(i)thefilingoftheCertificateofMergerwiththeSecretaryofStateoftheStateofDelawarepursuanttotheDGCL,(ii)anyrequiredfilingsundertheHSRActandanyforeignantitrustLegalRequirementand(iii)suchConsents,orders,registrations,declarationsandfilingsasmayberequiredunderapplicablefederalandstatesecuritieslaws.

3.4 Capitalization.

(a) TheauthorizedcapitalstockofOpexaasofthedateofthisAgreementconsistsof:(i)150,000,000sharesofsharesofcommonstock,parvalue$0.01pershare(the“OpexaCommonStock”),ofwhich7,657,332sharesareissuedandoutstandingasofthedateofthisAgreement,and(ii)10,000,000sharesofpreferredstock,noparvalue,ofwhichnosharesareoutstandingasofthedateofthisAgreement.AlloftheissuedandoutstandingsharesofOpexaCommonStockhavebeendulyauthorizedandvalidlyissued,andarefullypaidandnonassessable.AsofthedateofthisAgreement,thereareoutstandingOpexaWarrantstopurchase3,468,731sharesofOpexaCommonStock.Section3.4(a)oftheOpexaDisclosureSchedulelists,asofthedateofthisAgreement(A)eachrecordholderofissuedandoutstandingOpexaCommonStockandthenumberofsharesofOpexaCommonStockheldbyeachsuchrecordholderand(B)(1)eachholderofissuedandoutstandingOpexaWarrants,(2)thenumberandtypeofsharessubjecttosuchOpexaWarrants,(3)theexercisepriceofeachsuchOpexaWarrant,and(4)theterminationdateofeachsuchOpexaWarrant.

(b) ExceptfortheOpexaAmendedandRestated2010StockIncentivePlan,whichisthesuccessortoandcontinuationofOpexa’sJune2004CompensatoryStockOptionPlan(collectively,the“2010Plan”),Opexadoesnothaveanystockoptionplanoranyotherplan,program,agreementorarrangementprovidingforanyequity-basedcompensationforanyPerson.Opexahasreserved1,175,000sharesofOpexaCommonStockforissuanceunderthe

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2010Plan.AsofthedateofthisAgreement,ofsuchreservedsharesofOpexaCommonStock,(i)7,722shareshavebeenissuedpursuanttotheexerciseofoptionsandoptionstopurchase228,455shareshavebeengrantedandarecurrentlyoutstanding,(ii)116,524shareshavebeenissuedpursuanttorestrictedstockawards,and(iii)822,299sharesofOpexaCommonStockremainavailableforfutureissuancepursuanttothe2010Plan.Section3.4(b)oftheOpexaDisclosureSchedulesetsforththefollowinginformation(A)withrespecttoeachOpexaOptionoutstandingasofthedateofthisAgreement:(1)thenameoftheoptionee,(2)thenumberofsharesofOpexaCommonStocksubjecttosuchOpexaOptionasofthedateofthisAgreement,(3)theexercisepriceofsuchOpexaOption,(4)thedateonwhichsuchOpexaOptionwasgranted,(5)thedateonwhichsuchOpexaOptionexpires,and(6)thevestingscheduleapplicabletosuchOpexaOption,includingtheextentvestedtodateandwhetherbyitstermsthevestingofsuchOpexaOptionwouldbeacceleratedbytheContemplatedTransactions;and(B)withrespecttoeachOpexaRSUoutstandingasofthedateofthisAgreement:(1)thenameoftheholder,(2)thevestingtermsofeachsuchOpexaRSU,(3)thedateonwhicheachsuchOpexaRSUwasgranted,(4)thedateonwhicheachsuchOpexaRSUexpires,and(5)thevestingscheduleapplicabletosuchOpexaRSU,includingtheextentvestedtodateandwhetherbyitstermsthevestingofsuchOpexaRSUwouldbeacceleratedbytheContemplatedTransactions.

(c) ExceptfortheoutstandingOpexaWarrantssetforthonSection3.4(a)oftheOpexaDisclosureScheduleandfortheOpexaOptionsandOpexaRSUssetforthonSection3.4(b)oftheOpexaDisclosureSchedule,thereisno:(i)outstandingsubscription,option,call,warrantorright(whetherornotcurrentlyexercisable)toacquireanysharesofthecapitalstockorothersecuritiesofOpexaorMergerSub;(ii)outstandingsecurity,instrumentorobligationthatisormaybecomeconvertibleintoorexchangeableforanysharesofthecapitalstockorothersecuritiesofOpexaorMergerSub;(iii)stockholderrightsplan(orsimilarplancommonlyreferredtoasa“poisonpill”)orContractunderwhichOpexaorMergerSubisormaybecomeobligatedtosellorotherwiseissueanysharesofitscapitalstockoranyothersecurities;or(iv)conditionorcircumstancethatmaygiverisetoorprovideabasisfortheassertionofaclaimbyanyPersontotheeffectthatsuchPersonisentitledtoacquireorreceiveanysharesofcapitalstockorothersecuritiesofOpexaorMergerSub.Therearenooutstandingorauthorizedstockappreciation,phantomstock,profitparticipation,restrictedstockunits,equity-basedawardsorothersimilarrightswithrespecttoOpexaorMergerSub.

(d) ExceptassetforthinSection3.4(d)oftheOpexaDisclosureSchedule,(i)noneoftheoutstandingsharesofOpexaCapitalStockorMergerSubCapitalStockareentitledorsubjecttoanypreemptiveright,rightofrepurchaseorforfeiture,rightofparticipation,rightofmaintenanceoranysimilarright;(ii)noneoftheoutstandingsharesofOpexaCapitalStockorMergerSubCapitalStockaresubjecttoanyrightoffirstrefusalinfavorofOpexaorMergerSub,asapplicable;(iii)therearenooutstandingbonds,debentures,notesorotherindebtednessofOpexaorMergerSubhavingarighttovoteonanymattersonwhichtheOpexaShareholdersorthesolestockholderofMergerSub,asapplicable,havearighttovote;(iv)thereisnoOpexaContracttowhichOpexaorMergerSubareapartyrelatingtothevotingorregistrationof,orrestrictinganyPersonfrompurchasing,selling,pledgingorotherwisedisposingof(orfromgrantinganyoptionorsimilarrightwithrespectto),anysharesofOpexaCapitalStockorMergerSubCapitalStock.NeitherOpexanorMergerSubisunderanyobligation,norisboundbyanyContractpursuanttowhichitmaybecomeobligated,torepurchase,redeemorotherwise

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acquireanyoutstandingsharesofOpexaCapitalStock,MergerSubCapitalStockorothersecurities.

(e) TheauthorizedcapitalofMergerSubconsistsof1,000sharesofcommonstock,parvalue$0.0001pershare(“MergerSubCapitalStock”),allofwhichare,andattheEffectiveTimewillbe,issuedandoutstandingandheldofrecordbyOpexa.TheissuedandoutstandingsharesofMergerSubCapitalStockaredulyauthorized,validlyissued,fullypaidandnonassessable.MergerSubhasnotatanytimegrantedanystockoptions,restrictedstock,phantomstock,profitparticipation,restrictedstockunits,equity-basedawardsorothersimilarrights.

(f) AlloutstandingsharesofOpexaCapitalStockandMergerSubCapitalStock,aswellasallOpexaOptions,allOpexaRSUsandallOpexaWarrants,havebeenissuedandgranted,asapplicable,inmaterialcompliancewithallapplicablesecuritieslawsandotherapplicableLegalRequirements.

3.5 SEC Filings; Financial Statements.

(a) OpexahasmadeavailabletoAceraccurateandcompletecopiesofallregistrationstatements,proxystatements,Certifications(asdefinedbelow)andotherstatements,reports,schedules,formsandotherdocumentsfiledbyOpexawiththeSECsinceJanuary1,2014(the“ OpexaSECDocuments” ),otherthansuchdocumentsthatcanbeobtainedontheSEC’swebsiteatwww.sec.gov.Allstatements,reports,schedules,formsandotherdocumentsrequiredtohavebeenfiledbyOpexaoritsofficerswiththeSEChavebeensofiledonatimelybasis.AsofthetimeitwasfiledwiththeSEC(or,ifamendedorsupersededbyafilingpriortothedateofthisAgreement,thenonthedateofsuchfiling),eachoftheOpexaSECDocumentscompliedinallmaterialrespectswiththeapplicablerequirementsoftheSecuritiesActortheExchangeAct(asthecasemaybe)and,asofthetimetheywerefiled,noneoftheOpexaSECDocumentscontainedanyuntruestatementofamaterialfactoromittedtostateamaterialfactrequiredtobestatedthereinornecessaryinordertomakethestatementstherein,inthelightofthecircumstancesunderwhichtheyweremade,notmisleading.Thecertificationsandstatementsrequiredby(A)Rule13a-14undertheExchangeActand(B)18U.S.C.§1350(Section906oftheSarbanes-OxleyAct)relatingtotheOpexaSECDocuments(collectively,the“ Certifications” )areaccurateandcompleteandcomplyastoformandcontentwithallapplicableLegalRequirements.AsusedinthisArticle3,theterm“file”andvariationsthereofshallbebroadlyconstruedtoincludeanymannerinwhichadocumentorinformationisfurnished,suppliedorotherwisemadeavailabletotheSEC.

(b) Thefinancialstatements(includinganyrelatednotes)containedorincorporatedbyreferenceintheOpexaSECDocuments:(i)compliedastoforminallmaterialrespectswiththepublishedrulesandregulationsoftheSECapplicablethereto;(ii)werepreparedinaccordancewithGAAP(exceptasmaybeindicatedinthenotestosuchfinancialstatementsor,inthecaseofunauditedfinancialstatements,aspermittedbyForm10-QoftheSEC,andexceptthattheunauditedfinancialstatementsmaynotcontainfootnotesandaresubjecttonormalandrecurringyear-endadjustmentsthatarenotreasonablyexpectedtobematerialinamount)appliedonaconsistentbasisunlessotherwisenotedthereinthroughouttheperiodsindicated;and(iii)fairlypresenttheconsolidatedfinancialpositionofOpexaasofthe

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respectivedatesthereofandtheresultsofoperationsandcashflowsofOpexafortheperiodscoveredthereby.OtherthanasexpresslydisclosedintheOpexaSECDocumentsfiledpriortothedatehereof,therehasbeennomaterialchangeinOpexa’saccountingmethodsorprinciplesthatwouldberequiredtobedisclosedinOpexa’sfinancialstatementsinaccordancewithGAAP.ThebooksofaccountandotherfinancialrecordsofOpexaaretrueandcompleteinallmaterialrespects.

(c) Opexa’sauditorhasatalltimessincethedateofenactmentoftheSarbanes-OxleyActbeen:(i)aregisteredpublicaccountingfirm(asdefinedinSection2(a)(12)oftheSarbanes-OxleyAct);(ii)totheKnowledgeofOpexa,“independent”withrespecttoOpexawithinthemeaningofRegulationS-XundertheExchangeAct;and(iii)totheKnowledgeofOpexa,incompliancewithsubsections(g)through(l)ofSection10AoftheExchangeActandtherulesandregulationspromulgatedbytheSECandthePublicOpexaAccountingOversightBoardthereunder.

(d) ExceptassetforthinSection3.5(d)oftheOpexaDisclosureSchedule,fromJanuary1,2014throughthedatehereof,OpexahasnotreceivedanycommentletterfromtheSECorthestaffthereoforanycorrespondencefromNASDAQorthestaffthereofrelatingtothedelistingormaintenanceoflistingoftheOpexaCommonStockonTheNASDAQCapitalMarket.OpexahasnotdisclosedanyunresolvedcommentsinitsSECDocuments.TotheKnowledgeofOpexa,noneoftheOpexaSECDocumentsarethesubjectofongoingSECrevieworoutstandingSECinvestigationandtherearenooutstandingorunresolvedcommentsreceivedfromtheSECwithrespecttoanyoftheOpexaSECDocuments.

(e) SinceJanuary1,2011,therehavebeennoformalinternalinvestigationsregardingfinancialreportingoraccountingpoliciesandpracticesdiscussedwith,reviewedbyorinitiatedatthedirectionofthechiefexecutiveofficerorchieffinancialofficerofOpexa,theOpexaBoardofDirectorsoranycommitteethereof,otherthanordinarycourseauditsorreviewsofaccountingpoliciesandpracticesorinternalcontrolsrequiredbytheSarbanes-OxleyAct.

(f) OpexaisincomplianceinallmaterialrespectswiththeapplicableprovisionsoftheSarbanes-OxleyActandtheapplicablelistingandgovernancerulesandregulationsofTheNASDAQCapitalMarket.

(g) Opexamaintainsasystemofinternalcontroloverfinancialreporting(asdefinedinRules13a-15(f)and15d-15(f)oftheExchangeAct)thatissufficienttoprovidereasonableassuranceregardingthereliabilityoffinancialreportingandthepreparationoffinancialstatementsforexternalpurposesinaccordancewithGAAP,includingpoliciesandproceduressufficienttoprovidereasonableassurance(i)thatOpexamaintainsrecordsthatinreasonabledetailaccuratelyandfairlyreflectOpexa’stransactionsanddispositionsofassets,(ii)thattransactionsarerecordedasnecessarytopermitpreparationoffinancialstatementsinaccordancewithGAAP,(iii)thatreceiptsandexpendituresaremadeonlyinaccordancewithauthorizationsofmanagementandtheOpexaBoardofDirectors,and(iv)regardingpreventionortimelydetectionoftheunauthorizedacquisition,useordispositionofOpexa’sassetsthatcouldhaveamaterialeffectonOpexa’sfinancialstatements.OpexahasevaluatedtheeffectivenessofOpexa’sinternalcontroloverfinancialreportingand,totheextentrequiredbyapplicableLegalRequirements,presentedinanyapplicableOpexaSECDocumentthatisa

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reportonForm10-KorForm10-Q(oranyamendmentthereto)itsconclusionsabouttheeffectivenessoftheinternalcontroloverfinancialreportingasoftheendoftheperiodcoveredbysuchreportoramendmentbasedonsuchevaluation.OpexahasdisclosedtoOpexa’sauditorsandtheAuditCommitteeoftheOpexaBoardofDirectors(andmadeavailabletoAcerasummaryofthesignificantaspectsofsuchdisclosure)(A)allsignificantdeficienciesandmaterialweaknessesinthedesignoroperationofinternalcontroloverfinancialreportingthatarereasonablylikelytoadverselyaffectOpexa’sabilitytorecord,process,summarizeandreportfinancialinformationand(B)anyfraud,whetherornotmaterial,thatinvolvesmanagementorotheremployeeswhohaveasignificantroleinOpexa’sinternalcontroloverfinancialreporting.ExceptasdisclosedintheOpexaSECDocumentsfiledpriortothedatehereof,OpexahasnotidentifiedanymaterialweaknessesinthedesignoroperationofOpexa’sinternalcontroloverfinancialreporting.SinceJanuary1,2014,therehavebeennomaterialchangesinOpexa’sinternalcontroloverfinancialreporting.

(h) Opexa’s“disclosurecontrolsandprocedures”(asdefinedinRules13a-15(e)and15d-15(e)oftheExchangeAct)arereasonablydesignedtoensurethatallinformation(bothfinancialandnon-financial)requiredtobedisclosedbyOpexainthereportsthatitfilesorsubmitsundertheExchangeActisrecorded,processed,summarizedandreportedwithinthetimeperiodsspecifiedintherulesandformsoftheSEC,andthatallsuchinformationisaccumulatedandcommunicatedtoOpexa’smanagementasappropriatetoallowtimelydecisionsregardingrequireddisclosureandtomaketheCertifications.

3.6 Absence of Changes .ExceptassetforthinSection3.6oftheOpexaDisclosureSchedule,betweenMarch31,2017andthedateofthisAgreementOpexahasconducteditsbusinessintheOrdinaryCourseofBusinessandtherehasnotbeen(a)anyeventthathashadanOpexaMaterialAdverseEffectoranyevent,condition,change,oreffectthatcouldreasonablybeexpectedtohave,individuallyorintheaggregate,anOpexaMaterialAdverseEffector(b)anyaction,eventoroccurrencethatwouldhaverequiredconsentofAcerpursuanttoSection4.2(b)ofthisAgreementhadsuchaction,eventoroccurrencetakenplaceaftertheexecutionanddeliveryofthisAgreement.

3.7 Title to Assets .Opexaowns,andhasgoodandvalidtitleto,or,inthecaseofleasedpropertiesandassets,validleaseholdinterestsin,alltangiblepropertiesorassetsandequipmentusedorheldforuseinitsbusinessoroperationsorpurportedtobeownedbyit,ineachcase,freeandclearofanyEncumbrances,exceptfor:(i)anylienforcurrentTaxesnotyetdueandpayableorforTaxesthatarebeingcontestedingoodfaithandforwhichadequatereserveshavebeenmadeontheOpexaUnauditedInterimBalanceSheet;(ii)minorliensthathavearisenintheOrdinaryCourseofBusinessandthatdonot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheassetssubjecttheretoormateriallyimpairtheoperationsofOpexa;and(iii)lienslistedinSection3.7oftheOpexaDisclosureSchedule.

3.8 Real Property; Leaseholds .OpexadoesnotcurrentlyownnorhasitoranyofitsSubsidiarieseverownedanyrealpropertyoranyinterestinrealproperty,exceptfortheleaseholdscreatedundertherealpropertyleases(includinganyamendmentsthereof)identifiedinSection3.8oftheOpexaDisclosureSchedule(the“OpexaLeases”),whichareeachinfullforceandeffective,withnoexistingmaterialdefaultthereunder.Opexa’spossessionandquietenjoymentoftheleasedrealestateundersuchOpexaLeaseshasnotbeendisturbed,andtothe

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KnowledgeofOpexa,therearenodisputeswithrespecttosuchOpexaLeases.OpexahasnotcreatedanyEncumbrancesontherealestateundertheOpexaLeases.

3.9 Intellectual Property.

(a) Opexaowns,orhastherighttouse,andhastherighttobringactionsfortheinfringementof,allOpexaIPRights,exceptforanyfailuretoownorhavetherighttouse,orhavetherighttobringactionsthatwouldnotconstituteanOpexaMaterialAdverseEffect.

(b) Section3.9(b)oftheOpexaDisclosureScheduleisanaccurate,trueandcompletelistingofallOpexaRegisteredIP.

(c) Section3.9(c)oftheOpexaDisclosureScheduleaccuratelyidentifies(i)allOpexaIPRightslicensedtoOpexa(otherthan(A)anynon-customizedsoftwarethat(1)issolicensedsolelyinexecutableorobjectcodeformpursuanttoanon-exclusive,internalusesoftwarelicenseandotherIntellectualPropertyassociatedwithsuchsoftwareand(2)isnotincorporatedinto,ormaterialtothedevelopment,manufacturing,ordistributionof,anyofOpexa’sproductsorservicesand(B)anyIntellectualPropertylicensedancillarytothepurchaseoruseofequipment,reagentsorothermaterials);(ii)thecorrespondingOpexaContractspursuanttowhichsuchOpexaIPRightsarelicensedtoOpexa;(iii)whetherthelicenseorlicensesgrantedtoOpexaareexclusiveornon-exclusive;and(iv)whetheranyfunding,facilitiesorpersonnelofanyGovernmentalBodywereused,directlyorindirectly,todeveloporcreate,inwholeorinpart,suchOpexaIPRights.

(d) Section3.9(d)oftheOpexaDisclosureScheduleaccuratelyidentifieseachOpexaContractpursuanttowhichanyPerson(otherthanOpexa)hasbeengrantedanylicenseoroptiontoobtainalicenseunder,orotherwisehasreceivedoracquiredanyright(whetherornotcurrentlyexercisable)orinterestin,anyOpexaIPRights.Opexaisnotboundby,andnoOpexaIPRightsaresubjectto,anyContractcontaininganycovenantorotherprovisionthatinanywaylimitsorrestrictstheabilityofOpexatouse,exploit,assertorenforceanyOpexaIPRightsanywhereintheworld,ineachcaseaswouldmateriallylimitthebusinessofOpexaascurrentlyconductedorplannedtobeconducted.

(e) Opexasolelyownsallright,title,andinteresttoandinOpexaIPRights(otherthanOpexaIPRights(i)exclusivelyornon-exclusivelylicensedtoOpexa,asidentifiedinSection3.9(c)oftheOpexaDisclosureSchedule,(ii)anynon-customizedsoftwarethat(A)issolicensedsolelyinexecutableorobjectcodeformpursuanttoanon-exclusive,internalusesoftwarelicenseandotherIntellectualPropertyassociatedwithsuchsoftwareand(B)isnotincorporatedinto,ormaterialtothedevelopment,manufacturing,ordistributionof,anyofOpexa’sproductsorservices,and(iii)anyIntellectualPropertylicensedancillarytothepurchaseoruseofequipment,reagentsorothermaterials)freeandclearofanyEncumbrances.WithoutlimitingthegeneralityoftheforegoingandexceptassetforthinSection3.9(e)oftheOpexaDisclosureSchedule:

(i) AlldocumentsandinstrumentsnecessarytoregisterorapplyfororrenewregistrationofallOpexaRegisteredIPhavebeenvalidlyexecuted,deliveredandfiledinatimelymannerwiththeappropriateGovernmentalBodyexceptforanysuchfailure,individually

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orcollectively,thatwouldnot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheOpexaRegisteredIPsubjecttheretoormateriallyimpairtheoperationsofOpexa.

(ii) EachPersonwhoisorwasanemployeeorcontractorofOpexaandwhoisorwasinvolvedinthecreationordevelopmentofanyOpexaIPRightshassignedavalid,enforceableagreementcontaininganassignmentofsuchIntellectualPropertytoOpexaandconfidentialityprovisionsprotectingtradesecretsandconfidentialinformationofOpexa.TotheKnowledgeofOpexa,nocurrentorformershareholder,officer,director,employeeorcontractorofOpexaoranyofitsSubsidiarieshasanyclaim,right(whetherornotcurrentlyexercisable),orinteresttoorinanyOpexaIPRights.TotheKnowledgeofOpexa,noemployeeorcontractorofOpexais(a)boundbyorotherwisesubjecttoanyContractrestrictinghimorherfromperforminghisorherdutiesforOpexaor(b)inbreachofanyContractwithanycurrentorformeremployerorotherPersonconcerningOpexaIPRightsorconfidentialityprovisionsprotectingtradesecretsandconfidentialinformationcomprisingOpexaIPRights.

(iii) Nofunding,facilitiesorpersonnelofanyGovernmentalBodywereused,directlyorindirectly,todeveloporcreate,inwholeorinpart,anyOpexaIPRightsinwhichOpexahasanownershipinterest.

(iv) OpexahastakenreasonablestepstomaintaintheconfidentialityofandotherwiseprotectandenforceitsrightsinallproprietaryinformationthatOpexaholds,orpurportstohold,asatradesecret.

(v) Opexahasnotassignedorotherwisetransferredownershipof,oragreedtoassignorotherwisetransferownershipof,anyOpexaIPRightstoanyotherPerson,exceptforanysuchassignmentsortransfersmadeafterthedateofthisAgreementpursuanttoaPermittedOpexaAssetSale.

(vi) TheOpexaIPRightsconstituteallIntellectualPropertynecessaryforOpexatoconductitsbusinessascurrentlyconductedorplannedtobeconducted.

(f) OpexaisnotapartytoanyContractthat,asaresultoftheexecution,deliveryandperformanceofthisAgreementandtheconsummationoftheContemplatedTransactionswillcausethegrantofanylicenseorotherrighttoanyOpexaIPRightsormateriallyimpairtherightofOpexaortheSurvivingCorporationanditsSubsidiariestouse,sell,licenseorenforceanyOpexaIPRightsorportionthereof.

(g) Themanufacture,marketing,license,saleorintendeduseofanyproductorservicecurrentlyapprovedorsoldorunderpreclinicalorclinicaldevelopmentbyOpexa(i)doesnotviolateorconstituteabreachofanylicenseoragreementbetweenOpexaandanythirdparty,and,(ii)totheKnowledgeofOpexa,doesnotinfringeormisappropriateanyIntellectualPropertyrightofanyotherparty.OpexahasdisclosedincorrespondencetoAcerthethird-partypatentsandpatentapplicationsfoundduringallfreedomtooperatesearchesthatwereconductedbyOpexarelatedtoanyproductortechnologycurrentlyapprovedorsoldorunderpreclinicalorclinicaldevelopmentbyOpexa.TotheKnowledgeofOpexa,nothirdpartyisinfringinguponormisappropriating,orviolatinganylicenseoragreementwithOpexarelatingto,anyOpexaIPRights.Thereisnocurrentorpendingchallenge,claimorLegalProceeding(including

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opposition,interferenceorotherproceedinginanypatentorothergovernmentoffice)contestingthevalidity,enforceability,ownershiporrighttouse,sell,licenseordisposeofanyOpexaIPRights,norhasOpexareceivedanywrittennoticeassertingthatthemanufacture,marketing,license,saleorintendeduseofanyproductorservicecurrentlyapprovedorsoldorunderpreclinicalorclinicaldevelopmentbyOpexaconflictswithorinfringesormisappropriatesorwillconflictwithorinfringeormisappropriatetherightsofanyotherPerson.

(h) EachitemofOpexaIPRightsthatisOpexaRegisteredIPisandatalltimeshasbeenfiledandmaintainedincompliancewithallapplicableLegalRequirementsandallfilings,paymentsandotheractionsrequiredtobemadeortakentomaintainsuchitemofOpexaRegisteredIPinfullforceandeffecthavebeenmadebytheapplicabledeadline,exceptforanyfailuretoperformanyoftheforegoing,individuallyorcollectively,thatwouldnot(inanycaseorintheaggregate)materiallydetractfromthevalueoftheOpexaRegisteredIPsubjecttheretoormateriallyimpairtheoperationsofOpexa.

(i) Notrademark(whetherregisteredorunregistered)ortradenameowned,used,orappliedforbyOpexaconflictsorinterfereswithanytrademark(whetherregisteredorunregistered)ortradenameowned,used,orappliedforbyanyotherPerson.Noneofthegoodwillassociatedwithorinherentinanytrademark(whetherregisteredorunregistered)inwhichOpexahasorpurportstohaveanownershipinteresthasbeenimpairedasdeterminedbyOpexainaccordancewithGAAP.

(j) (i)OpexaisnotboundbyanyContracttoindemnify,defend,holdharmless,orreimburseanyotherPersonwithrespecttoanyIntellectualPropertyinfringement,misappropriation,orsimilarclaim,and(ii)neitherOpexanoranyofitsSubsidiarieshaseverassumed,oragreedtodischargeorotherwisetakeresponsibilityfor,anyexistingorpotentialliabilityofanotherPersonforinfringement,misappropriation,orviolationofanyIntellectualPropertyright,whichassumption,agreementorresponsibilityremainsinforceasofthedateofthisAgreement.

3.10 Material Contracts .

(a) Section3.10oftheOpexaDisclosureScheduleliststhefollowingOpexaContracts,effectiveasofthedateofthisAgreement(each,a“OpexaMaterialContract”andcollectively,the“OpexaMaterialContracts”):

(i) eachOpexaContractrelatingtoanymaterialbonus,deferredcompensation,severance,incentivecompensation,pension,profit-sharingorretirementplans,oranyotheremployeebenefitplansorarrangements;

(ii) eachOpexaContractrelatingtotheemploymentof,ortheperformanceofemployment-relatedservicesby,anyPerson,includinganyemployee,consultantorindependentcontractor,orentityprovidingemploymentrelated,consultingorindependentcontractorservices,notterminablebyOpexaonninety(90)calendardays’orlessnoticewithoutliability,excepttotheextentgeneralprinciplesofwrongfulterminationlawmaylimitOpexa’soritssuccessor’sabilitytoterminateemployeesatwill;

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(iii) eachOpexaContractrelatingtoanyagreementorplan,includinganystockoptionplan,stockappreciationrightplanorstockpurchaseplan,anyofthebenefitsofwhichwillbeincreased,orthevestingofbenefitsofwhichwillbeaccelerated,bytheoccurrenceofanyoftheContemplatedTransactions(eitheraloneorinconjunctionwithanyotherevent,suchasterminationofemployment)orthevalueofanyofthebenefitsofwhichwillbecalculatedonthebasisofanyoftheContemplatedTransactions;

(iv) eachOpexaContractrelatingtoanyagreementofindemnificationorguarantynotenteredintointheOrdinaryCourseofBusiness;

(v) eachOpexaContractcontaining(A)anycovenantlimitingthefreedomofOpexaortheSurvivingCorporationtoengageinanylineofbusinessorcompetewithanyPerson,(B)anymost-favoredpricingarrangement,(C)anyexclusivityprovision,or(D)anynon-solicitationprovision;

(vi) eachOpexaContractrelatingtocapitalexpendituresandinvolvingobligationsafterthedateofthisAgreementinexcessof$25,000;

(vii) eachOpexaContractrelatingtothedispositionoracquisitionofmaterialassetsoranyownershipinterestinanyEntity;

(viii) eachOpexaContractrelatingtoanymortgages,indentures,loans,notesorcreditagreements,securityagreementsorotheragreementsorinstrumentsrelatingtotheborrowingofmoneyorextensionofcreditinexcessof$25,000orcreatinganymaterialEncumbranceswithrespecttoanyassetsofOpexaoranyloansordebtobligationswithofficersordirectorsofOpexa;

(ix) eachOpexaContractrelatingto:(A)anydistributionagreement(identifyinganythatcontainexclusivityprovisions);(B)anyagreementinvolvingprovisionofservicesorproductswithrespecttoanypre-clinicalorclinicaldevelopmentactivitiesofOpexa;(C)anydealer,distributor,jointmarketing,alliance,jointventure,cooperation,developmentorotheragreementcurrentlyinforceunderwhichOpexahascontinuingobligationstodevelopormarketanyproduct,technologyorservice,oranyagreementpursuanttowhichOpexahascontinuingobligationstodevelopanyIntellectualPropertythatwillnotbeowned,inwholeorinpart,byOpexa;or(D)anyContracttolicenseanythirdpartytomanufactureorproduceanyproduct,serviceortechnologyofOpexaoranyContracttosell,distributeorcommercializeanyproductsorserviceofOpexa,exceptagreementsintheOrdinaryCourseofBusiness;

(x) eachOpexaContractwithanyPerson,includinganyfinancialadvisor,broker,finder,investmentbankerorotherPerson,providingadvisoryservicestoOpexainconnectionwiththeContemplatedTransactions;

(xi) eachOpexaIPRightAgreement;

(xii) any“materialcontract”(assuchtermisdefinedinItem601(b)(10)ofRegulationS-KoftheSecuritiesAct),whetherornotfiledbyOpexawiththeSEC;

(xiii) eachOpexaLease;or

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(xiv) anyotherOpexaContractthatisnotterminableatwill(withnopenaltyorpayment)byOpexaand(i)whichinvolvespaymentorreceiptbyOpexaafterthedateofthisAgreementunderanysuchagreement,contractorcommitmentofmorethan$25,000intheaggregate,orobligationsafterthedateofthisAgreementinexcessof$25,000intheaggregate,or(ii)thatismaterialtothebusinessoroperationsofOpexa.

(b) OpexahasdeliveredormadeavailabletoAceraccurateandcompletecopiesofallOpexaMaterialContracts,includingallamendmentsthereto.TherearenoOpexaMaterialContractsthatarenotinwrittenform.Opexahasnot,nortoOpexa’sKnowledge,asofthedateofthisAgreementhasanyotherpartytoanOpexaMaterialContract(asdefinedbelow)breached,violatedordefaultedunder,orreceivednoticethatithasbreached,violatedordefaultedunder,anyofthetermsorconditionsofanyOpexaMaterialContractinsuchmanneraswouldpermitanyotherpartytocancelorterminateanysuchOpexaMaterialContract,orwouldpermitanyotherpartytoseekdamagesthatwouldresultinanOpexaMaterialAdverseEffect.AsofthedateofthisAgreement,eachOpexaMaterialContractisvalid,binding,enforceableandinfullforceandeffect,subjectto:(i)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtors;and(ii)rulesoflawgoverningspecificperformance,injunctivereliefandotherequitableremedies.

3.11 Undisclosed Liabilities .AsofthedateofthisAgreement,neitherOpexanoritsSubsidiarieshaveanyLiabilities,exceptfor:(a)LiabilitiesidentifiedassuchintheOpexaUnauditedInterimBalanceSheet;(b)normalandrecurringcurrentLiabilitiesthathavebeenincurredbyOpexasincethedateoftheOpexaUnauditedInterimBalanceSheetintheOrdinaryCourseofBusinessandthatarenotinexcessof$25,000intheaggregate;(c)LiabilitiesforperformanceintheOrdinaryCourseofBusinessofobligationsofOpexaunderOpexaContracts,includingthereasonablyexpectedperformanceofsuchOpexaContractsinaccordancewiththeirterms(whichwouldnotinclude,forexample,anyinstancesofbreachorindemnification);(d)LiabilitiesdescribedinSection3.11oftheOpexaDisclosureSchedule;and(e)LiabilitiesincurredinconnectionwiththeContemplatedTransactions.

3.12 Compliance; Permits; Restrictions .

(a) Opexais,andsinceJanuary1,2011,eachofOpexaanditsSubsidiarieshasbeeninmaterialcompliancewithallapplicableLegalRequirements.Noinvestigation,claim,suit,proceeding,auditorotheractionbyanyGovernmentalBodyorauthorityispendingor,totheKnowledgeofOpexa,threatenedagainstOpexa.ThereisnoContract,judgment,injunction,orderordecreebindinguponOpexawhich(i)hasorwouldreasonablybeexpectedtohavetheeffectofprohibitingormateriallyimpairinganybusinesspracticeofOpexa,anyacquisitionofmaterialpropertybyOpexaortheconductofbusinessbyOpexaascurrentlyconducted,(ii)wouldreasonablybeexpectedtohaveanadverseeffectonOpexa’sabilitytocomplywithorperformanycovenantorobligationunderthisAgreementor(iii)wouldreasonablybeexpectedtohavetheeffectofpreventing,delaying,makingillegalorotherwiseinterferingwiththeMergeroranyoftheContemplatedTransactions.

(b) OpexaholdsallGovernmentalAuthorizationsthatarematerialtotheoperationofitsbusiness(collectively,the“OpexaPermits”)ascurrentlyconducted.Section3.12(b)oftheOpexaDisclosureScheduleidentifieseachOpexaPermit.Asofthedateofthis

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Agreement,OpexaisinmaterialcompliancewiththetermsoftheOpexaPermits.Noaction,proceeding,revocationproceeding,amendmentprocedure,writ,injunctionorclaimispendingor,totheKnowledgeofOpexa,threatened,whichseekstorevoke,limit,suspend,ormateriallymodifyanyOpexaPermit.TherightsandbenefitsofeachmaterialOpexaPermitwillbeavailabletotheSurvivingCorporationimmediatelyaftertheEffectiveTimeontermssubstantiallyidenticaltothoseenjoyedbyOpexaasofthedateofthisAgreementandimmediatelypriortotheEffectiveTime.

(c) Therearenoproceedingspendingor,totheKnowledgeofOpexa,threatenedwithrespecttoanallegedviolationbyOpexaoftheFDCA,FDAregulationsadoptedthereunder,theControlledSubstancesActoranyothersimilarLegalRequirementspromulgatedbytheFDAorotherDrugRegulatoryAgency.

(d) OpexaholdsallrequiredGovernmentalAuthorizationsissuablebyanyGovernmentalBodynecessaryfortheconductofitsbusinessascurrentlyconducted(the“OpexaRegulatoryPermits”)andnosuchOpexaRegulatoryPermithasbeen(i)revoked,withdrawn,suspended,canceledorterminatedor(ii)modifiedinanymateriallyadversemanner.OpexahasnotreceivedanywrittennoticeorotherwrittencommunicationfromanyGovernmentalBodyregardinganyrevocation,withdrawal,suspension,cancelation,terminationormaterialmodificationofanyOpexaRegulatoryPermit.OpexahasmadeavailabletoAcerallinformationinitspossessionorcontrolrelatingtothefollowing(totheextentthereareany):(A)adverseeventreports;clinicalstudyreportsandmaterialstudydata;andinspectionreports,noticesofadversefindings,warningletters,filingsandlettersandotherwrittencorrespondencetoandfromanyGovernmentalBody;andmeetingminuteswithanyGovernmentalBody;and(B)similarreports,materialstudydata,notices,letters,filings,correspondenceandmeetingminuteswithanyotherGovernmentalBody.

(e) Allclinical,pre-clinicalandotherstudiesandtestsconductedbyoronbehalfof,orsponsoredby,OpexaorinwhichOpexaoritsproductsorserviceshaveparticipatedwereconductedinallmaterialrespectsinaccordancewithstandardmedicalandscientificresearchproceduresandincompliancewithapplicableLegalRequirements.

(f) TotheKnowledgeofOpexa,nomaterialdebarmentorexclusionaryclaims,actions,proceedingsorinvestigationsinrespectoftheirbusinessorproductsarependingorthreatenedagainstOpexaoritsofficers,employeesoragents.

3.13 Tax Matters.

(a) EachofOpexaanditsSubsidiarieshastimelyfiledallfederalincomeTaxReturnsandothermaterialTaxReturnsthattheywererequiredtofileunderapplicableLegalRequirements.AllsuchTaxReturnswerecorrectandcompleteinallmaterialrespectsandhavebeenpreparedinmaterialcompliancewithallapplicableLegalRequirements.ExceptassetforthinSection3.13(a)oftheOpexaDisclosureSchedule,OpexaisnotcurrentlythebeneficiaryofanyextensionoftimewithinwhichtofileanyTaxReturn.NoclaimhaseverbeenmadebyanauthorityinajurisdictionwhereOpexaoritsSubsidiariesdonotfileTaxReturnsthatsuchcompanyissubjecttotaxationbythatjurisdiction.

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(b) AllmaterialTaxesdueandowingbyOpexaoranyofitsSubsidiariesonorbeforethedatehereof(whetherornotshownonanyTaxReturn)havebeenpaid.TheunpaidTaxesofOpexaanditsSubsidiarieshavebeenreservedforontheOpexaUnauditedInterimBalanceSheetinaccordancewithGAAP.SincethedateoftheOpexaUnauditedInterimBalanceSheet,OpexahasnotincurredanyLiabilityforTaxesoutsidetheOrdinaryCourseofBusinessorotherwiseinconsistentwithpastcustomandpractice.

(c) OpexahaswithheldandpaidallTaxesrequiredtohavebeenwithheldandpaidinconnectionwithanyamountspaidorowingtoanyemployee,independentcontractor,creditor,shareholderorotherthirdparty.

(d) TherearenoEncumbrancesforTaxes(otherthanTaxesnotyetdueandpayableorTaxesthatarebeingcontestedingoodfaithandforwhichadequatereserveshavebeenmadeonOpexa’sUnauditedInterimBalanceSheet)uponanyoftheassetsofOpexa.

(e) NomaterialdeficienciesforTaxeswithrespecttoOpexahavebeenclaimed,proposedorassessedbyanyGovernmentalBodyinwriting.Therearenopending(or,basedonwrittennotice,threatened)audits,assessmentsorotheractionsfororrelatingtoanyliabilityinrespectofTaxesofOpexa.NoissuesrelatingtoTaxesofOpexawereraisedbytherelevantTaxauthorityinanycompletedauditorexaminationthatwouldreasonablybeexpectedtoresultinamaterialamountofTaxesinalatertaxableperiod.OpexahasdeliveredormadeavailabletoAcercompleteandaccuratecopiesofallfederalincomeTaxandallothermaterialTaxReturnsofOpexa(andthepredecessorsofeach)foralltaxableyearsremainingopenundertheapplicablestatuteoflimitations,andcompleteandaccuratecopiesofallexaminationreportsandstatementsofdeficienciesassessedagainstoragreedtobyOpexawithrespecttofederalincomeTaxandallothermaterialTaxes.OpexahasnotwaivedanystatuteoflimitationsinrespectofTaxesoragreedtoanyextensionoftimewithrespecttoaTaxassessmentordeficiency,norhasanyrequestbeenmadeinwritingforanysuchextensionorwaiver.

(f) AllmaterialelectionswithrespecttoTaxesaffectingOpexaasofthedatehereofaresetforthonSection3.13(f)oftheOpexaDisclosureSchedule.Opexahasnot(i)consentedatanytimeunderformerSection341(f)(1)oftheCodetohavetheprovisionsofformerSection341(f)(2)oftheCodeapplytoanydispositionoftheassetsofOpexa;(ii)agreed,orisrequired,tomakeanyadjustmentunderSection481(a)oftheCodebyreasonofachangeinaccountingmethodorotherwise;(iii)madeanelection,orisrequired,totreatanyofitsassetsasownedbyanotherPersonforTaxpurposesorasatax-exemptbondfinancedpropertyortax-exemptusepropertywithinthemeaningofSection168oftheCode;(iv)acquiredorownsanyassetsthatdirectlyorindirectlysecureanydebttheinterestonwhichistaxexemptunderSection103(a)oftheCode;(v)madeorwillmakeaconsentdividendelectionunderSection565oftheCode;(vi)electedatanytimetobetreatedasanScorporationwithinthemeaningofSections1361or1362oftheCode;or(vii)madeanyoftheforegoingelectionsorisrequiredtoapplyanyoftheforegoingrulesunderanycomparableprovisionofstate,localorforeignlaw.

(g) OpexahasnotbeenaUnitedStatesrealpropertyholdingcorporationwithinthemeaningofSection897(c)(2)oftheCodeduringtheapplicableperiodspecifiedinSection897(c)(1)(A)(ii)oftheCode.

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(h) OpexaisnotapartytoanyTaxallocation,Taxsharingorsimilaragreement(includingindemnityarrangements),otherthancommercialcontractsenteredintointheOrdinaryCourseofBusinesswithvendors,customersandlandlords.

(i) NeitherOpexanoranyofitsSubsidiarieshaseverbeenamemberofanaffiliatedgroupfilingaconsolidated,combinedorunitaryTaxReturn(otherthanagroupthecommonparentofwhichisOpexa)forfederal,state,localorforeignTaxpurposes.OpexahasnoLiabilityfortheTaxesofanyPerson(otherthanOpexa)underTreasuryRegulationsSection1.1502-6(oranysimilarprovisionofstate,local,orforeignlaw),asatransfereeorsuccessor,byContractorotherwise.

(j) OpexahasnotdistributedstockofanotherPerson,orhashaditsstockdistributedbyanotherPerson,inatransactionthatwaspurportedorintendedtobegovernedinwholeorinpartbySection355oftheCodeorSection361oftheCode.

(k) OpexaisnotapartnerforTaxpurposeswithrespecttoanyjointventure,partnership,or,totheKnowledgeofOpexa,otherarrangementorcontractwhichistreatedasapartnershipforTaxpurposes.

(l) Opexawillnotberequiredtoincludeanyitemofincomein,orexcludeanyitemofdeductionfrom,taxableincomeforanyperiod(oranyportionthereof)endingaftertheClosingDateasaresultofany(i)installmentsaleorotheropentransactiondispositionmadeonorpriortotheClosingDate,or(ii)agreementwithanyTaxauthority(includinganyclosingagreementdescribedinSection7121oftheCodeoranysimilarprovisionofstate,localorforeignlaw)madeorenteredintoonorpriortotheClosingDate.

(m) Opexahasnotenteredintoanytransactionidentifiedasa“listedtransaction”forpurposesofTreasuryRegulationsSections1.6011-4(b)(2)or301.6111-2(b)(2).

(n) Opexahasnottakenanyaction,norhasanyknowledgeofanyfactorcircumstance,thatwouldreasonablybeexpectedtopreventtheContemplatedTransactionsfromqualifyingasareorganizationwithinthemeaningofSection368(a)oftheCode.

3.14 Employee and Labor Matters; Benefit Plans.

(a) TheemploymentofeachoftheOpexaemployeesisterminablebyOpexaatwill(orotherwiseinaccordancewithgeneralprinciplesofwrongfulterminationlaw).OpexahasmadeavailabletoAceraccurateandcompletecopiesofallemployeemanualsandhandbooks,disclosurematerials,policystatementsandothermaterialsrelatingtotheemploymentofOpexaAssociatestotheextentcurrentlyeffectiveandmaterial.

(b) Opexaisnot,andneitherOpexaoranyofitsSubsidiarieshasbeen,apartyto,boundby,orhas,orhad,adutytobargainunder,anycollectivebargainingagreementorotherContractwithalabororganization,tradeorlaborunion,employees’associationorsimilarorganizationrepresentinganyofitsemployees,andtherearenolabororganizations,tradeorlaborunions,employees’associationsorsimilarorganizationsrepresenting,purportingtorepresentor,totheKnowledgeofOpexa,seekingtorepresentanyemployeesofOpexa.

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(c) Section3.14(c)oftheOpexaDisclosureSchedulelists,asofthedateofthisAgreement,allwrittenanddescribesallnon-writtenemployeebenefitplans(asdefinedinSection3(3)ofERISA)andallbonus,equity-based,retention,incentive,deferredcompensation,retirementorsupplementalretirement,profitsharing,severance,goldenparachute,disability,lifeoraccidentinsurance,paidtimeoff,vacation,cafeteria,dependentcare,medicalcare,employeeassistanceprogram,educationortuitionassistanceprograms,fringeoremployeebenefit,andallothercompensation,plans,programs,agreementsorarrangements,includingbutnotlimitedtoanyemployment,consulting,independentcontractor,severanceorexecutivecompensationagreementsorarrangements(otherthanregularsalaryorwages),writtenorotherwise,whicharecurrentlyineffectrelatingtoanypresentorformeremployee,independentcontractorordirectorofOpexaoranyOpexaAffiliate,orwhichismaintainedby,administeredorcontributedtoby,orrequiredtobecontributedtoby,Opexa,anyofOpexa’sSubsidiariesoranyOpexaAffiliate,orunderwhichOpexa,anyofOpexa’sSubsidiariesoranyOpexaAffiliatehasincurredormayincuranyliability(each,an“OpexaEmployeePlan”).

(d) WithrespecttoeachOpexaEmployeePlan,OpexahasmadeavailabletoAceratrueandcompletecopyof,totheextentapplicable,(i)suchOpexaEmployeePlan,(ii)thethreemostrecentannualreports(Form5500)asfiledwiththeInternalRevenueService,(iii)eachcurrentlyeffectivetrustagreementrelatedtosuchOpexaEmployeePlan,(iv)themostrecentsummaryplandescriptionforeachOpexaEmployeePlanforwhichsuchdescriptionisrequired,alongwithallsummariesofmaterialmodifications,amendments,resolutionsandallothermaterialplandocumentationrelatedtheretointhepossessionofOpexa,(v)themostrecentInternalRevenueServicedeterminationoropinionletteroranalogousrulingunderforeignlawissuedwithrespecttoanyOpexaEmployeePlan,(vi)allmaterialnotices,lettersorothercorrespondencetoorfromanyGovernmentalBodyoragencythereofwithinthelastthreeyears;(vii)allnon-discriminationtestsforthemostrecentthreeplanyears;(viii)allmaterialwrittenagreementsandContractscurrentlyineffect,including(withoutlimitation)administrativeserviceagreements,groupannuitycontracts,andgroupinsurancecontracts;(ix)allmaterialwrittenemployeecommunicationswithinthepastthreeyears,and(x)allregistrationstatementsandprospectusespreparedinconnectionwitheachOpexaEmployeePlan.

(e) EachOpexaEmployeePlanthatisintendedtobequalifiedunderSection401(a)oftheCodehasreceivedafavorabledeterminationormayrelyonafavorableopinionletterwithrespecttosuchqualifiedstatusfromtheInternalRevenueService.TotheKnowledgeofOpexa,nothinghasoccurredthatwouldreasonablybeexpectedtoadverselyaffectthequalifiedstatusofanysuchOpexaEmployeePlanortheexemptstatusofanyrelatedtrust.EachOpexaEmployeePlanhasbeenmaintainedincomplianceinallmaterialrespects,withitstermsand,bothastoformandoperations,withallapplicableLegalRequirements,includingtheCodeandERISA.ExceptassetforthinSection3.14(e)(i)oftheOpexaDisclosureSchedule,eachOpexaEmployeePlancanbeamended,terminatedorotherwisediscontinuedinaccordancewithitsterms,withoutmaterialLiabilitytoOpexa,theSurvivingCorporation,AceroranyoftheirAffiliates(otherthanordinaryadministrativeexpensestypicallyincurredinaterminationevent).ExceptassetforthinSection3.14(e)(ii)oftheOpexaDisclosureSchedule,neitherOpexanoranyOpexaAffiliatehasannounceditsintentiontomodifyoramendanyOpexaEmployeePlanoradoptanyarrangementorprogramwhich,onceestablished,wouldcomewithinthedefinitionofanOpexaEmployeePlan,andtotheKnowledgeofOpexa,eachassetheldundersuchOpexaEmployeePlanmaybeliquidatedorterminatedwithouttheimpositionofanymaterial

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redemptionfee,surrenderchargeorcomparableLiability.Opexa,eachofitsSubsidiariesandeachOpexaAffiliatehasperformedallobligationsrequiredtobeperformedbyitunder,isnotindefaultunderorinviolationof,andhasnoknowledgeofanydefaultorviolationbyanyotherpartyto,anyoftheOpexaEmployeePlans.NeitherOpexa,anyofitsSubsidiaries,noranyOpexaAffiliateissubjecttoanyLiabilityorpenaltyunderSections4976through4980oftheCodeorTitleIofERISAwithrespecttoanyoftheOpexaEmployeePlans.AllcontributionsrequiredtobemadebyOpexa,anyofitsSubsidiariesoranyOpexaAffiliatetoanyOpexaEmployeePlanhavebeenmadeonorbeforetheirduedates(andnofurthercontributionswillbedueorwillhaveaccruedthereunderasoftheClosingDate,otherthancontributionsaccruedintheordinarycourseofbusinessconsistentwithpastpractice).Nosuit,administrativeproceeding,actionorotherlitigationhasbeeninitiatedagainst,ortotheKnowledgeofOpexa,isthreatened,againstorwithrespecttoanyOpexaEmployeePlan,includinganyauditorinquirybytheIRS,UnitedStatesDepartmentofLabororotherGovernmentalBody.

(f) NeitherOpexa,noranyofitsSubsidiariesoranyOpexaAffiliatehasengagedinanytransactioninviolationofSections404or406ofERISAorany“prohibitedtransaction,”asdefinedinSection4975(c)(1)oftheCode,forwhichnoexemptionexistsunderSection408ofERISAorSection4975(c)(2)or(d)oftheCode,orhasotherwiseviolatedtheprovisionsofPart4ofTitleI,SubtitleBofERISA.NeitherOpexa,noranyofitsSubsidiariesoranyOpexaAffiliatehasknowinglyparticipatedinaviolationofPart4ofTitleI,SubtitleBofERISAbyanyplanfiduciaryofanyOpexaEmployeePlansubjecttoERISAandneitherOpexa,noranyofitsSubsidiariesoranyOpexaAffiliatehasbeenassessedanycivilpenaltyunderSection502(l)ofERISA.

(g) NoOpexaEmployeePlanissubjecttoTitleIVorSection302ofERISAorSection412oftheCode,andneitherOpexa,noranyofitsSubsidiariesoranyOpexaAffiliatehasevermaintained,contributedtoorpartiallyorcompletelywithdrawnfrom,orincurredanyobligationorliabilitywithrespectto,anysuchplan.NoOpexaEmployeePlanisaMultiemployerPlan,andneitherOpexa,noranyofitsSubsidiariesoranyOpexaAffiliatehasevercontributedtoorhadanobligationtocontribute,orincurredanyliabilityinrespectofacontribution,toanyMultiemployerPlan.NoOpexaEmployeePlanisaMultipleEmployerPlan.

(h) ExceptassetforthonSection3.14(h)oftheOpexaDisclosureSchedule,noOpexaEmployeePlanprovidesformedicalordeathbenefitsbeyondterminationofserviceorretirement,otherthan(i)pursuanttoCOBRAorananalogousstatelawrequirementor(ii)deathorretirementbenefitsunderanOpexaEmployeePlanqualifiedunderSection401(a)oftheCode.NeitherOpexanoranyOpexaAffiliatesponsorsormaintainsanyself-fundedemployeebenefitplan.NoOpexaEmployeePlanissubjecttoanyLegalRequirementofanyforeignjurisdictionoutsideoftheUnitedStates.

(i) TotheKnowledgeofOpexa,nopaymentpursuanttoanyOpexaEmployeePlanorotherarrangementtoany“serviceprovider”(assuchtermisdefinedinSection409AoftheCodeandtheUnitedStatesTreasuryRegulationsandIRSguidancethereunder)fromOpexaoranyofitsSubsidiaries,includingthegrant,vestingorexerciseofanystockoption,wouldsubjectanyPersontotaxpursuanttoSection409A(1)oftheCode,whetherpursuanttotheContemplatedTransactionsorotherwise.

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(j) WithrespecttoOpexaOptionsgrantedpursuanttothe2010Plan,(i)eachOpexaOptionintendedtoqualifyasan“incentivestockoption”underSection422oftheCodesoqualifies,(ii)eachgrantofanOpexaOptionwasdulyauthorizednolaterthanthedateonwhichthegrantofsuchOpexaOptionwasbyitstermstobeeffectivebyallnecessarycorporateaction,including,asapplicable,approvalbytheOpexaBoardofDirectors(oradulyconstitutedandauthorizedcommitteethereof)andanyrequiredshareholderapprovalbythenecessarynumberofvotesorwrittenconsents,andtheawardagreementgoverningsuchgrant(ifany)wasdulyexecutedanddeliveredbyeachpartythereto,(iii)eachOpexaOptiongrantwasmadeinaccordancewiththetermsofthe2010Plan,theExchangeActandallotherapplicableLegalRequirements,includingtherulesofNASDAQandanyotherexchangeonwhichOpexasecuritiesaretraded,(iv)thepershareexercisepriceofeachOpexaOptionwasnotlessthanthefairmarketvalueofashareofOpexaCommonStockontheapplicableGrantDateand(v)eachsuchOpexaOptiongrantwasproperlyaccountedforinaccordancewithGAAPinthefinancialstatements(includingtherelatednotes)ofOpexaanddisclosedinOpexafilingswiththeSecuritiesandExchangeCommissioninaccordancewiththeExchangeActandallotherapplicableLegalRequirements.Opexahasnotknowinglygranted,andthereisnoandhasbeennopolicyorpracticeofOpexaofgranting,OpexaOptionspriorto,orotherwisecoordinatingthegrantofOpexaOptionswith,thereleaseorotherpublicannouncementofmaterialinformationregardingOpexaoritsresultsofoperationsorprospects.

(k) NoOpexaOptions,stockappreciationrightsorotherequity-basedawardsissuedorgrantedbyOpexaaresubjecttotherequirementsofCodeSection409A.Each“nonqualifieddeferredcompensationplan”(assuchtermisdefinedunderSection409A(d)(1)oftheCodeandtheguidancethereunder)maintainedbyorunderwhichOpexaoranyofitsSubsidiariesmakes,isobligatedtomakeorpromisestomake,payments(each,a“Opexa409APlan”)compliesinallmaterialrespects,inbothformandoperation,withtherequirementsofCodeSection409Aandtheguidancethereunder.NopaymenttobemadeunderanyOpexa409APlanis,ortotheKnowledgeofOpexawillbe,subjecttothepenaltiesofCodeSection409A(a)(1).

(l) Opexaisincompliancewithallofitsbonus,commissionandothercompensationplansandhaspaidanyandallamountsrequiredtobepaidundersuchplans,includinganyandallbonusesandcommissions(orprorataportionthereof)thatmayhaveaccruedorbeenearnedthroughthecalendarquarterprecedingtheEffectiveTime,andisnotliableforanypayments,taxesorpenaltiesforfailuretocomplywithanyofthetermsorconditionsofsuchplansorthelawsgoverningsuchplans.

(m) EachofOpexaanditsSubsidiarieshascompliedinallmaterialrespectswithallstateandfederallawsapplicabletoemployees,includingbutnotlimitedtoCOBRA,FMLA,CFRA,HIPAA,theWomen’sHealthandCancerRightsActof1998,theNewborn’sandMothers’HealthProtectionActof1996,andanysimilarprovisionsofstatelawapplicabletoitsemployees.TotheextentrequiredunderHIPAAandtheregulationsissuedthereunder,OpexaandeachofitsSubsidiarieshas,priortotheClosingDate,performedallobligationsunderthemedicalprivacyrulesofHIPAA(45C.F.R.Parts160and164),theelectronicdatainterchangerequirementsofHIPAA(45C.F.R.Parts160and162),andthesecurityrequirementsofHIPAA(45C.F.R.Part142).NeitherOpexanoranyofitsSubsidiarieshasanymaterialunsatisfiedobligationstoanyofitsemployeesorqualifiedbeneficiariespursuanttoCOBRA,HIPAAorany

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statelawgoverninghealthcarecoverageorextension.OpexaandeachOpexaAffiliateisincomplianceinallmaterialrespectswithallapplicablerequirementsoftheACA,includingallrequirementsrelatingtoeligibilitywaitingperiodsandtheofferoforprovisionofminimumessentialcoveragethatiscompliantwithSection36B(c)(2)(C)oftheCodeandtheregulationsissuedthereundertofull-timeemployeesasdefinedinSection4980H(c)(4)oftheCodeandtheregulationsissuedthereunder.NoexcisetaxorpenaltyundertheACA,includingSections4980Dand4980HoftheCode,isoutstanding,hasaccrued,orhasarisenwithrespecttoanyperiodpriortotheClosing,withrespecttoanyOpexaEmployeePlan.NeitherOpexanoranyOpexaAffiliatehasanyunsatisfiedobligationstoanyemployeesorqualifiedbeneficiariespursuanttotheACA,oranystateorlocalLegalRequirementgoverninghealthcarecoverageorbenefitsthatwouldreasonablybeexpectedtoresultinanymaterialliabilitytoOpexa.EachofOpexaanditsOpexaAffiliateshasmaintainedallrecordsnecessarytodemonstrateitscompliancewiththeACA.

(n) OpexaanditsSubsidiariesareinmaterialcompliancewithallapplicableforeign,federal,stateandlocallaws,rules,regulations,orders,rulings,judgments,decreesorarbitrationawardsrespectingemployment,employmentpractices,termsandconditionsofemployment,workerclassification,taxwithholding,prohibiteddiscrimination,equalemployment,fairemploymentpractices,mealandrestperiods,immigrationstatus,employeesafetyandhealth,wages(includingovertimewages),compensation,hoursofwork,laborrelations,leaveofabsencerequirements,occupationalhealthandsafety,privacy,harassment,retaliation,immigrationandwrongfuldischargeandineachcase,withrespecttoemployees:(i)haswithheldandreportedallamountsrequiredbylaworbyagreementtobewithheldandreportedwithrespecttowages,salariesandotherpaymentstoemployees,(ii)exceptassetforthinSection3.14(n)oftheOpexaDisclosureSchedule,isnotliableforanyarrearsofwages,severancepayoranyTaxesoranypenaltyofanymaterialamountforfailuretocomplywithanyoftheforegoing,and(iii)isnotliableforanypaymenttoanytrustorotherfundgovernedbyormaintainedbyoronbehalfofanyGovernmentalBody,withrespecttounemploymentcompensationbenefits,socialsecurityorotherbenefitsorobligationsforemployees(otherthanroutinepaymentstobemadeinthenormalcourseofbusinessandconsistentwithpastpractice).Therearenoactions,suits,claimsoradministrativematterspending,ortotheKnowledgeofOpexa,threatenedorreasonablyanticipatedagainstOpexarelatingtoanyemployee,employmentagreement,independentcontractor,independentcontractoragreementorOpexaEmployeePlan.Therearenopendingor,totheKnowledgeofOpexa,threatenedorreasonablyanticipatedclaimsoractionsagainstOpexaoranytrusteeofOpexaunderanyworker’scompensationpolicyorlong-termdisabilitypolicy.Opexaisnotapartytoaconciliationagreement,consentdecreeorotheragreementororderwithanyfederal,state,orlocalagencyorGovernmentalBodywithrespecttoemploymentpractices.

(o) NocurrentorformerindependentcontractorofOpexaoranyofitsSubsidiarieswouldreasonablybedeemedtobeamisclassifiedemployee.ExceptassetforthonSection3.14(o)oftheOpexaDisclosureSchedule,noindependentcontractoriseligibletoparticipateinanyOpexaEmployeePlan.NeitherOpexanoranyofitsSubsidiarieshasmaterialliabilitywithrespecttoanymisclassificationof:(A)anyPersonasanindependentcontractorratherthanasanemployee,(B)anyemployeeleasedfromanotheremployer,or(C)anyemployeecurrentlyorformerlyclassifiedasexemptfromovertimewages.NeitherOpexanoranyofitsSubsidiarieshastakenanyactionwhichwouldconstitutea“plantclosing”or“mass

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layoff”withinthemeaningoftheWARNActorsimilarstateorlocallaw,issuedanynotificationofaplantclosingormasslayoffrequiredbytheWARNActorsimilarstateorlocallaw,orincurredanyliabilityorobligationunderWARNoranysimilarstateorlocallawthatremainsunsatisfied.NoterminationsofemployeesofOpexapriortotheClosingwouldtriggeranynoticeorotherobligationsundertheWARNActorsimilarstateorlocallaw.

(p) Therehasneverbeen,norhastherebeenanythreatof,anystrike,slowdown,workstoppage,lockout,jobaction,unionorganizingactivity,oranysimilaractivityordispute,affectingOpexaoranyofitsSubsidiaries.Noeventhasoccurred,andnoconditionorcircumstanceexists,thatmightdirectlyorindirectlybelikelytogiverisetoorprovideabasisforthecommencementofanysuchstrike,slowdown,workstoppage,lockout,jobaction,unionorganizingactivity,questionconcerningrepresentationoranysimilaractivityordispute.

(q) Opexaisnot,andneitherOpexanoranyofitsSubsidiaries,hasbeen,engagedinanyunfairlaborpracticewithinthemeaningoftheNationalLaborRelationsAct.ThereisnoLegalProceeding,claim,labordisputeorgrievancependingor,totheKnowledgeofOpexa,threatenedorreasonablyanticipatedrelatingtoanyemploymentcontract,privacyright,labordispute,wagesandhours,leaveofabsence,plantclosingnotification,workers’compensationpolicy,long-termdisabilitypolicy,harassment,retaliation,immigration,employmentstatuteorregulation,safetyordiscriminationmatterinvolvinganyOpexaAssociate,includingchargesofunfairlaborpracticesordiscriminationcomplaintsthatindividuallyorintheaggregatewouldresultinmaterialLiabilitytoOpexa.

(r) ThereisnoContractorarrangementtowhichOpexaoranyOpexaAffiliateisapartyorbywhichitisboundtocompensateanyofitscurrentorformeremployees,independentcontractorsordirectorsforadditionalincomeorexcisetaxespaidpursuanttoSections409Aor4999oftheCode.

(s) NeitherOpexanoranyOpexaAffiliateisapartytoanyContractthathasresultedorwouldreasonablybeexpectedtoresult,separatelyorintheaggregate,inthepaymentof(i)any“excessparachutepayment”withinthemeaningofSection280GoftheCodeand(ii)anyamountthedeductionforwhichwouldbedisallowedunderSection162(m)oftheCode.

(t) ExceptassetforthinSection3.14(t)oftheOpexaDisclosureSchedule,noneoftheexecutionanddeliveryofthisAgreement,ortheconsummationoftheContemplatedTransactionsoranyterminationofemploymentorserviceoranyothereventinconnectiontherewithorsubsequenttheretowill,individuallyortogetherorwiththeoccurrenceofsomeotherevent,(i)resultinanypayment(includingseverance,unemploymentcompensation,goldenparachute,bonusorotherwise)becomingduetoanyemployee,independentcontractorordirectorofOpexa,(ii)materiallyincreaseorotherwiseenhanceanybenefitsotherwisepayablebyOpexa,(iii)resultintheaccelerationofthetimeofpaymentorvestingofanysuchbenefits,exceptasrequiredunderSection411(d)(3)oftheCode,(iv)increasetheamountofcompensationduetoanyPersonbyOpexaor(v)resultintheforgivenessinwholeorinpartofanyoutstandingloansmadebyOpexatoanyPerson.

3.15 Environmental Matters .OpexaisinmaterialcompliancewithallapplicableEnvironmentalLaws,whichcomplianceincludesthepossessionbyOpexaofallpermitsand

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otherGovernmentalAuthorizationsrequiredunderapplicableEnvironmentalLawsandcompliancewiththetermsandconditionsthereofotherthananyfailuretobeincomplianceorpossessanysuchpermitsandauthorizedthatisnotanOpexaMaterialAdverseEffect.NeitherOpexanoranyofitsSubsidiarieshasreceivedsinceJanuary1,2011anywrittennoticeorothercommunication(inwritingorotherwise),whetherfromaGovernmentalBody,citizensgroup,employeeorotherwise,thatallegesthatOpexaisnotincompliancewithanyEnvironmentalLaw,and,totheKnowledgeofOpexa,therearenocircumstancesthatmaypreventorinterferewithOpexa’scompliancewithanyEnvironmentalLawinthefuture.TotheKnowledgeofOpexa:(i)nocurrentorpriorownerofanypropertyleasedorcontrolledbyOpexaoranyofitsSubsidiarieshasreceivedsinceJanuary1,2011,anywrittennoticeorothercommunicationrelatingtopropertyownedorleasedatanytimebyOpexa,whetherfromaGovernmentalBody,citizensgroup,employeeorotherwise,thatallegesthatsuchcurrentorpriorownerorOpexaoranyofitsSubsidiariesisnotincompliancewithorhasviolatedanyEnvironmentalLawrelatingtosuchpropertyand(ii)neitherOpexanoranyofitsSubsidiarieshasanymaterialliabilityunderanyEnvironmentalLaw.

3.16 Insurance.

(a) OpexamadeavailabletoAceraccurateandcompletecopiesofallmaterialinsurancepoliciesandallmaterialself-insuranceprogramsandarrangementsrelatingtothebusiness,assets,liabilitiesandoperationsofOpexa,asofthedateofthisAgreement.EachofsuchinsurancepoliciesisinfullforceandeffectandOpexaisincompliancewiththetermsthereof.AsofthedateofthisAgreement,otherthancustomaryendofpolicynotificationsfrominsurancecarriers,sinceJanuary1,2011,Opexahasnotreceivedanynoticeorothercommunicationregardinganyactualorpossible:(a)cancelationorinvalidationofanyinsurancepolicy;(b)refusalordenialofanycoverage,reservationofrightsorrejectionofanymaterialclaimunderanyinsurancepolicy;or(c)materialadjustmentintheamountofthepremiumspayablewithrespecttoanyinsurancepolicy.Thereisnopendingworkers’compensationorotherclaimunderorbaseduponanyinsurancepolicyofOpexa.Allinformationprovidedtoinsurancecarriers(inapplicationsandotherwise)onbehalfofOpexaisaccurateandcomplete.Opexahasprovidedtimelywrittennoticetotheappropriateinsurancecarrier(s)ofeachLegalProceedingpendingorthreatenedinwritingagainstOpexa,andnosuchcarrierhasissuedadenialofcoverageorareservationofrightswithrespecttoanysuchLegalProceeding,orinformedOpexaofitsintenttodoso.

(b) OpexahasdeliveredtoAceraccurateandcompletecopiesoftheexistingpolicies(primaryandexcess)ofdirectors’andofficers’liabilityinsurancemaintainedbyOpexaandeachOpexaSubsidiaryasofthedateofthisAgreement(the“ExistingOpexaD&OPolicies”).Section3.16(b)oftheOpexaDisclosureScheduleaccuratelysetsforth,asofthedateofthisAgreement,themostrecentannualpremiumspaidbyOpexaandeachOpexaSubsidiarywithrespecttotheExistingOpexaD&OPolicies.AllpremiumsfortheExistingOpexaD&OPolicieshavebeenpaid.

3.17 Legal Proceedings; Orders.

(a) ThereisnopendingLegalProceeding,and,totheKnowledgeofOpexa,noPersonhasthreatenedinwritingtocommenceanyLegalProceeding:(i)thatinvolvesOpexa,

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ortotheKnowledgeofOpexa,anydirectororofficerofOpexa(inhisorhercapacityassuch)oranyofthematerialassetsownedorusedbyOpexa;or(ii)thatchallenges,orthatwouldreasonablybeexpectedtohavetheeffectofpreventing,delaying,makingillegalorotherwiseinterferingwith,theContemplatedTransactions.TotheKnowledgeofOpexa,noeventhasoccurred,andnoclaim,disputeorotherconditionorcircumstanceexists,thatwill,orthatwouldreasonablybeexpectedto,giverisetoorserveasabasisforthecommencementofanysuchLegalProceeding.

(b) Thereisnoorder,writ,injunction,judgmentordecreetowhichOpexaoranyofthematerialassetsownedorusedbyOpexa,issubject.TotheKnowledgeofOpexa,noofficerofOpexaissubjecttoanyorder,writ,injunction,judgmentordecreethatprohibitssuchofficerfromengaginginorcontinuinganyconduct,activityorpracticerelatingtothebusinessofOpexaortoanymaterialassetsownedorusedbyOpexa.

3.18 Inapplicability of Anti-Takeover Statutes .TheOpexaBoardofDirectorsandtheboardofdirectorsofMergerSubhavetakenandwilltakeallactionsnecessarytoensurethattherestrictionsapplicabletobusinesscombinationscontainedinSubchapterMofChapter21oftheTBOC,orSection203oftheDGCL,asapplicable,are,andwillbe,inapplicabletotheexecution,deliveryandperformanceofthisAgreementandtheOpexaShareholderSupportAgreementsandtotheconsummationofContemplatedTransactions.NootherstatetakeoverstatuteorsimilarLegalRequirementappliesorpurportstoapplytotheMerger,thisAgreement,theOpexaShareholderSupportAgreementsoranyoftheotherContemplatedTransactions,ineachcaseduetothefactthateitherOpexaorMergerSubisapartytosuchmatters.

3.19 No Financial Advisor .ExceptassetforthonSection3.19oftheOpexaDisclosureSchedule,nobroker,finderorinvestmentbankerisentitledtoanybrokeragefee,finder’sfee,opinionfee,successfee,transactionfeeorotherfeeorcommissioninconnectionwiththeContemplatedTransactionsbaseduponarrangementsmadebyoronbehalfofOpexaorMergerSub.

3.20 Disclosure .TheinformationsuppliedbyOpexaforinclusionintheProxyStatement/Prospectus/InformationStatementwillnot,asofthedateoftheProxyStatement/Prospectus/InformationStatementorasofthedatesuchinformationisfirstmailedtoOpexaShareholders,(i)containanyuntruestatementofanymaterialfactor(ii)omittostateanymaterialfactnecessaryinordertomakesuchinformation,inthelightofthecircumstancesunderwhichsuchinformationisprovided,notfalseormisleading.

3.21 Bank Accounts; Deposits .

(a) Section3.21(a)oftheOpexaDisclosureScheduleprovidesaccurateinformationwithrespecttoeachaccountmaintainedbyorforthebenefitofOpexaatanybankorotherfinancialinstitution,includingthenameofthebankorfinancialinstitution,theaccountnumber,thebalanceasofMay31,2017andthenamesofallindividualsauthorizedtodrawonormakewithdrawalsfromsuchaccounts.

(b) AllexistingaccountsreceivableofOpexa(includingthoseaccountsreceivablereflectedontheOpexaUnauditedInterimBalanceSheetthathavenotyetbeen

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collectedandthoseaccountsreceivablethathavearisensincethedateoftheOpexaUnauditedInterimBalanceSheetandhavenotyetbeencollected)(i)representvalidobligationsofcustomersofOpexaarisingfrombonafidetransactionsenteredintointheOrdinaryCourseofBusiness,and(ii)arecurrentandcollectibleinfullwhendue,withoutanycounterclaimorsetoff,netofapplicablereservesforbaddebtsontheOpexaUnauditedInterimBalanceSheet.AlldepositsofOpexa(includingthosesetforthontheOpexaUnauditedInterimBalanceSheet)whichareindividuallymorethan$10,000ormorethan$25,000intheaggregatearefullyrefundabletoOpexa.

3.22 Transactions with Affiliates .ExceptassetforthintheOpexaSECDocumentsfiledpriortothedateofthisAgreement,sincethedateofOpexa’slastproxystatementfiledwiththeSEC,noeventhasoccurredthatwouldberequiredtobereportedbyOpexapursuanttoItem404ofRegulationS-KpromulgatedbytheSEC.Section3.22oftheOpexaDisclosureScheduleidentifieseachPersonwhois(orwhomaybedeemedtobe)anAffiliateofOpexaasofthedateofthisAgreement.

3.23 Valid Issuance .TheOpexaCommonStocktobeissuedintheMergerwill,whenissuedinaccordancewiththeprovisionsofthisAgreementbevalidlyissued,fullypaidandnonassessable.

3.24 Code of Ethics .Opexahasadoptedacodeofethics,asdefinedbyItem406(b)ofRegulationS-KoftheSEC,forseniorfinancialofficers,applicabletoitsprincipalexecutiveofficer,principalfinancialofficer,controllerorprincipalaccountingofficer,orpersonsperformingsimilarfunctions.OpexahaspromptlydisclosedanychangeinorwaiverofOpexa’scodeofethicswithrespecttoanysuchpersons,asrequiredbySection406(b)oftheSarbanes-OxleyAct.TotheKnowledgeofOpexa,therehavebeennoviolationsofprovisionsofOpexa’scodeofethicsbyanysuchpersons.

3.25 Shell Company Status .Opexaisnot,andhasnotbeenforatleastthepastten(10)years,anissueridentifiedinRule144(i)(1)(i)oftheSecuritiesActorashellcompanyasdefinedinRule12b-2oftheExchangeAct.

3.26 Anti-Corruption Matters .SinceJanuary1,2011,noneofOpexa,oranyofitsdirectors,officersor,totheKnowledgeofOpexa,employeesoragentshas:(i)usedanyfundsforunlawfulcontributions,gifts,entertainment,orotherunlawfulpaymentsrelatingtoanactbyanyGovernmentalBody;(ii)madeanyunlawfulpaymenttoanyforeignordomesticgovernmentofficialoremployeeortoanyforeignordomesticpoliticalpartyorcampaignorviolatedanyprovisionoftheU.S.ForeignCorruptPracticesActof1977,asamended;or(iii)madeanyotherunlawfulpaymentunderanyapplicableLegalRequirementrelatingtoanti-corruption,bribery,orsimilarmatters.SinceJanuary1,2011,OpexahasnotdisclosedtoanyGovernmentalBodythatitviolatedormayhaveviolatedanyLegalRequirementrelatingtoanti-corruption,bribery,orsimilarmatters.TotheKnowledgeofOpexa,noGovernmentalBodyisinvestigating,examining,orreviewingOpexa’scompliancewithanyapplicableprovisionsofanyLegalRequirementrelatingtoanti-corruption,bribery,orsimilarmatters.

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3.27 Exclusivity of Representations; Reliance .

(a) ExceptasexpresslysetforthinthisArticle3,neitherOpexa,MergerSub,noranyPersononbehalfofOpexaorMergerSubhasmade,norareanyofthemmaking,anyrepresentationorwarranty,writtenororal,expressorimplied,atlaworinequity,includingwithrespecttomerchantabilityorfitnessforanyparticularpurpose,inrespectofOpexaoritsbusinessinconnectionwiththetransactionscontemplatedhereby,includinganyrepresentationsorwarrantiesabouttheaccuracyorcompletenessofanyinformationordocumentspreviouslyprovided(includingwithrespecttoanyfinancialorotherprojectionstherein),andanyothersuchrepresentationsandwarrantiesareherebyexpresslydisclaimed.

(b) OpexaandMergerSubacknowledgeandagreethat,exceptfortherepresentationsandwarrantiesofAcersetforthinArticle2,noneofOpexa,MergerSuboranyoftheirrespectiveRepresentativesisrelyingonanyotherrepresentationorwarrantyofAceroranyotherPersonmadeoutsideofArticle2ofthisAgreement,includingregardingtheaccuracyorcompletenessofanysuchotherrepresentationsorwarrantiesortheomissionofanymaterialinformation,whetherexpressorimplied,ineachcasewithrespecttotheContemplatedTransactions.

ARTICLE 4

CERTAIN COVENANTS OF THE PARTIES

4.1 Access and Investigation .SubjecttothetermsoftheConfidentialityAgreementwhichthePartiesagreewillcontinueinfullforcefollowingthedateofthisAgreement,duringtheperiodcommencingonthedateofthisAgreementandcontinuinguntiltheearlieroftheterminationofthisAgreementinaccordancewiththetermsheretoandtheEffectiveTime(the“Pre-ClosingPeriod”),uponreasonablenoticeeachPartyshall,andshallusecommerciallyreasonableeffortstocausesuchParty’sRepresentativesto:

(a) providetheotherPartyandsuchotherParty’sRepresentativeswithreasonableaccessduringnormalbusinesshourstosuchParty’sRepresentatives,personnelandassetsandtoallexistingbooks,records,TaxReturns,workpapersandotherdocumentsandinformationrelatingtosuchPartyanditsSubsidiaries;

(b) providetheotherPartyandsuchotherParty’sRepresentativeswithsuchcopiesoftheexistingbooks,records,TaxReturns,workpapers,productdata,andotherdocumentsandinformationrelatingtosuchPartyanditsSubsidiaries,andwithsuchadditionalfinancial,operatingandotherdataandinformationregardingsuchPartyanditsSubsidiariesastheotherPartymayreasonablyrequest;and

(c) permittheotherParty’sofficersandotheremployeestomeet,uponreasonablenoticeandduringnormalbusinesshours,withthechieffinancialofficerandotherofficersandmanagersofsuchPartyresponsibleforsuchParty’sfinancialstatementsandtheinternalcontrolsofsuchPartytodiscusssuchmattersastheotherPartymaydeemnecessaryorappropriateinordertoenabletheotherPartytosatisfyitsobligationsundertheSarbanes-OxleyActandtherulesandregulationsrelatingthereto.Withoutlimitingthegeneralityofanyofthe

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foregoing,duringthePre-ClosingPeriod,eachParty,asapplicable,shallpromptlymakeavailabletotheotherPartycopiesof:

(i) theunauditedmonthlyconsolidatedbalancesheetsofsuchPartyasoftheendofeachcalendarmonthandtherelatedunauditedmonthlyconsolidatedstatementsofoperations,statementsofshareholders/stockholders’equityandstatementsofcashflowsforsuchcalendarmonth,whichshallbedeliveredwithin30calendardaysaftertheendofsuchcalendarmonth,orsuchlongerperiodsasthePartiesmayagreetoinwriting;

(ii) anywrittenmaterialsorcommunicationssentbyoronbehalfofaPartytoitsshareholders/stockholders;

(iii) anymaterialnotice,documentorothercommunicationsentbyoronbehalfofaPartytoanypartytoanyOpexaMaterialContractorAcerMaterialContract,asapplicable,orsenttoaPartybyanypartytoanyOpexaMaterialContractorAcerMaterialContract,asapplicable(otherthananycommunicationthatrelatessolelytoroutinecommercialtransactionsbetweensuchPartyandtheotherpartytoanysuchOpexaMaterialContractorAcerMaterialContract,asapplicable,andthatisofthetypesentintheOrdinaryCourseofBusinessandconsistentwithpastpractices);

(iv) anynotice,reportorotherdocumentfiledwithorotherwisefurnished,submittedorsenttoanyGovernmentalBodyonbehalfofaPartyinconnectionwiththeMergeroranyoftheContemplatedTransactions;

(v) anynon-privilegednotice,documentorothercommunicationsentbyoronbehalfof,orsentto,aPartyrelatingtoanypendingorthreatenedLegalProceedinginvolvingoraffectingsuchParty;and

(vi) anymaterialnotice,reportorotherdocumentreceivedbyaPartyfromanyGovernmentalBody.

(d) Notwithstandingtheforegoing,(i)anyPartymayrestricttheforegoingaccesstotheextentthatanyLegalRequirementapplicabletosuchPartyrequiressuchPartytorestrictorprohibitaccesstoanyofsuchParty’spropertiesorinformationand(ii)neitherPartynoritsrespectiveRepresentativesorSubsidiariesshallberequiredtoprovideaccesstoordiscloseinformationwheresuchaccessordisclosurewouldjeopardizetheprotectionofattorney-clientprivilege(itbeingagreedthatthePartiesshallusetheirreasonablebesteffortstocausesuchaccessorinformationtobeprovidedinamannerthatwouldnotresultinsuchjeopardyorcontravention).

4.2 Operation of Opexa’s Business.

(a) ExceptassetforthonSection4.2(a)oftheOpexaDisclosureSchedule,asexpresslyrequiredorpermittedbythisAgreement,orasrequiredbyapplicableLegalRequirements,duringthePre-ClosingPeriod,Opexashall:(i)conductitsbusinessandoperationsintheOrdinaryCourseofBusiness;(ii)continuetopayoutstandingaccountspayableandothercurrentLiabilities(includingpayroll)whendueandpayable;and(iii)conductits

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businessandoperationsincompliancewithallapplicableLegalRequirementsandtherequirementsofallOpexaContracts.

(b) Withoutlimitingthegeneralityoftheforegoing,duringthePre-ClosingPeriod,exceptassetforthonSection4.2(b)oftheOpexaDisclosureSchedule,asexpresslyrequiredorpermittedbythisAgreement,orasrequiredbyapplicableLegalRequirements,Opexashallnot,withoutthepriorwrittenconsentofAcer(whichconsentshallnotbeunreasonablywithheldordelayed):

(i) (A)declare,accrue,setasideorpayanydividendormakeanyotherdistributioninrespectofanysharesofOpexaCapitalStockor(B)repurchase,redeemorotherwisereacquireanysharesofitscapitalstockorothersecurities;

(ii) sell,issueorgrant,encumber,orauthorizetheissuanceof:(A)anycapitalstockorothersecurity(exceptforsharesofOpexaCommonStockissueduponthevalidexerciseofOpexaOptionsorOpexaWarrantsoutstandingasofthedateofthisAgreement),(B)anyoption,warrantorrighttoacquireanycapitalstockoranyothersecurity,(C)anyequity-basedawardorinstrumentconvertibleintoorexchangeableforanycapitalstockorothersecurity,or(D)anydebtsecuritiesoranyrightstoacquireanydebtsecurities;

(iii) amendthecertificateofformation/incorporation,bylawsorothercharterororganizationaldocumentsofOpexaorMergerSub,oreffectorbeapartytoanymerger,consolidation,shareexchange,businesscombination,recapitalization,reclassificationofshares,stocksplit,reversestocksplitorsimilartransaction;

(iv) formanySubsidiaryoracquireanyequityinterestorotherinterestinanyotherEntity;

(v) (A)lendmoneytoanyPerson,or(B)makeanycapitalexpenditureorcommitment;

(vi) (A)adopt,establishorenterintoanyOpexaEmployeePlan,(B)causeorpermitanyOpexaEmployeePlantobeamendedotherthanasrequiredbylaw,includinginordertomakeamendmentsforthepurposesofSection409AoftheCode,subjecttopriorreviewandapproval(withsuchapprovalnottobeunreasonablywithheld,conditionedordelayed)byAcer,(C)hireanyadditionalemployeesorindependentcontractorsorenterintooramendthetermofanyemploymentorconsultingagreementwithanyemployeeorindependentcontractorotherthanasreasonablynecessaryforthecompletionoftheContemplatedTransactions,subjecttopriorreviewandapproval(withsuchapprovalnottobeunreasonablywithheld,conditionedordelayed)byAcer,(D)enterintoanyContractwithalaborunionorcollectivebargainingagreement,(E)exceptasprovidedintheOpexaDisclosureSchedule,payanybonusormakeanyprofit-sharingorsimilarpaymentto(otherthanintheOrdinaryCourseofBusiness),orincreasetheamountofthewages,salary,commissions,fringebenefitsorothercompensationorremunerationpayableto,anyofitsdirectorsoremployees,(F)exceptasprovidedintheOpexaDisclosureSchedule,acceleratethevestingoforentitlementtoanypayment,award,compensationorbenefitwithrespecttoanyOpexaAssociate,(G)exceptasprovidedintheOpexaDisclosureSchedule,payorincreasetheseveranceorchangeofcontrol

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benefitsofferedtoanyOpexaAssociate,or(H)provideormakeanyTax-relatedgross-uppayment;

(vii) exceptasotherwisepermittedunderSection4.2(b)(viii),enterintoanymaterialtransactionoutsidetheOrdinaryCourseofBusiness;

(viii) acquireanymaterialassetnorsell,lease,orotherwiseirrevocablydisposeofanyofitsassetsorproperties,orgrantanyEncumbrancewithrespecttosuchassetsorproperties; provided ,however ,thattheforegoingshallnotprohibitOpexaanditsSubsidiariesfromtransferring,selling,leasing,disposingoforlicensinganyassets(a“PermittedOpexaAssetSale”)solongas(A)anyrequiredshareholderapprovalisobtainednolaterthanconcurrentlywiththeobtainingoftheRequiredOpexaShareholderVote,(B)Opexadoesnotagreetotermsthatarenotreasonableandcustomaryfortransactionsofsimilarsize,typeandscope,(C)theproposedtransaction,ifconsummatedpriortotheEffectiveTime,doesnotcauseOpexatobecomeashellcompanyasdefinedinRule12b-2oftheExchangeAct,and(D)Acerisprovidedwithareasonableamountoftimetoreviewanybindingordefinitiveagreementrelatedtheretoinadvanceofsuchagreement’sexecution;

(ix) (A)make,changeorrevokeanymaterialTaxelection,(B)fileanymaterialamendmenttoanyTaxReturn,(C)adoptorchangeanyaccountingmethodinrespectofTaxes,(D)changeanyannualTaxaccountingperiod,(E)enterintoanyTaxallocationagreement,TaxsharingagreementorTaxindemnityagreement,otherthancommercialcontractsenteredintointheOrdinaryCourseofBusinesswithvendors,customersorlandlords,(F)enterintoanyclosingagreementwithrespecttoanyTax,(G)settleorcompromiseanyclaim,notice,auditreportorassessmentinrespectofmaterialTaxes,(H)applyfororenterintoanyrulingfromanyTaxauthoritywithrespecttoTaxes,(I)surrenderanyrighttoclaimamaterialTaxrefund,or(J)consenttoanyextensionorwaiverofthestatuteoflimitationsperiodapplicabletoanymaterialTaxclaimorassessment;

(x) exceptasotherwisepermittedunderSection4.2(a)(viii),enterinto,amendorterminateanyOpexaContract;

(xi) initiateorsettleanyLegalProceeding;

(xii) aftertheNetCashCalculationisfinalizedpursuanttoSection1.6,incuranyLiabilitiesorotherwisetakeanyactionsotherthanintheOrdinaryCourseofBusinesssoastocausethefinalNetCashCalculationtodiffermateriallyfromtheactualNetCashasoftheClosing(otherthan,subjecttoSection4.2(b)(viii)andthedefinitionof“NetCash,”pursuanttoaPermittedOpexaAssetSale);

(xiii) otherthanasotherwiseexpresslycontemplatedorpermittedbythisAgreement,takeanyactionthatisintendedorthatwouldreasonablybeexpectedto,individuallyorintheaggregate,prevent,materiallydelay,ormateriallyimpedetheconsummationoftheMerger,ortheothertransactionscontemplatedbythisAgreement;or

(xiv) agree,resolveorcommittodoanyoftheforegoing.

4.3 Operation of Acer’s Business.

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(a) ExceptassetforthonSection4.3(a)oftheAcerDisclosureSchedule,asexpresslyrequiredorpermittedbythisAgreement,orasrequiredbyapplicableLegalRequirements,duringthePre-ClosingPeriod,AcershallandshallcauseitsSubsidiariestoconductitsbusinessandoperations:(i)intheOrdinaryCourseofBusiness;and(ii)inmaterialcompliancewithallapplicableLegalRequirementsandtherequirementsofallAcerContractsthatconstituteAcerMaterialContracts.

(b) Withoutlimitingthegeneralityoftheforegoing,duringthePre-ClosingPeriod,exceptassetforthonSection4.3(b)oftheAcerDisclosureSchedule,asexpresslypermittedbythisAgreement,orasrequiredbyapplicableLegalRequirements,Acershallnot,norshallitpermitanyofitsSubsidiariesto,withoutthepriorwrittenconsentofOpexa(whichconsentshallnotbeunreasonablywithheldordelayed):

(i) (A)declare,accrue,setasideorpayanydividendormadeanyotherdistributioninrespectofanysharesofAcerCommonStockor(B)repurchase,redeemorotherwisereacquireanysharesofitscapitalstockorothersecuritiesexceptpursuanttoAcerContractsexistingasofthedateofthisAgreement;

(ii) sell,issueorgrant,orauthorizetheissuanceof:(A)anycapitalstockorothersecurity(exceptinconnectionwiththeAcerPre-ClosingFinancingandforsharesofAcerCommonStockissueduponthevalidexerciseofAcerOptionsoutstandingasofthedateofthisAgreement),(B)anyoption,warrantorrighttoacquireanycapitalstockoranyothersecurity,or(C)anyequity-basedawardorinstrumentconvertibleintoorexchangeableforanycapitalstockorothersecurity;

(iii) amendthecertificateofincorporation,bylawsorothercharterororganizationaldocumentsofAcer(otherthaninconnectionwiththeAcerPre-ClosingFinancing),oreffectorbeapartytoanymerger,consolidation,shareexchange,businesscombination,recapitalization,reclassificationofshares,stocksplit,reversestocksplitorsimilartransaction;

(iv) formanySubsidiaryoracquireanyequityinterestorotherinterestinanyotherEntity;

(v) (A)lendmoneytoanyPerson,(B)incurorguaranteeanyindebtednessforborrowedmoney,otherthantheincurrenceorguaranteeofindebtednessthatispaidoffpriortoorattheClosing,or(C)guaranteeanydebtsecuritiesofothers,or(D)makeanycapitalexpenditureorcommitmentinexcessof$25,000;

(vi) enterintoanyContractwithalaborunionorcollectivebargainingagreement;

(vii) acquireanymaterialassetnorsell,lease,orotherwiseirrevocablydisposeofanyofitsassetsorproperties,orgrantanyEncumbrancewithrespecttosuchassetsorproperties,ineachcase,otherthanintheOrdinaryCourseofBusiness;

(viii) (A)make,changeorrevokeanymaterialTaxelection,(B)fileanymaterialamendmenttoanyTaxReturn,(C)adoptorchangeanyaccountingmethodinrespectof

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Taxes,(D)changeanyannualTaxaccountingperiod,(E)enterintoanyTaxallocationagreement,TaxsharingagreementorTaxindemnityagreement,otherthancommercialcontractsenteredintointheOrdinaryCourseofBusinesswithvendors,customersorlandlords,(F)enterintoanyclosingagreementwithrespecttoanyTax,(G)settleorcompromiseanyclaim,notice,auditreportorassessmentinrespectofmaterialTaxes,(H)applyfororenterintoanyrulingfromanyTaxauthoritywithrespecttoTaxes,(I)surrenderanyrighttoclaimamaterialTaxrefund,or(J)consenttoanyextensionorwaiverofthestatuteoflimitationsperiodapplicabletoanymaterialTaxclaimorassessment;or

(ix) agree,resolveorcommittodoanyoftheforegoing.

4.4 Notification of Certain Matters.

(a) DuringthePre-ClosingPeriod,Opexashall:

(i) promptlynotifyAcerof:(A)anynoticeorothercommunicationfromanyPersonallegingthattheConsentofsuchPersonisormayberequiredinconnectionwithanyoftheContemplatedTransactions;(B)anyLegalProceedingagainst,relatingto,involvingorotherwiseaffectingOpexa,ortotheKnowledgeofOpexa,anydirectororofficerofOpexa,thatiscommencedorassertedagainst,or,totheKnowledgeofOpexa,threatenedagainst,OpexaoranydirectororofficerofOpexa;and(C)anynoticeorothercommunicationfromanyPersonallegingthatanypaymentorotherobligationisorwillbeowedtosuchPersonatanytimebeforeorafterthedateofthisAgreement,exceptforinvoicesorothercommunicationsrelatedtoagreementsordealingsintheOrdinaryCourseofBusinessorpaymentsorobligationsidentifiedinthisAgreement,includingtheOpexaDisclosureSchedule;and

(ii) promptlynotifyAcerinwritingof:(A)thediscoverybyOpexaofanyevent,condition,factorcircumstancethatoccurredorexistedonorpriortothedateofthisAgreementandthatcausedorconstitutesaninaccuracyinanyrepresentationorwarrantymadebyOpexainthisAgreementinamannerthatcausestheconditionsetforthinSection8.1nottobesatisfied;(B)anyevent,condition,factorcircumstancethatoccurs,arisesorexistsafterthedateofthisAgreementandthatwouldcauseorconstituteaninaccuracyinanyrepresentationorwarrantymadebyOpexainthisAgreementinamannerthatcausestheconditionsetforthinSection8.1nottobesatisfiedif:(1)suchrepresentationorwarrantyhadbeenmadeasofthetimeoftheoccurrence,existenceordiscoveryofsuchevent,condition,factorcircumstance;or(2)suchevent,condition,factorcircumstancehadoccurred,arisenorexistedonorpriortothedateofthisAgreement;(C)anybreachofanycovenantorobligationofOpexainamannerthatcausestheconditionsetforthinSection8.2nottobesatisfied;and(D)anyevent,condition,factorcircumstancethatwouldreasonablybeexpectedtomakethetimelysatisfactionofanyoftheconditionssetforthinArticle6,Article7,orArticle8impossibleormateriallylesslikely.NonotificationgiventoAcerpursuanttothisSection4.4(a)shallchange,limitorotherwiseaffectanyoftherepresentations,warranties,covenantsorobligationsofOpexacontainedinthisAgreementortheOpexaDisclosureSchedule.

(b) DuringthePre-ClosingPeriod,Acershall:

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(i) promptlynotifyOpexaof:(A)anynoticeorothercommunicationfromanyPersonallegingthattheConsentofsuchPersonisormayberequiredinconnectionwithanyoftheContemplatedTransactions;(B)anyLegalProceedingagainst,relatingto,involvingorotherwiseaffectingAcer,ortotheKnowledgeofAcer,anydirectororofficerofAcer,thatiscommencedorassertedagainst,or,totheKnowledgeofAcer,threatenedagainst,Acer,anyofitsSubsidiaries,oranydirectororofficerofAcer;and(C)anynoticeorothercommunicationfromanyPersonallegingthatanypaymentorotherobligationisorwillbeowedtosuchPersonatanytimebeforeorafterthedateofthisAgreement,exceptforinvoicesorothercommunicationsrelatedtoagreementsordealingsintheOrdinaryCourseofBusinessorpaymentsorobligationsidentifiedinthisAgreement;and

(ii) promptlynotifyOpexainwriting,of:(A)thediscoverybyAcerofanyevent,condition,factorcircumstancethatoccurredorexistedonorpriortothedateofthisAgreementandthatcausedorconstitutesaninaccuracyinanyrepresentationorwarrantymadebyAcerinthisAgreementinamannerthatcausestheconditionsetforthinSection7.1nottobesatisfied;(B)anyevent,condition,factorcircumstancethatoccurs,arisesorexistsafterthedateofthisAgreementandthatwouldcauseorconstituteaninaccuracyinanyrepresentationorwarrantymadebyAcerinthisAgreementinamannerthatcausestheconditionsetforthinSection7.1nottobesatisfiedif:(1)suchrepresentationorwarrantyhadbeenmadeasofthetimeoftheoccurrence,existenceordiscoveryofsuchevent,condition,factorcircumstance;or(2)suchevent,condition,factorcircumstancehadoccurred,arisenorexistedonorpriortothedateofthisAgreement;(C)anybreachofanycovenantorobligationofAcerinamannerthatcausestheconditionsetforthinSection7.2nottobesatisfied;and(D)anyevent,condition,factorcircumstancethatwouldreasonablybeexpectedtomakethetimelysatisfactionofanyoftheconditionssetforthinArticle6,Article7,orArticle8impossibleormateriallylesslikely.NonotificationgiventoOpexapursuanttothisSection4.4(b)shallchange,limitorotherwiseaffectanyoftherepresentations,warranties,covenantsorobligationsofAcercontainedinthisAgreementortheAcerDisclosureSchedule.

4.5 No Solicitation.

(a) EachPartyagreesthatneitheritnoranyofitsSubsidiariesshall,norshallitnoranyofitsSubsidiariesauthorizeorpermitanyoftheRepresentativesretainedbyitoranyofitsSubsidiariestodirectlyorindirectly:(i)solicit,initiate,respondtoortakeanyactiontofacilitateorencourageanyinquiriesorthecommunication,making,submissionorannouncementofanyAcquisitionProposalorAcquisitionInquiryortakeanyactionthatcouldreasonablybeexpectedtoleadtoanAcquisitionProposalorAcquisitionInquiry;(ii)enterintoorparticipateinanydiscussionsornegotiationswithanyPersonwithrespecttoanyAcquisitionProposalorAcquisitionInquiry;(iii)furnishanyinformationregardingsuchPartytoanyPersoninconnectionwith,inresponseto,relatingtoorforthepurposeofassistingwithorfacilitatinganAcquisitionProposalorAcquisitionInquiry;(iv)approve,endorseorrecommendanyAcquisitionProposal(subjecttoSections5.2and5.3);(v)executeorenterintoanyletterofintentorsimilardocumentoranyContractcontemplatingorotherwiserelatingtoanyAcquisitionTransaction(an“AcquisitionAgreement”);or(vi)grantanywaiverorreleaseunderanyconfidentiality,standstillorsimilaragreement(otherthantotheotherParty).

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(b) NotwithstandinganythingcontainedinSection4.5(a),priortoreceiptoftheRequiredAcerStockholderVote,inthecaseofAcer,ortheRequiredOpexaShareholderVote,inthecaseofOpexa,(i)suchPartymayenterintodiscussionsornegotiationswith,anyPersonthathasmade(andnotwithdrawn)abonafide,unsolicited,AcquisitionProposal,whichsuchParty’sBoardofDirectorsdeterminesingoodfaith,afterconsultationwithitsindependentfinancialadvisor,ifany,anditsoutsidelegalcounsel,constitutes,orwouldreasonablybeexpectedtoresultin,aSuperiorOffer,and(ii)thereafterfurnishtosuchPersonnon-publicinformationregardingsuchPartypursuanttoanexecutedconfidentialityagreementcontainingprovisions(includingnondisclosureprovisions,userestrictions,non-solicitationprovisions,nohireprovisionsand“standstill”provisions)atleastasfavorabletosuchPartyasthosecontainedintheConfidentialityAgreement,butineachcaseoftheforegoingclauses(i)and(ii),onlyif:(A)neithersuchPartynoranyRepresentativeofsuchPartyhasbreachedthisSection4.5;(B)theBoardofDirectorsofsuchPartydeterminesingoodfaithbasedontheadviceofoutsidelegalcounsel,thatthefailuretotakesuchactionwouldreasonablybeexpectedtoresultinabreachofthefiduciarydutiesoftheBoardofDirectorsofsuchPartyunderapplicableLegalRequirements;(C)atleastfive(5)BusinessDayspriortofurnishinganysuchnon-publicinformationto,orenteringintodiscussionswith,suchPerson,suchPartygivestheotherPartywrittennoticeoftheidentityofsuchPersonandofsuchParty’sintentiontofurnishnonpublicinformationto,orenterintodiscussionswith,suchPerson;and(D)atleastfive(5)BusinessDayspriortofurnishinganysuchnon-publicinformationtosuchPerson,suchPartyfurnishessuchnon-publicinformationtoAcerorOpexa,asapplicable(totheextentsuchnon-publicinformationhasnotbeenpreviouslyfurnishedbysuchPartytoAcerorOpexa,asapplicable).Withoutlimitingthegeneralityoftheforegoing,eachPartyacknowledgesandagreesthat,intheeventanyRepresentativeofsuchParty(whetherornotsuchRepresentativeispurportingtoactonbehalfofsuchParty)takesanyactionthat,iftakenbysuchParty,wouldconstituteabreachofthisSection4.5bysuchParty,thetakingofsuchactionbysuchRepresentativeshallbedeemedtoconstituteabreachofthisSection4.5bysuchPartyforpurposesofthisAgreement.

(c) IfanyPartyoranyRepresentativeofsuchPartyreceivesanAcquisitionProposalorAcquisitionInquiryatanytimeduringthePre-ClosingPeriod,thensuchPartyshallpromptly(andinnoeventlaterthantwo(2)BusinessDaysaftersuchPartybecomesawareofsuchAcquisitionProposalorAcquisitionInquiry)advisetheotherPartyinwritingofsuchAcquisitionProposalorAcquisitionInquiry(includingtheidentityofthePersonmakingorsubmittingsuchAcquisitionProposalorAcquisitionInquiry,andthetermsthereof).SuchPartyshallkeeptheotherPartyfullyinformed,onacurrentbasis,inallmaterialrespectswithrespecttothestatusandtermsofanysuchAcquisitionProposalorAcquisitionInquiryandanymodificationorproposedmodificationthereto.Inadditiontotheforegoing,eachPartyshallprovidetheotherPartywithatleastfive(5)BusinessDays’writtennoticeofameetingofitsboardofdirectors(oranycommitteethereof)atwhichitsboardofdirectors(oranycommitteethereof)isreasonablyexpectedtoconsideranAcquisitionProposalorAcquisitionInquiryithasreceived.

(d) EachPartyshallandshallcauseitsrespectiveRepresentativesto,ceaseimmediatelyandcausetobeterminated,andshallnotauthorizeorknowinglypermitanyofitsortheirRepresentativestocontinue,anyandallexistingactivities,discussionsornegotiations,ifany,withanythirdpartyconductedpriortothedatehereofwithrespecttoanyAcquisitionProposalandshalluseitsreasonablebesteffortstocauseanysuchthirdparty(orits

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Representatives)inpossessionofnon-publicinformationinrespectofsuchPartyoritsSubsidiariesthatwasfurnishedbyoronbehalfofsuchPartyoritsSubsidiariestoreturnordestroy(andconfirmdestructionof)allsuchinformation.

ARTICLE 5

ADDITIONAL AGREEMENTS OF THE PARTIES

5.1 Registration Statement; Proxy Statement / Prospectus / Information Statement.

(a) AspromptlyaspracticableafterthedateofthisAgreement,thePartiesshallprepareandcausetobefiledwiththeSECtheProxyStatement/Prospectus/InformationStatementandOpexashallprepareandcausetobefiledwiththeSECtheFormS-4RegistrationStatement,inwhichtheProxyStatement/Prospectus/InformationStatementwillbeincludedasaprospectus.

(b) OpexacovenantsandagreesthattheProxyStatement/Prospectus/InformationStatement,includinganyproformafinancialstatementsincludedtherein(andthelettertoshareholders,noticeofmeetingandformofproxyincludedtherewith),willnot,atthetimethattheProxyStatement/Prospectus/InformationStatementoranyamendmentorsupplementtheretoisfiledwiththeSECorisfirstmailedtotheOpexaShareholders,atthetimeoftheOpexaShareholders’MeetingandattheEffectiveTime,containanyuntruestatementofamaterialfactoromittostateanymaterialfactrequiredtobestatedthereinornecessaryinordertomakethestatementsmadetherein,inlightofthecircumstancesunderwhichtheyweremade,notmisleading.Notwithstandingtheforegoing,Opexamakesnocovenant,representationorwarrantywithrespecttostatementsmadeintheProxyStatement/Prospectus/InformationStatement(andthelettertoshareholders,noticeofmeetingandformofproxyincludedtherewith),ifany,basedoninformationfurnishedinwritingbyAcerspecificallyforinclusiontherein.EachofthePartiesshallusecommerciallyreasonableeffortstocausetheFormS-4RegistrationStatementandtheProxyStatement/Prospectus/InformationStatementtocomplywiththeapplicablerulesandregulationspromulgatedbytheSECinallmaterialrespects.

(c) OpexashallnotifyAcerpromptlyofthereceiptofanycommentsfromtheSECorthestaffoftheSECandofanyrequestbytheSECorthestaffoftheSECforamendmentsorsupplementstotheProxyStatement/Prospectus/InformationStatementortheFormS-4RegistrationStatementorforadditionalinformationandshallsupplyAcerwithcopiesof(i)allcorrespondencebetweenOpexaoranyofitsRepresentatives,ontheonehand,andtheSECorthestaffoftheSEC,ontheotherhand,withrespecttotheProxyStatement/Prospectus/InformationStatement,theFormS-4RegistrationStatementortheContemplatedTransactionsand(ii)allordersoftheSECrelatingtotheFormS-4RegistrationStatement.OpexashalluseitscommerciallyreasonableeffortstorespondaspromptlyasreasonablypracticabletoanycommentsoftheSECorthestaffoftheSECwithrespecttotheProxyStatement/Prospectus/InformationStatementandFormS-4RegistrationStatement,andAceranditscounselareasonableopportunitytoparticipateintheformulationofanyresponsetoanysuchcommentsoftheSECoritsstaff.PriortotheFormS-4RegistrationStatementbeingdeclaredeffective,(1)AcershalluseitscommerciallyreasonableeffortstoexecuteanddelivertoFoleyHoagLLP

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(“Foley”)andtoPillsburyWinthropShawPittmanLLP(“Pillsbury”)theapplicable“TaxRepresentationLetter”referencedinSection5.11(c);and(2)OpexashalluseitscommerciallyreasonableeffortstoexecuteanddelivertoPillsburyandtoFoleytheapplicable“TaxRepresentationLetter”referencedinSection5.11(c).FollowingthedeliveryoftheTaxRepresentationLetterspursuanttotheprecedingsentence,(A)AcershalluseitscommerciallyreasonableeffortstocauseFoleytodelivertoitataxopinionsatisfyingtherequirementsofItem601ofRegulationS-KundertheSecuritiesAct;and(B)OpexashalluseitscommerciallyreasonableeffortstocausePillsburytodelivertoitataxopinionsatisfyingtherequirementsofItem601ofRegulationS-KundertheSecuritiesAct.Inrenderingsuchopinions,eachofsuchcounselshallbeentitledtorelyontheTaxRepresentationLettersreferredtointhisSection5.1(c)andSection5.11(c).OpexashalluseitscommerciallyreasonableeffortstohavetheFormS-4RegistrationStatementdeclaredeffectivebytheSECundertheSecuritiesActaspromptlyaspracticableafteritisfiledwiththeSEC.Nofilingof,oramendmentorsupplementto,theFormS-4RegistrationStatementwillbemadebyOpexa,andnofilingof,oramendmentorsupplementto,theProxyStatement/Prospectus/InformationStatementwillbemadebyOpexa,ineachcase,withoutprovidingAcerareasonableopportunitytoreviewandcommentthereon.EachPartyshallpromptlyfurnishtotheotherPartyallinformationconcerningsuchPartyandsuchParty’sSubsidiariesandsuchParty’sshareholders/stockholdersthatmayberequiredorreasonablyrequestedinconnectionwithanyactioncontemplatedbythisSection5.1.IfanyeventrelatingtoAceroccurs,orifAcerbecomesawareofanyinformation,thatshouldbedisclosedinanamendmentorsupplementtotheFormS-4RegistrationStatementortheProxyStatement/Prospectus/InformationStatement,thenAcershallpromptlyinformOpexathereofandshallcooperatefullywithOpexainfilingsuchamendmentorsupplementwiththeSECand,ifappropriate,inmailingsuchamendmentorsupplementtoOpexa’sshareholders.

(d) PriortotheEffectiveTime,OpexashallusecommerciallyreasonableeffortstoobtainallregulatoryapprovalsneededtoensurethattheOpexaCommonStocktobeissuedintheMergershallberegisteredorqualifiedorexemptfromregistrationorqualificationunderthesecuritieslawofeveryjurisdictionoftheUnitedStatesinwhichanyregisteredholderofAcerCapitalStockhasanaddressofrecordontherecorddatefordeterminingthestockholdersentitledtonoticeofandtovotepursuanttotheAcerStockholderWrittenConsent.

(e) AcershallreasonablycooperatewithOpexaandprovide,andrequireitsRepresentativestoprovide,OpexaanditsRepresentativeswithalltrue,correctandcompleteinformationregardingAcerthatisrequiredbyapplicableLegalRequirementstobeincludedintheFormS-4RegistrationStatementorreasonablyrequestedfromAcertobeincludedintheFormS-4RegistrationStatement.

5.2 Acer Stockholder Written Consent.

(a) PromptlyaftertheS-4RegistrationStatementhasbeendeclaredeffectivebytheSECundertheSecuritiesAct,andinanyeventnolaterthanfive(5)BusinessDaysthereafter,AcershallobtaintheAcerStockholderWrittenConsentforpurposesof(i)adoptingthisAgreement,andapprovingtheMerger,thePreferredStockConversion,theAcerPre-ClosingFinancing,andtheotheractionscontemplatedbythisAgreement(the“AcerStockholderMatters”);(ii)acknowledgingthattheapprovalgiventherebyisirrevocableandthatsuchstockholderisawareofitsrightstodemandappraisalforitssharespursuanttoSection

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262oftheDGCL,acopyofwhichwasattachedthereto,andthatsuchstockholderhasreceivedandreadacopyofSection262oftheDGCL;and(iii)acknowledgingthatbyitsapprovaloftheMergeritisnotentitledtoappraisalrightswithrespecttoitssharesinconnectionwiththeMergerandtherebywaivesanyrightstoreceivepaymentofthefairvalueofitscapitalstockundertheDGCL.

(b) Aceragreesthat,subjecttoSection5.2(c):(i)theAcerBoardofDirectorsshallrecommendthatAcerStockholdersvotetoapprovetheAcerStockholderMatters(the“AcerBoardRecommendation”)andshallusecommerciallyreasonableeffortstosolicitsuchapprovalwithinthetimesetforthinSection5.2(a);and(ii)(A)theAcerBoardRecommendationshallnotbewithdrawnormodifiedinamanneradversetoOpexa,andnoresolutionbytheAcerBoardofDirectorsoranycommitteethereoftowithdrawormodifytheAcerBoardRecommendationinamanneradversetoOpexashallbeadoptedorproposedand(B)theAcerBoardofDirectorsshallnotrecommendanyAcquisitionTransaction(collectivelyan“AcerBoardAdverseRecommendationChange”).

(c) Notwithstandingtheforegoing,atanytimepriortothereceiptoftheRequiredAcerStockholderVote,theAcerBoardofDirectorsmaymakeanAcerBoardAdverseRecommendationChange,if:(i)theAcerBoardofDirectorshasreceivedanAcquisitionProposalthattheAcerBoardofDirectorshasdeterminedinitsreasonable,goodfaithjudgment,afterconsultationwithAcer’soutsidelegalcounsel,constitutesaSuperiorOfferor(ii)asaresultofamaterialdevelopmentorchangeincircumstances(otherthananAcquisitionProposal)thataffectsthebusiness,assetsoroperationsofAcerthatoccursorarisesafterthedateofthisAgreementthatwasneitherknowntoAcerortheAcerBoardofDirectorsnorreasonablyforeseeableasofthedateofthisAgreement(an“AcerInterveningEvent”),theAcerBoardofDirectorsdeterminesinitsreasonable,goodfaithjudgment,afterconsultationwithAcer’soutsidelegalcounsel,thatanAcerBoardAdverseRecommendationChangeisrequiredinorderfortheAcerBoardofDirectorstocomplywithitsfiduciaryobligationstotheAcerStockholdersunderapplicableLegalRequirements;provided, however ,thatpriortoAcertakinganyactionpermittedunderthisSection5.2(c),(A)inthecaseofaSuperiorOffer,(1)AcermustpromptlynotifyOpexa,inwriting,atleastfive(5)BusinessDays(the“NoticePeriod”)beforemakinganAcerBoardAdverseRecommendationChange,ofitsintentiontotakesuchactionwithrespecttoaSuperiorOffer,whichnoticeshallstateexpresslythatAcerhasreceivedanAcquisitionProposalthattheAcerBoardofDirectorsintendstodeclareaSuperiorOfferandthattheAcerBoardofDirectorsintendstomakeanAcerBoardAdverseRecommendationChange,(2)Acerattachestosuchnoticethemostcurrentversionoftheproposedagreement(whichversionshallbeupdatedonapromptbasis)andtheidentityofthethirdpartymakingsuchSuperiorOffer,and(3)AcernegotiateswithOpexaingoodfaithtomakesuchadjustmentsinthetermsandconditionsofthisAgreementsothatsuchAcquisitionProposalceasestoconstituteaSuperiorOffer,ifOpexa,initsdiscretion,proposestomakesuchadjustments(itbeingagreedthatintheeventthat,aftercommencementoftheNoticePeriod,thereisanymaterialrevisiontothetermsofaSuperiorOffer,theNoticePeriodshallbeextended,ifapplicable,toensurethatatleastthree(3)BusinessDaysremainsintheNoticePeriodsubsequenttothetimeAcernotifiesOpexaofanysuchmaterialrevision(itbeingunderstoodthattheremaybemultipleextensions);or(B)inthecaseofanAcerInterveningEvent,(1)AcerpromptlynotifiesOpexa,inwriting,withintheNoticePeriodbeforemakinganAcerBoardAdverseRecommendationChange,whichnoticeshallstateexpresslythematerialfactsandcircumstancesrelatedtotheapplicableAcer

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InterveningEventandthattheAcerBoardofDirectorsintendstomakeanAcerBoardAdverseRecommendationChangeand(2)AcernegotiateswithOpexaingoodfaithtomakesuchadjustmentsinthetermsandconditionsofthisAgreementsothatsuchAcerInterveningEventceasestonecessitateanAcerBoardAdverseRecommendationChangewithrespecttoAcer’sfiduciaryduties,ifOpexa,initsdiscretion,proposestomakesuchadjustments(itbeingagreedthatintheeventthat,aftercommencementoftheNoticePeriod,thereisanymaterialdevelopmentinanAcerInterveningEvent,theNoticePeriodshallbeextended,ifapplicable,toensurethatatleastthree(3)BusinessDaysremainsintheNoticePeriodsubsequenttothetimeAcernotifiesOpexaofanysuchmaterialdevelopment(itbeingunderstoodthattheremaybemultipleextensions).

(d) UnlesstheAcerBoardofDirectorshaseffectedanAcerBoardAdverseRecommendationChangeinaccordancewithSection5.2(c),Acer’sobligationtosolicittheconsentofitsstockholderstosigntheAcerStockholderWrittenConsentinaccordancewithSection5.2(a)shallnotbelimitedorotherwiseaffectedbythecommencement,disclosure,announcementorsubmissionofanySuperiorOfferorotherAcquisitionProposal,orbyanywithdrawalormodificationoftheAcerBoardRecommendation.

5.3 Opexa Shareholders’ Meeting.

(a) PromptlyaftertheFormS-4RegistrationStatementhasbeendeclaredeffectivebytheSECundertheSecuritiesAct,Opexashall(i)takeallactionnecessaryunderapplicableLegalRequirementstocall,givenoticeofandholdameetingoftheholdersofOpexaCommonStockforthepurposeofseekingapprovalof(A)theissuanceofsharesofOpexaCommonStocktotheAcerStockholderspursuanttothetermsofthisAgreement,(B)thechangeofcontrolofOpexaresultingfromtheMerger,(C)ifrequestedbyAcerpriortothefilingwiththeSECoftheProxyStatement/Prospectus/InformationStatement,theamendmentofOpexa’scertificateofformationtoeffecttheNASDAQReverseSplit,(D)theamendmentofOpexa’scertificateofformationtoeffectthenamechangeofOpexa,(E)theamendmentofthe2010PlantoincreasethenumberofsharesreservedthereundertoanamounttoberecommendedbytheAcerBoardofDirectorsoracommitteethereof,(F)anyPermittedOpexaAssetSale,totheextentrequiredandnotpreviouslyapprovedbytheOpexaShareholdersand(G)inaccordancewithSection14AoftheExchangeActandtheapplicableSECrulesissuedthereunder,seekingadvisoryapprovalofaproposaltotheOpexaShareholdersforanon-binding,advisoryvotetoapprovecertaincompensationthatmaybecomepayabletoOpexa’snamedexecutedofficerinconnectionwiththecompletionoftheMerger,ifapplicable(thematterscontemplatedbytheforegoingclauses(A)–(G),collectively,the“OpexaShareholderMatters”);and(ii)mailtotheOpexaShareholdersasoftherecorddateestablishedforshareholders’meetingofOpexa,theProxyStatement/Prospectus/InformationStatement;provided, however, thatinnoeventshallsuchmeetingtakeplacemorethansixty(60)calendardaysafterthedatetheS-4RegistrationStatementisdeclaredeffectivebytheSEC(suchmeeting,the“OpexaShareholders’Meeting”).

(b) Opexaagreesthat,subjecttoSection5.3(c):(i)theOpexaBoardofDirectorsshallrecommendthattheholdersofOpexaCommonStockvotetoapprovetheOpexaShareholderMatters;(ii)theProxyStatement/Prospectus/InformationStatementshallincludeastatementtotheeffectthattheOpexaBoardofDirectorsrecommendsthatOpexaShareholdervotetoapprovetheOpexaShareholderMatters(the“OpexaBoardRecommendation”);(iii)the

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OpexaBoardofDirectorsshallusecommerciallyreasonableeffortstosolicitsuchapprovalwithinthetimeframesetforthinSection5.3(a)above;and(iv)(A)theOpexaBoardRecommendationshallnotbewithdrawnormodifiedinamanneradversetoAcer,andnoresolutionbytheOpexaBoardofDirectororanycommitteethereoftowithdrawormodifytheOpexaBoardRecommendationinamanneradversetoAcershallbeadoptedorproposedand(B)theOpexaBoardofDirectorsshallnotrecommendanyAcquisitionTransaction(collectivelya“OpexaBoardAdverseRecommendationChange”).

(c) Notwithstandingtheforegoing,atanytimepriortothereceiptoftheRequiredOpexaShareholderVote,theOpexaBoardofDirectorsmaymakeanOpexaBoardAdverseRecommendationChange,if:(i)theOpexaBoardofDirectorshasreceivedanAcquisitionProposalthattheOpexaBoardofDirectorshasdeterminedinitsreasonable,goodfaithjudgment,afterconsultationwithOpexa’soutsidelegalcounsel,constitutesaSuperiorOfferor(ii)asaresultofamaterialdevelopmentorchangeincircumstances(otherthananAcquisitionProposal)thataffectsthebusiness,assetsoroperationsofOpexathatoccursorarisesafterthedateofthisAgreementthatwasneitherknowntoOpexaortheOpexaBoardofDirectorsnorreasonablyforeseeableasofthedateofthisAgreement(a“OpexaInterveningEvent”),theOpexaBoardofDirectorsdeterminesinitsreasonable,goodfaithjudgment,afterconsultationwithOpexa’soutsidelegalcounsel,thatanOpexaBoardAdverseRecommendationChangeisrequiredinorderfortheOpexaBoardofDirectorstocomplywithitsfiduciaryobligationstotheOpexaShareholdersunderapplicableLegalRequirements;provided, however ,thatpriortoOpexatakinganyactionpermittedunderthisSection5.3(c),(A)inthecaseofaSuperiorOffer,(1)OpexamustpromptlynotifyAcer,inwriting,withintheNoticePeriodbeforemakinganOpexaBoardAdverseRecommendationChange,ofitsintentiontotakesuchactionwithrespecttoaSuperiorOffer,whichnoticeshallstateexpresslythatOpexahasreceivedanAcquisitionProposalthattheOpexaBoardofDirectorsintendstodeclareaSuperiorOfferandthattheOpexaBoardofDirectorsintendstomakeanOpexaBoardAdverseRecommendationChange,(2)Opexaattachestosuchnoticethemostcurrentversionoftheproposedagreement(whichversionshallbeupdatedonapromptbasis)andtheidentityofthethirdpartymakingsuchSuperiorOffer,and(3)OpexanegotiateswithAceringoodfaithtomakesuchadjustmentsinthetermsandconditionsofthisAgreementsothatsuchAcquisitionProposalceasestoconstituteaSuperiorOffer,ifAcer,initsdiscretion,proposestomakesuchadjustments(itbeingagreedthatintheeventthat,aftercommencementoftheNoticePeriod,thereisanymaterialrevisiontothetermsofaSuperiorOffer,theNoticePeriodshallbeextended,ifapplicable,toensurethatatleastthree(3)BusinessDaysremainsintheNoticePeriodsubsequenttothetimeOpexanotifiesAcerofanysuchmaterialrevision(itbeingunderstoodthattheremaybemultipleextensions);or(B)inthecaseofanOpexaInterveningEvent,(1)OpexapromptlynotifiesAcer,inwriting,withintheNoticePeriodbeforemakinganOpexaBoardAdverseRecommendationChange,whichnoticeshallstateexpresslythematerialfactsandcircumstancesrelatedtotheapplicableOpexaInterveningEventandthattheOpexaBoardofDirectorsintendstomakeanOpexaAdverseRecommendationChange,and(2)OpexanegotiateswithAceringoodfaithtomakesuchadjustmentsinthetermsandconditionsofthisAgreementsothatsuchOpexaInterveningEventceasestonecessitateanOpexaBoardAdverseRecommendationChangewithrespecttoOpexa’sfiduciaryduties,ifAcer,initsdiscretion,proposestomakesuchadjustments(itbeingagreedthatintheeventthat,aftercommencementoftheNoticePeriod,thereisanymaterialdevelopmentinanOpexaInterveningEvent,theNoticePeriodshallbeextended,ifapplicable,toensurethatatleastthree(3)BusinessDaysremainsintheNoticePeriod

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subsequenttothetimeOpexanotifiesAcerofanysuchmaterialdevelopment(itbeingunderstoodthattheremaybemultipleextensions).

(d) UnlesstheOpexaBoardofDirectorshaseffectedanOpexaBoardAdverseRecommendationChangeinaccordancewithSection5.3(c),Opexa’sobligationtocall,givenoticeofandholdtheOpexaShareholders’MeetinginaccordancewithSection5.3(a)shallnotbelimitedorotherwiseaffectedbythecommencement,disclosure,announcementorsubmissionofanySuperiorOfferorAcquisitionProposal,orbyanywithdrawalormodificationoftheOpexaBoardRecommendation.

(e) NothingcontainedinthisAgreementshallprohibitOpexaoritsBoardofDirectorsfrom(i)takinganddisclosingtotheOpexaShareholdersapositionascontemplatedbyRule14e-2(a)undertheExchangeActorcomplyingwiththeprovisionsofRule14d-9undertheExchangeAct(otherthanRule14d-9(f)undertheExchangeAct),(ii)makinganydisclosuretotheOpexaShareholdersiftheOpexaBoardofDirectorsdeterminesingoodfaith,afterconsultationwithitsoutsidelegalcounsel,thatthefailuretomakesuchdisclosurewouldbeinconsistentwithitsfiduciarydutiestotheOpexaShareholdersunderapplicableLegalRequirements,and(iii)makinga“stop,lookandlisten”communicationtotheOpexaShareholderspursuanttoRule14d-9(f)undertheExchangeAct,provided, however, that(A)inthecaseofeachoftheforegoingclauses“(i)”and“(ii),”anysuchdisclosureorpublicstatementshallbedeemedtobeanOpexaBoardAdverseRecommendationChangesubjecttothetermsandconditionsofthisAgreementunlesstheOpexaBoardofDirectorsreaffirmstheOpexaBoardRecommendationinsuchdisclosureorpublicstatementorwithinfiveBusinessDaysofsuchdisclosureorpublicstatement;(B)inthecaseofclause“(iii),”anysuchdisclosureorpublicstatementshallbedeemedtobeanOpexaBoardAdverseRecommendationChangesubjecttothetermsandconditionsofthisAgreementunlesstheOpexaBoardofDirectorsreaffirmstheOpexaBoardRecommendationinsuchdisclosureorpublicstatementorwithinten(10)BusinessDaysofsuchdisclosureorpublicstatement;and(C)OpexashallnoteffectanOpexaBoardAdverseRecommendationChangeunlessspecificallypermittedpursuanttothetermsofSection5.3(c).

5.4 Regulatory Approvals.

(a) EachPartyshallusecommerciallyreasonableeffortstotake,orcausetobetaken,allactionsnecessarytocomplypromptlywithallLegalRequirementsthatmaybeimposedonsuchPartywithrespecttotheContemplatedTransactionsand,subjecttotheconditionssetforthinArticle6hereof,toconsummatetheContemplatedTransactions,aspromptlyaspracticable.Infurtheranceandnotinlimitationoftheforegoing,eachPartyheretoagreestofileorotherwisesubmit,assoonaspracticableafterthedateofthisAgreement,butinanyeventnolaterthanten(10)BusinessDaysafterthedatehereof,allapplications,notices,reportsandotherdocumentsreasonablyrequiredtobefiledbysuchPartywithorotherwisesubmittedbysuchPartytoanyGovernmentalBodywithrespecttotheContemplatedTransactions,andtosubmitpromptlyanyadditionalinformationrequestedbyanysuchGovernmentalBody.Withoutlimitingthegeneralityoftheforegoing,thePartiesshallprepareandfile,ifandasrequired,(a)theNotificationandReportFormspursuanttotheHSRActand(b)anynotificationorotherdocumenttobefiledinconnectionwiththeMergerunderanyapplicableforeignLegalRequirementrelatingtoantitrustorcompetitionmatters.Acerand

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Opexashallrespondaspromptlyasispracticabletorespondincompliancewith:(i)anyinquiriesorrequestsreceivedfromtheFederalTradeCommissionortheDepartmentofJusticeforadditionalinformationordocumentation;and(ii)anyinquiriesorrequestsreceivedfromanystateattorneygeneral,foreignantitrustorcompetitionauthorityorotherGovernmentalBodyinconnectionwithantitrustorcompetitionmatters.

(b) EachofthePartiesshalluseitscommerciallyreasonableeffortsto(i)cooperateinallrespectswitheachotherinconnectionwithtimelymakingallrequiredfilingsandsubmissionsandtimelyobtainingallrelatedconsents,permits,authorizationsorapprovalspursuanttoSection5.4(a);and(ii)keepAcerorOpexa,asapplicable,informedinallmaterialrespectsandonareasonablytimelybasisofanycommunicationreceivedbysuchPartyfrom,orgivenbysuchPartyto,theFederalTradeCommission,theDepartmentofJusticeoranyotherGovernmentalBodyrelatingtotheContemplatedTransactions.SubjecttoapplicableLegalRequirementsrelatingtotheexchangeofinformation,eachPartyshall,totheextentpracticable,givetheotherpartyreasonableadvancenoticeofallmaterialcommunicationswithanyGovernmentalBodyrelatingtotheContemplatedTransactionsandeachPartyshallhavetherighttoattendorparticipateinmaterialconferences,meetingsandtelephoneorothercommunicationsbetweentheotherPartiesandregulatorsconcerningtheContemplatedTransactions.

(c) NotwithstandingSections5.4(a)through5.4(b)oranyotherprovisionofthisAgreementtothecontrary,innoeventshalleitherPartyberequiredtoagreeto(i)divest,license,holdseparateorotherwisedisposeof,encumberorallowathirdpartytoutilize,anyportionofitsortheirrespectivebusinesses,assetsorcontractsor(ii)takeanyotheractionthatmayberequiredorrequestedbyanyGovernmentalBodyinconnectionwithobtainingtheconsents,authorizations,ordersorapprovalscontemplatedbythisSection5.4that,wouldhaveanadverseimpact,inanymaterialrespect,onanyoftheParties.

5.5 Acer Options.

(a) AttheEffectiveTime,eachAcerOptionthatisoutstandingandunexercisedimmediatelypriortotheEffectiveTimeunderthe2013Plan,whetherornotvested,shallbeassumedbyOpexaandconvertedintoanoptiontopurchaseOpexaCommonStock,andOpexashallassumethe2013PlanandeachsuchAcerOptioninaccordancewiththeterms(asineffectasofthedateofthisAgreement)ofthe2013PlanandthetermsofthestockoptionagreementbywhichsuchAcerOptionisevidenced.AllrightswithrespecttoAcerCommonStockunderAcerOptionsassumedbyOpexashallthereuponbeconvertedintorightswithrespecttoOpexaCommonStock.Accordingly,fromandaftertheEffectiveTime:(i)eachAcerOptionassumedbyOpexamaybeexercisedsolelyforsharesofOpexaCommonStock;(ii)thenumberofsharesofOpexaCommonStocksubjecttoeachAcerOptionassumedbyOpexashallbedeterminedbymultiplying(A)thenumberofsharesofAcerCommonStockthatweresubjecttosuchAcerOption,asineffectimmediatelypriortotheEffectiveTime,by(B)theExchangeRatioandroundingtheresultingnumberdowntothenearestwholenumberofsharesofOpexaCommonStock;(iii)thepershareexercisepricefortheOpexaCommonStockissuableuponexerciseofeachAcerOptionassumedbyOpexashallbedeterminedbydividing(A)thepershareexercisepriceofAcerCommonStocksubjecttosuchAcerOption,asineffectimmediatelypriortotheEffectiveTime,by(B)theExchangeRatioandroundingtheresulting

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exercisepriceuptothenearestwholecent;and(iv)anyrestrictionontheexerciseofanyAcerOptionassumedbyOpexashallcontinueinfullforceandeffectandtheterm,exercisability,vestingscheduleandotherprovisionsofsuchAcerOptionshallotherwiseremainunchanged;provided, however ,that:(A)totheextentprovidedunderthetermsofanAcerOption,suchAcerOptionassumedbyOpexainaccordancewiththisSection5.5(a)shall,inaccordancewithitsterms,besubjecttofurtheradjustmentasappropriatetoreflectanystocksplit,divisionorsubdivisionofshares,stockdividend,reversestocksplit,consolidationofshares,reclassification,recapitalizationorothersimilartransactionwithrespecttoOpexaCommonStocksubsequenttotheEffectiveTime;and(B)theOpexaBoardofDirectorsoracommitteethereofshallsucceedtotheauthorityandresponsibilityoftheAcerBoardofDirectorsoranycommitteethereofwithrespecttoeachAcerOptionassumedbyOpexa.NotwithstandinganythingtothecontraryinthisSection5.5(a),theconversionofeachAcerOption(regardlessofwhethersuchoptionqualifiesasan“incentivestockoption”withinthemeaningofSection422oftheCode)intoanoptiontopurchasesharesofOpexaCommonStockshallbemadeinamannerconsistentwithTreasuryRegulationSection1.424-1,suchthattheconversionofanAcerOptionshallnotconstitutea“modification”ofsuchAcerOptionforpurposesofSection409AorSection424oftheCode.

(b) OpexashallfilewiththeSEC,nolaterthanthirty(30)calendardaysaftertheEffectiveTime,aregistrationstatementonFormS-8,ifavailableforusebyOpexa,relatingtothesharesofOpexaCommonStockissuablewithrespecttoAcerOptionsassumedbyOpexainaccordancewithSection5.5(a).

5.6 Opexa Employee and Benefits Matters; Opexa Options.

(a) UnlessotherwiseagreedinwritingbyAcerpursuanttowrittennoticeprovidedtoOpexanolaterthanthree(3)calendardayspriortotheClosingDate,effectivenolaterthantheBusinessDayimmediatelypriortotheClosingDate,Opexashall,andshallcauseanyofitsSubsidiariesto,terminatetheemploymentandserviceofeachOpexaAssociate(the“TerminatedOpexaAssociates”)suchthatneitherOpexanoranyOpexaSubsidiaryshallhaveanyOpexaAssociateinitsemployorserviceasoftheEffectiveTime.AsaconditiontopaymentofanyTerminatedOpexaAssociatePaymenttoaTerminatedOpexaAssociateandpriortotheClosingDate,OpexawillusecommerciallyreasonableeffortstoobtainfromeachTerminatedOpexaAssociateaneffectivereleaseofclaimsinaformapprovedbyAcer,whichapprovalshallnotbeunreasonablywithheld,conditionedordelayed.PriortotheClosing,Opexashallusecommerciallyreasonableeffortstocomply,inallmaterialrespects,withalloftherequirementsoftheWARNActandanyapplicablestateLegalRequirementequivalentwithrespecttotheTerminatedOpexaAssociates.Schedule5.6(a)(ii)setsforth,withrespecttoeachTerminatedOpexaAssociate,Opexa’sgoodfaithestimateoftheamountofallchangeofcontrolpayments,severancepayments,terminationorsimilarpayments,retentionpayments,bonusesandotherpaymentsandbenefits(includinganyCOBRAcosts),owedtoortobepaidorprovidedtoeachTerminatedOpexaAssociate,andtheamountbywhichanyofsuchTerminatedOpexaAssociate’scompensationorbenefitsmaybeacceleratedorincreased,ineachcase,whetherunderanyOpexaEmployeePlanorotherwise,asaresultof(i)theexecutionofthisAgreement,(ii)theconsummationoftheContemplatedTransactions,or(iii)theterminationofemploymentorserviceofsuchTerminatedOpexaAssociate(together,the“TerminatedOpexaAssociatePayments”).

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(b) EachOpexaOptionthatisoutstandingandunexercisedimmediatelypriortotheEffectiveTime,whetherunderthe2010Planorotherwiseandwhetherornotvestedorexercisable,andeachOpexaRSUthatisoutstandingandhasnotbeensettledasoftheEffectiveTime,whetherunderthe2010Planorotherwise,shallbe(i)fullyexercisableimmediatelypriortotheEffectiveTime(i.e.,100%accelerationofvesting)and(ii)otherwisecanceledandextinguishedattheEffectiveTimewithouttherighttoreceiveanyconsideration.PriortotheEffectiveTime,theOpexaBoardofDirectorswilladoptappropriateresolutions(ifrequiredinasmuchastheOpexaBoardofDirectorswillhaveapprovedthisAgreement,includingthisSection5.6(b)),whichdraftresolutions(ifapplicable)shallbeprovidedtoAcerforreasonablereviewandapprovalbyAcerpriortoadoptionbytheOpexaBoardofDirectorsandnolaterthanfivecalendardayspriortotheClosingDate,andwillhavetakenallotheractionsnecessaryandappropriate(underthe2010Plan,theOpexaOptions,theOpexaRSUsandotherwise)toeffectuatetheprovisionsofthisSection5.6(b)andtoensurethat,fromandaftertheEffectiveTime,holdersofOpexaOptionsandOpexaRSUshavenorightswithrespectthereto.

(c) EffectivenolaterthanthedayimmediatelyprecedingtheClosingDate,Opexashallterminate(i)allOpexaEmployeePlansthatare“employeebenefitplans”withinthemeaningofERISA,includingbutnotlimitedtoanyOpexaEmployeePlansintendedtoincludeaCodeSection401(k)arrangement(each,a“Opexa401(k)Plan”),and(ii)eachotherOpexaEmployeePlansetforthonSchedule5.6(c)attachedheretounlesswrittennoticeisprovidedbyAcertoOpexanolaterthanthree(3)calendardayspriortotheClosingDate,instructingOpexanottoterminateanysuchOpexaEmployeePlan.OpexashallprovideAcerwithevidencethatsuchOpexaEmployeePlan(s)havebeenterminated(effectivenolaterthanthedayimmediatelyprecedingtheClosingDate)pursuanttoresolutionsoftheOpexaBoardofDirectors.TheformandsubstanceofsuchresolutionsshallbesubjecttoreviewandapprovalofAcer.OpexaalsoshalltakesuchotheractionsinfurtheranceofterminatingsuchOpexaEmployeePlan(s)asAcermayreasonablyrequire.IntheeventthatterminationoftheOpexa401(k)Planswouldreasonablybeanticipatedtotriggerliquidationcharges,surrenderchargesorotherfeesthenOpexashalltakesuchactionsasarenecessarytoreasonablyestimatetheamountofsuchchargesand/orfeesandprovidesuchestimateinwritingtoAcernolaterthanfourteen(14)calendardayspriortotheClosingDate.

(d) ThisSection5.6shallbebindinguponandinuresolelytothebenefitofeachofthepartiestothisAgreement.NothinginthisSection5.6,expressorimplied,will(i)constituteorbetreatedasanamendmentofanyOpexaEmployeePlanorAcerEmployeePlan(oranundertakingtoamendanysuchplan),(ii)prohibitOpexa,anyOpexaAffiliate,Acer,oranyAcerAffiliatefromamending,modifyingorterminatinganyOpexaEmployeePlanorAcerEmployeePlanpursuantto,andinaccordancewith,thetermsthereof,or(iii)conferanyrightsorbenefitsonanyPersonotherthanOpexaandAcer.

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5.7 Indemnification of Officers and Directors.

(a) FromtheEffectiveTimethroughthesixth(6th)anniversaryofthedateonwhichtheEffectiveTimeoccurs,eachofOpexaandtheSurvivingCorporationshall,jointlyandseverally,indemnifyandholdharmlesseachpersonwhoisnow,orhasbeenatanytimepriortothedatehereof,orwhobecomespriortotheEffectiveTime,adirectororofficerofOpexaorAcer(the“D&OIndemnifiedParties”),againstallclaims,losses,liabilities,damages,judgments,finesandreasonablefees,costsandexpenses,includingattorneys’feesanddisbursements(collectively,“Costs”),incurredinconnectionwithanyclaim,action,suit,proceedingorinvestigation,whethercivil,criminal,administrativeorinvestigative,arisingoutoforpertainingtothefactthattheD&OIndemnifiedPartyisorwasadirectororofficerofOpexaorAcer,whetherassertedorclaimedpriorto,atoraftertheEffectiveTime,tothefullestextentpermittedundertheDGCLorTBOCfordirectorsorofficersofDelawarecorporationsorTexascorporations,asapplicable.EachD&OIndemnifiedPartywillbeentitledtoadvancementofexpensesincurredinthedefenseofanysuchclaim,action,suit,proceedingorinvestigationfromeachofOpexaandtheSurvivingCorporation,jointlyandseverally,uponreceiptbyOpexaortheSurvivingCorporationfromtheD&OIndemnifiedPartyofarequesttherefor;provided, thatanypersontowhomexpensesareadvancedprovidesanundertaking,asapplicable,torepaysuchadvancesifitisultimatelydeterminedthatsuchpersonisnotentitledtoindemnification.

(b) Thecertificateofformation/incorporationandbylawsofeachofOpexaandtheSurvivingCorporationshallcontain,andOpexashallcausethecertificateofincorporationandbylawsoftheSurvivingCorporationtosocontain,provisionsnolessfavorablewithrespecttoindemnification,advancementofexpensesandexculpationofpresentandformerdirectorsandofficersofeachofOpexaandAcerthanarepresentlysetforthinthecertificateofformation/incorporationandbylawsofOpexaandAcer,asapplicable,whichprovisionsshallnotbeamended,modifiedorrepealedforaperiodofsix(6)years’timefromtheEffectiveTimeinamannerthatwouldadverselyaffecttherightsthereunderofindividualswho,atorpriortotheEffectiveTime,wereofficersordirectorsofOpexaorAcer.

(c) PriortotheEffectiveTime,Opexashallpurchase(andfortheavoidanceofdoubt,thefeesandexpensestobepaidbyOpexashallreducetheNetCash)a“tail”insurancepolicywithaneffectivedateasoftheClosingDate,whichshallremaineffectiveforsix(6)yearsfollowingtheClosingDate,atleastthesamecoverageandamountsandcontainingthesametermsandconditionsthatarenotlessfavorabletotheD&OIndemnifiedParties.

(d) Opexashallpayallreasonableexpenses,includingreasonableattorneys’fees,thatmaybeincurredbythepersonsreferredtointhisSection5.7inconnectionwiththeirenforcementoftheirrightsprovidedinthisSection5.7.

(e) TheprovisionsofthisSection5.7areintendedtobeinadditiontotherightsotherwiseavailabletotheD&OIndemnifiedPartiesbylaw,charter,statute,bylaworagreement.TheobligationsofOpexaunderthisSection5.7shallsurvivetheconsummationoftheMergerandshallnotbeterminatedormodifiedinsuchamannerastoadverselyaffectanyIndemnifiedPartytowhomthisSection5.7applieswithouttheconsentofsuchaffectedD&OIndemnifiedParty(itbeingexpresslyagreedthattheD&OIndemnifiedPartiestowhomthis

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Section5.7applies,aswellastheirheirsandrepresentatives,shallbethird-partybeneficiariesofthisSection5.7,eachofwhommayenforcetheprovisionsofthisSection5.7).

(f) IntheeventOpexaortheSurvivingCorporationoranyoftheirrespectivesuccessorsorassigns(i)consolidateswithormergesintoanyotherpersonandshallnotbethecontinuingorsurvivingcorporationorentityofsuchconsolidationormerger,or(ii)transfersallorsubstantiallyallofitspropertiesandassetstoanyperson,then,andineachsuchcase,properprovisionshallbemadesothatthesuccessorsandassignsofOpexaortheSurvivingCorporation,asthecasemaybe,shallsucceedtotheobligationssetforthinthisSection5.7.OpexashallcausetheSurvivingCorporationtoperformalloftheobligationsoftheSurvivingCorporationunderthisSection5.7.

5.8 Additional Agreements .ThePartiesshall(a)usecommerciallyreasonableeffortstocausetobetakenallactionsnecessarytoconsummatetheContemplatedTransactionsand(b)reasonablycooperatewiththeotherPartiesandprovidetheotherPartieswithsuchassistanceasmaybereasonablyrequestedforthepurposeoffacilitatingtheperformancebyeachPartyofitsrespectiveobligationsunderthisAgreementandtoenabletheSurvivingCorporationtocontinuetomeetitsobligationsunderthisAgreementfollowingtheClosing.Withoutlimitingthegeneralityoftheforegoing,eachPartytothisAgreement:(i)shallmakeallfilingsandothersubmissions(ifany)andgiveallnotices(ifany)requiredtobemadeandgivenbysuchPartyinconnectionwiththeContemplatedTransactions;(ii)shallusecommerciallyreasonableeffortstoliftanyinjunctionprohibiting,oranyotherlegalbarto,theContemplatedTransactions;and(iii)shallusecommerciallyreasonableeffortstosatisfytheconditionsprecedenttotheconsummationofthisAgreement.

5.9 Disclosure .WithoutlimitingAcer’sorOpexa’sobligationsundertheConfidentialityAgreement,eachPartyshallnot,andshallnotpermitanyofitsSubsidiariesoranyRepresentativeofsuchPartyto,issueanypressreleaseormakeanydisclosure(toanycustomersoremployeesofsuchParty(otherthanemployeesthathaveabonafideneedtoknow)tothepublicorotherwise)regardingtheContemplatedTransactionsunless:(a)theotherPartyhasapprovedsuchpressreleaseordisclosureinwriting;or(b)suchPartyhasdeterminedingoodfaith,upontheadviceofoutsidelegalcounsel,thatsuchdisclosureisrequiredbyapplicableLegalRequirementsand,totheextentpracticable,beforesuchpressreleaseordisclosureisissuedormade,suchPartyadvisestheotherPartyof,andconsultswiththeotherPartyregarding,thetextofsuchpressreleaseordisclosure.

5.10 Listing .Opexashalluseitscommerciallyreasonableefforts:(a)tomaintainitsexistinglistingontheNASDAQCapitalMarketandtoobtainapprovalofthelistingofthecombinedcompanyontheNASDAQCapitalMarket;(b)toeffecttheNASDAQReverseSplit,(c)withoutderogatingfromthegeneralityoftherequirementsofclause“(a)”andtotheextentrequiredbytherulesandregulationsofNASDAQ,to(i)prepareandsubmittoNASDAQanotificationformforthelistingofthesharesofOpexaCommonStocktobeissuedintheMerger,and(ii)tocausesuchsharestobeapprovedforlisting(subjecttonoticeofissuance);and(d)totheextentrequiredbyNASDAQMarketplaceRule5110,tofileaninitiallistingfortheOpexaCommonStockonNASDAQCapitalMarket(the“NASDAQListingApplication”)andtocausesuchNASDAQListingApplicationtobeapprovedforlisting(subjecttoofficialnoticeofissuance).AcerwillcooperatewithOpexaasreasonablyrequestedbyOpexawith

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respecttotheNASDAQListingApplicationandpromptlyfurnishtoOpexaallinformationconcerningAcerandAcerStockholdersthatmayberequiredorreasonablyrequestedinconnectionwithanyactioncontemplatedbythisSection5.10.

5.11 Tax Matters .

(a) Opexa,MergerSubandAcershallusetheirrespectivecommerciallyreasonableeffortstocausetheMergertoqualify,andagreenotto,andnottopermitorcauseanyaffiliateoranySubsidiaryto,takeanyactionsorcauseanyactiontobetakenwhichwouldreasonablybeexpectedtopreventorimpedetheMergerfromqualifying,asa“reorganization”underSection368(a)oftheCode.

(b) ThisAgreementisintendedtoconstitute,andthePartiesherebyadoptthisAgreementas,a“planofreorganization”withinthemeaningofTreasuryRegulationsSection1.368-2(g).ThePartiesshalltreatandshallnottakeanytaxreportingpositioninconsistentwiththetreatmentoftheMergerasareorganizationwithinthemeaningofSection368(a)oftheCodeforU.S.federal,stateandotherrelevantTaxpurposes,unlessotherwiserequiredpursuanttoa“determination”withinthemeaningofSection1313(a)oftheCode.

(c) AcershalluseitscommerciallyreasonableeffortstodelivertoFoleyandPillsburya“TaxRepresentationLetter,”datedasofthedateofthetaxopinionsreferencedinSection5.1(c)andsignedbyanofficerofAcer,containingrepresentationsofAcer,andOpexashalluseitscommerciallyreasonableeffortstodelivertoFoleyandPillsburya“TaxRepresentationLetter,”datedasofthedateofthetaxopinionsreferencedinSection5.1(c)andsignedbyanofficerofOpexa,containingrepresentationsofOpexa,ineachcaseasshallbereasonablynecessaryorappropriatetoenableFoleyandPillsburytorendertheapplicableopinionsdescribedinSection5.1(c)ofthisAgreement.

5.12 Legends .Opexashallbeentitledtoplaceappropriatelegendsonthebookentriesand/orcertificatesevidencinganysharesofOpexaCommonStocktobereceivedintheMergerbyequityholdersofAcerwhomaybeconsidered“affiliates”ofOpexaforpurposesofRules144and145undertheSecuritiesActreflectingtherestrictionssetforthinRules144and145andtoissueappropriatestoptransferinstructionstothetransferagentforOpexaCommonStock.

5.13 Directors and Officers .PriortotheEffectiveTime,buttobeeffectiveattheEffectiveTime,theOpexaBoardofDirectorsshall(i)setthesizeoftheOpexaBoardofDirectorsatseven(7)membersandelectseven(7)designeesselectedbyAcer(withsuchdesignees,intheaggregate,expectedtosatisfytherequisiteindependencerequirementsfortheOpexaBoardofDirectors,aswellasthesophisticationandindependencerequirementsfortherequiredcommitteesoftheOpexaBoardofDirectors,pursuanttoNASDAQ’slistingstandards),eachtoserveasamemberoftheOpexaBoardofDirectors,(ii)takeallnecessaryactiontoappointeachoftheindividualssetforthonSchedule5.13asofficersofOpexatoholdtheofficessetforthoppositehisorhername,and(iii)appointeachofthedirectorssetforthonSchedule5.13tothecommitteesoftheOpexaBoardofDirectorssetforthoppositehisorhername(withsuchdirectors,intheaggregate,expectedtosatisfythesophisticationandindependencerequirementsfortherequiredcommitteesoftheOpexaBoardofDirectorspursuanttoNASDAQ’slistingstandards).

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5.14 Section 16 Matters .PriortotheEffectiveTime,OpexashalltakeallsuchstepsasmayberequiredtocauseanyacquisitionsofOpexaCommonStockandanyoptionstopurchaseOpexaCommonStockresultingfromtheContemplatedTransactions,byeachindividualwhoisreasonablyexpectedtobecomesubjecttothereportingrequirementsofSection16(a)oftheExchangeActwithrespecttoOpexa,tobeexemptunderRule16b-3promulgatedundertheExchangeAct.

5.15 Takeover Statutes .Ifany“controlshareacquisition”,“fairprice”,“moratorium”orotheranti-takeoverLegalRequirementbecomesorisdeemedtobeapplicabletoOpexa,Acer,MergerSub,ortheContemplatedTransactions,theneachofOpexa,Acer,MergerSub,andtheirrespectiveboardofdirectorsshallgrantsuchapprovalsandtakesuchactionsasarenecessarysothattheContemplatedTransactionsmaybeconsummatedaspromptlyaspracticableonthetermscontemplatedherebyandotherwiseacttorendersuchanti-takeoverLegalRequirementinapplicabletotheforegoing.

5.16 Preferred Stock . AcershalltakeallactionnecessarytoeffecttheconversionofAcerPreferredStockintoAcerCommonStockpriortotheEffectiveTime(the“PreferredStockConversion”).

5.17 Termination of Certain Agreements and Rights . Acershallusecommerciallyreasonableeffortstoterminate,atorpriortotheEffectiveTime,thoseagreementssetforthonSchedule5.17(collectively,the“InvestorAgreements”).

5.18 Net Cash .OpexashallusecommerciallyreasonableeffortstoensurethatNetCash(asdeterminedpursuanttoSection1.6)isgreaterthanorequaltonegativeOneMillionandTwoHundredandFiftyThousandDollars(-$1,250,000)asoftheEffectiveTime.

ARTICLE 6

CONDITIONS PRECEDENT TO OBLIGATIONS OF EACH PARTY

TheobligationsofeachPartytoeffecttheMergerandotherwiseconsummatethetransactionstobeconsummatedattheClosingaresubjecttothesatisfactionor,totheextentpermittedbyapplicableLegalRequirements,thewrittenwaiverbyeachoftheParties,atorpriortotheClosing,ofeachofthefollowingconditions:

6.1 Effectiveness of Registration Statement .TheFormS-4RegistrationStatementhasbeendeclaredeffectivebytheSECundertheSecuritiesActandnostopordersuspendingtheeffectivenessoftheFormS-4RegistrationStatementhasbeenissuedbytheSECandnoproceedingsforthatpurposeandnosimilarproceedinghasbeeninitiatedor,totheKnowledgeofOpexa,threatenedbytheSEC.

6.2 No Restraints .(a)Notemporaryrestrainingorder,preliminaryorpermanentinjunctionorotherorderpreventingtheconsummationoftheMergerhasbeenissuedbyanycourtofcompetentjurisdictionorotherGovernmentalBodyofcompetentjurisdictionandremainineffect,andthereshallnotbeanyLegalRequirementwhichhastheeffectofmakingtheconsummationoftheMergeroranyoftheContemplatedTransactionsillegal;and(b)thereshallbenoLegalProceedingpending,orovertlythreatenedinwriting,byanofficialofa

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GovernmentalBodyinwhichsuchGovernmentalBodyindicatesthatitintendstoconductanyLegalProceedingortakeanyotheractionchallengingorseekingtorestrainorprohibittheconsummationoftheMergeroranyoftheContemplatedTransactions.

6.3 Stockholder Approval .(a)AcerhasobtainedtheRequiredAcerStockholderVote,(b)OpexahasobtainedtheRequiredOpexaShareholderVote,and(c)Acerhasreceivedevidence,informandsubstancesatisfactorytoit,thatMergerSubhasobtainedtheRequiredMergerSubStockholderVote.

6.4 Regulatory Matters .AnywaitingperiodapplicabletotheconsummationoftheMergerundertheHSRActorapplicabletoforeignLegalRequirementsrelatingtoantitrustorcompetitionmattershasexpiredorbeenterminated,andthereshallnotbeineffectanyvoluntaryagreementbetweenOpexa,MergerSuband/orAcer,ontheonehand,andtheFederalTradeCommission,theDepartmentofJusticeoranyforeignGovernmentalBody,ontheotherhand,pursuanttowhichsuchPartyhasagreednottoconsummatetheMergerforanyperiodoftime;provided ,thatneitherAcer,ontheonehand,norOpexaorMergerSub,ontheotherhand,shallenterintoanysuchvoluntaryagreementwithoutthewrittenconsentofallParties.

6.5 Listing . (a)TheexistingsharesofOpexaCommonStockhavebeencontinuallylistedonTheNASDAQCapitalMarketasofandfromthedateofthisAgreementthroughtheClosingDate,(b)thesharesofOpexaCommonStocktobeissuedintheMergershallbeapprovedforlisting(subjecttoofficialnoticeofissuance)onTheNASDAQCapitalMarketasoftheEffectiveTime,and(c)totheextentrequiredbyNASDAQMarketplaceRule5110,theNASDAQListingApplicationhasbeenapprovedforlisting(subjecttoofficialnoticeofissuance).

6.6 Net Cash Calculation .OpexaandAcerhaveagreedinwritingupontheNetCashCalculation,ortheAccountingFirmhasdelivereditsdeterminationwithrespecttotheNetCashCalculation,ineachcasepursuanttoSection1.6.

ARTICLE 7

ADDITIONAL CONDITIONS PRECEDENT TO OBLIGATIONS OF OPEXA AND MERGER SUB

TheobligationsofOpexaandMergerSubtoeffecttheMergerandotherwiseconsummatethetransactionstobeconsummatedattheClosingaresubjecttothesatisfactionorthewrittenwaiverbyOpexa,atorpriortotheClosing,ofeachofthefollowingconditions:

7.1 Accuracy of Representations .(a)TherepresentationsandwarrantiesofAcerinSection2.1(Subsidiaries;DueOrganization;OrganizationalDocuments),Section2.2(Authority;VoteRequired),Section2.4(a),Section2.4(b),andSection2.4(c)(Capitalization),aretrueandcorrectinallbutdeminimisrespectsasofthedateofthisAgreementandaretrueandcorrectinallbutdeminimisrespectsonandasoftheClosingDatewiththesameforceandeffectasifmadeontheClosingDate,exceptforthoserepresentationsandwarrantieswhichaddressmattersonlyasofaparticulardate(whichrepresentationsweresotrueandcorrectasofsuchparticulardate);and(b)allotherrepresentationsandwarrantiesofAcerinArticle2ofthisAgreementare

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trueandcorrectasofthedateofthisAgreementandaretrueandcorrectonandasoftheClosingDatewiththesameforceandeffectasifmadeontheClosingDateexcept(withrespectsolelytothisclause(b))(i)ineachcase,orintheaggregate,wherethefailuretobetrueandcorrectwouldnothaveanAcerMaterialAdverseEffect(providedthatall“AcerMaterialAdverseEffect”qualificationsandothermaterialityqualificationslimitingthescopeoftherepresentationsandwarrantiesofAcerinArticle2ofthisAgreementwillbedisregarded),or(ii)forthoserepresentationsandwarrantieswhichaddressmattersonlyasofaparticulardate(whichrepresentationsweresotrueandcorrect,subjecttothequalificationsassetforthintheprecedingclause(i),asofsuchparticulardate).

7.2 Performance of Covenants .EachofthecovenantsandobligationsinthisAgreementthatAcerisrequiredtocomplywithortoperformatorpriortotheClosinghavebeencompliedwithandperformedbyAcerinallmaterialrespects.

7.3 No Acer Material Adverse Effect .SincethedateofthisAgreement,therehasnotoccurredanyAcerMaterialAdverseEffectthatiscontinuing.

7.4 Preferred Stock Conversion .AcerhaseffectedthePreferredStockConversion.

7.5 Termination of Investor Agreements . TheInvestorAgreementshavebeenterminated.

7.6 Acer Debt Conversion ; No Debt. AcerhaseffectedaconversionofalloutstandingconvertibledebtintosharesofAcerCommonStock,andattheClosingAcershallhavenoindebtednessforborrowedmoneyoutstanding.

7.7 Acer Pre-Closing Financing . TheAcerPre-ClosingFinancingshallhavebeenconsummatedandAcershallhavereceivedtheproceedsoftheAcerPre-ClosingFinancingonthetermsandconditionssetforthintheSubscriptionAgreement.

7.8 Documents . Opexahasreceivedthefollowingdocuments,eachofwhichshallbeinfullforceandeffectasoftheClosingDate:

(a) acertificateexecutedbytheChiefExecutiveOfficerandChiefFinancialOfficerofAcerconfirmingthattheconditionssetforthinSections7.1,7.2,7.3,7.4,7.5,7.6and7.7havebeendulysatisfied;

(b) (i)certificatesofgoodstandingofAcerinitsjurisdictionoforganizationandthevariousforeignjurisdictionsinwhichitisqualifiedtodobusiness,(ii)certifiedcopiesofthecertificateofincorporationandbylawsofAcer,and(iii)acertificateastotheincumbencyoftheChiefExecutiveOfficerandChiefFinancialOfficerofAcerandastotheadoptionofresolutionsoftheAcerBoardofDirectorsauthorizingtheexecutionofthisAgreementandtheconsummationoftheContemplatedTransactionstobeperformedbyAcerhereunder;

(c) aformofnoticetotheInternalRevenueServiceinaccordancewiththerequirementsofTreasuryRegulationSection1.897-2(h)andinformandsubstancereasonablyacceptabletoOpexaalongwithwrittenauthorizationforOpexatodeliversuchnoticeformtotheInternalRevenueServiceonbehalfofAcerupontheClosing;and

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(d) theAllocationCertificate.

ARTICLE 8

ADDITIONAL CONDITIONS PRECEDENT TO OBLIGATIONS OF ACER

TheobligationsofAcertoeffecttheMergerandotherwiseconsummatethetransactionstobeconsummatedattheClosingaresubjecttothesatisfactionorthewrittenwavierbyAcer,atorpriortotheClosing,ofeachofthefollowingconditions:

8.1 Accuracy of Representations .(a)TherepresentationsandwarrantiesofOpexaandMergerSubinSection3.1(Subsidiaries;DueOrganization;OrganizationalDocuments),Section3.2(Authority;VoteRequired),Section3.4(a),Section3.4(b),Section3.4(c),Section3.4(e)(Capitalization),aretrueandcorrectinallbutdeminimisrespectsasofthedateofthisAgreementandaretrueandcorrectinallbutdeminimisrespectsonandasoftheClosingDatewiththesameforceandeffectasifmadeontheClosingDate,exceptforthoserepresentationsandwarrantieswhichaddressmattersonlyasofaparticulardate(whichrepresentationsweresotrueandcorrectasofsuchparticulardate);and(b)allotherrepresentationsandwarrantiesofOpexaandMergerSubinArticle3ofthisAgreementaretrueandcorrectasofthedateofthisAgreementandaretrueandcorrectonandasoftheClosingDatewiththesameforceandeffectasifmadeontheClosingDateexcept(withrespectsolelytothisclause(b))(i)ineachcase,orintheaggregate,wherethefailuretobetrueandcorrectwouldnothaveanOpexaMaterialAdverseEffect(providedthatall“OpexaMaterialAdverseEffect”qualificationsandothermaterialityqualificationslimitingthescopeoftherepresentationsandwarrantiesofOpexainArticle3ofthisAgreementwillbedisregarded),or(ii)forthoserepresentationsandwarrantieswhichaddressmattersonlyasofaparticulardate(whichrepresentationsweresotrueandcorrect,subjecttothequalificationsassetforthintheprecedingclause(i),asofsuchparticulardate).

8.2 Performance of Covenants .(a)OpexaandMergerSubwillhavecompliedwiththecovenantsandobligationssetforthinSection4.2(b)(ii),Section4.2(b)(xii),andSection5.6inallrespectsand(b)alloftheothercovenantsandobligationsinthisAgreementthateitherOpexaorMergerSubisrequiredtocomplywithortoperformatorpriortotheClosinghavebeencompliedwithandperformedinallmaterialrespects.

8.3 No Opexa Material Adverse Effect .SincethedateofthisAgreement,therehasnotoccurredanyOpexaMaterialAdverseEffectthatiscontinuing.

8.4 Termination of Contracts .Acerhasreceivedevidence,informandsubstancesatisfactorytoit,thatallOpexaContracts(otherthantheOpexaContractslistedonSchedule8.4)havebeen(a)terminated,assigned,orfullyperformedbyOpexaand(b)allobligationsofOpexathereunderhavebeenfullysatisfied,waivedorotherwisedischarged.

8.5 Board of Directors and Officers .OpexahascausedtheOpexaBoardofDirectorsandtheofficersofOpexa,tobeconstitutedassetforthinSection5.13ofthisAgreementeffectiveasoftheEffectiveTime.

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8.6 Sarbanes-Oxley Certifications .NeithertheprincipalexecutiveofficernortheprincipalfinancialofficerofOpexahasfailedtoprovide,withrespecttoanyOpexaSECDocumentfiled(orrequiredtobefiled)withtheSEConorafterthedateofthisAgreement,anynecessarycertificationintheformrequiredunderRule13a-14undertheExchangeActand18U.S.C.§1350.

8.7 Net Cash Threshold .NetCashisgreaterthanorequaltonegativeOneMillionandTwoHundredandFiftyThousandDollars(-$1,250,000).

8.8 Shell Company Status .OpexaisnotanissueridentifiedinRule144(i)(1)(i)oftheSecuritiesActorashellcompanyasdefinedinRule12b-2oftheExchangeAct.

8.9 Satisfaction of Liabilities .OpexahassatisfiedallofitsLiabilitieswithrespecttoindebtednessastoborrowedmoneyasoftheClosingDateandAcerhasreceivedpayofflettersorotherproofofpaymentevidencingthesatisfactionofsuchLiabilitiesandreleaseofanyEncumbrancesrelatedtosuchLiabilities,informandsubstancesatisfactory,toAcer.

8.10 Amendment to Certificate of Formation .IfrequestedbyAcer,Opexahasprovidedfile-stampedcopiesoftheamendmenttoOpexa’scertificateofformationevidencingtheNASDAQReverseSplit.

8.11 Bylaws .TheOpexaBoardofDirectorshasapprovedanamendmenttothebylawsofOpexatochangethenameofOpexato“AcerTherapeuticsInc.”.

8.12 Documents .Acerhasreceivedthefollowingdocuments,eachofwhichshallbeinfullforceandeffectasoftheClosingDate:

(a) acertificateexecutedbytheChiefExecutiveOfficerandActingChiefFinancialOfficerofOpexaconfirmingthattheconditionssetforthinSections8.1,8.2,8.3,8.5,8.6,8.7,8.8,8.9,8.10and8.11havebeendulysatisfied;

(b) (i)certificatesofgoodstandingofeachofOpexaandMergerSubinitsjurisdictionoforganizationandthevariousforeignjurisdictionsinwhicheachisqualifiedtodobusiness,(ii)certifiedcopiesofthecertificateofformation/incorporationandbylawsofOpexaandMergerSub,and(iii)acertificateastotheincumbencyoftheofficersofOpexaandMergerSubandastotheadoptionofresolutionsoftheOpexaBoardofDirectorsandtheboardofdirectorsofMergerSubauthorizingtheexecutionofthisAgreementandtheconsummationoftheContemplatedTransactionstobeperformedbyOpexaandMergerSubhereunder;

(c) writtenresignationsinformssatisfactorytoAcer,datedasoftheClosingDateandeffectiveasoftheClosingexecutedbyallofficersanddirectorsofOpexa(and,ifapplicable,removalofsuchpersonsasauthorizedpartiestodrawonormakewithdrawalsfromOpexa’saccounts);and

(d) theOpexaOutstandingSharesCertificate.

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ARTICLE 9

TERMINATION

9.1 Termination .ThisAgreementmaybeterminatedpriortotheEffectiveTime(whetherbeforeorafterobtainingtheRequiredAcerStockholderVoteorRequiredOpexaShareholderVote,asapplicable,unlessotherwisespecifiedbelow):

(a) bymutualwrittenconsentdulyauthorizedbytheBoardsofDirectorsofOpexaandAcer;

(b) byeitherOpexaorAceriftheMergershallnothavebeenconsummatedbyDecember30,2017(the“OutsideDate”);provided ,however ,thattherighttoterminatethisAgreementunderthisSection9.1(b)shallnotbeavailabletoAcer,ontheonehand,ortoOpexa,ontheotherhand,ifsuchParty’s(or,inthecaseofOpexa,MergerSub’s)actionorfailuretoacthasbeenaprincipalcauseofthefailureoftheMergertooccuronorbeforetheOutsideDateandsuchactionorfailuretoactconstitutesabreachofthisAgreement;provided ,further ,that,intheeventthattheSEChasnotdeclaredeffectiveundertheSecuritiesActtheFormS-4RegistrationStatementbythedatewhichissixty(60)calendardayspriortotheOutsideDate,theneitherAcerorOpexashallbeentitled,bynoticedeliveredtotheotherParty,toextendtheOutsideDateforanadditionalsixty(60)calendardays;

(c) byeitherOpexaorAcerifacourtofcompetentjurisdictionorotherGovernmentalBodyhasissuedafinalandnonappealableorder,decreeorruling,orhastakenanyotheraction,havingtheeffectofpermanentlyrestraining,enjoiningorotherwiseprohibitingtheMerger;provided ,however ,thattherighttoterminatethisAgreementunderthisSection9.1(c)shallnotbeavailabletoAcer,ontheonehand,ortoOpexa,ontheotherhand,ifsuchParty’s(or,inthecaseofOpexa,MergerSub’s)actionorfailuretoacthasbeenaprincipalcauseofsuchissuanceoractionbyaGovernmentalBody,andsuchactionorfailuretoactconstitutesabreachofthisAgreement;

(d) byOpexaiftheRequiredAcerStockholderVoteshallnothavebeenobtainedwithinfive(5)BusinessDaysoftheFormS-4RegistrationStatementbeingdeclaredeffectivebytheSEC;provided ,however ,thatoncetheRequiredAcerStockholderVotehasbeenobtained,OpexamaynotterminatethisAgreementpursuanttothisSection9.1(d);

(e) byeitherOpexaorAcerif(i)theOpexaShareholders’Meeting(includinganyadjournmentsandpostponementsthereof)hasbeenheldandcompletedandtheOpexaShareholdershavetakenafinalvoteontheOpexaShareholderMattersand(ii)theOpexaShareholderMattershavenotbeenapprovedattheOpexaShareholders’Meeting(oranyadjournmentorpostponementthereof)bytheRequiredOpexaShareholderVote;provided ,however ,thattherighttoterminatethisAgreementunderthisSection9.1(e)shallnotbeavailabletoOpexawherethefailuretoobtaintheRequiredOpexaShareholderVotehasbeencausedbytheactionorfailuretoactofOpexaorMergerSubandsuchactionorfailuretoactconstitutesamaterialbreachbyOpexaorMergerSubofthisAgreement;

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(f) byAcer(atanytimepriortoobtainingtheRequiredOpexaShareholderVote)ifanyofthefollowingeventshaveoccurred:(i)OpexafailedtoincludetheOpexaBoardRecommendationintheProxyStatement/Prospectus/InformationStatement;(ii)theOpexaBoardofDirectorshasapproved,endorsedorrecommendedanyAcquisitionProposal;(iii)OpexahasfailedtoholdtheOpexaShareholders’Meetingwithinsixty(60)calendardaysaftertheFormS-4RegistrationStatementbeingdeclaredeffectivebytheSECundertheSecuritiesAct(otherthantotheextentthattheFormS-4RegistrationStatementissubjecttoanystoporderorproceeding(orthreatenedproceedingbytheSEC)seekingastoporderwithrespecttotheFormS-4RegistrationStatement,inwhichcasesuchsixty(60)-calendardayperiodshallbetolledfortheearlierofsixty(60)calendardaysorsolongassuchstoporderremainsineffectorsuchproceedingorthreatenedproceedingremainspending);(iv)OpexahasenteredintoanyAcquisitionAgreement(otherthanaconfidentialityagreementpermittedpursuanttoSection4.5);or(v)OpexaoranyofitsRepresentativeshaswillfullyandintentionallybreachedtheprovisionssetforthinSection4.5;

(g) byOpexa(atanytimepriortotheapprovaloftheMergerbytheRequiredAcerStockholderVote)ifanyofthefollowingeventshaveoccurred:(i)theAcerBoardofDirectorsfailedtoincludetheAcerBoardRecommendationintheProxyStatement/Prospectus/InformationStatement;(ii)theAcerBoardofDirectorshasapproved,endorsedorrecommendedanyAcquisitionProposal;(iii)AcerhasenteredintoanyAcquisitionAgreement(otherthanaconfidentialityagreementpermittedpursuanttoSection4.5);or(iv)AceroranyofitsRepresentativeshaswillfullyandintentionallybreachedtheprovisionssetforthinSection4.5oftheAgreement;

(h) byAcer,uponabreachofanyrepresentation,warranty,covenantoragreementonthepartofOpexaorMergerSubsetforthinthisAgreement,orifanyrepresentationorwarrantyofOpexaorMergerSubhasbecomeinaccurate,ineithercasesuchthattheconditionssetforthinSection8.1orSection8.2wouldnotbesatisfied;provided, however ,thatifsuchinaccuracyinOpexa’sorMergerSub’srepresentationsandwarrantiesorbreachbyOpexaorMergerSubiscurablebyOpexaorMergerSub,thenthisAgreementshallnotterminatepursuanttothisSection9.1(h)asaresultofsuchparticularbreachorinaccuracyunlesssuchbreachremainsuncuredfifteen(15)calendardaysfollowingthedateofwrittennoticefromAcertoOpexaofsuchbreachorinaccuracyanditsintentiontoterminatepursuanttothisSection9.1(h);provided further, however ,thatnoterminationmaybemadepursuanttothisSection9.1(h)solelyasaresultofthefailuretoobtaintheRequiredOpexaShareholderVoteiftheOpexaShareholders’Meetinghasbeenheldandcompleted(inwhichcase,terminationmustbemadepursuanttoSection9.1(e));

(i) byOpexa,uponabreachofanyrepresentation,warranty,covenantoragreementonthepartofAcersetforthinthisAgreement,orifanyrepresentationorwarrantyofAcerhasbecomeinaccurate,ineithercasesuchthattheconditionssetforthinSection7.1orSection7.2wouldnotbesatisfied;provided, however ,thatifsuchinaccuracyinAcer’srepresentationsandwarrantiesorbreachbyAceriscurablebyAcer,thenthisAgreementshallnotterminatepursuanttothisSection9.1(i)asaresultofsuchparticularbreachorinaccuracyunlesssuchbreachremainsuncuredfifteen(15)calendardaysfollowingthedateofwrittennoticefromOpexatoAcerofsuchbreachorinaccuracyanditsintentiontoterminatepursuanttothisSection9.1(i);provided further, however ,thatnoterminationmaybemadepursuanttothis

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Section9.1(i)solelyasaresultofthefailuretoobtaintheRequiredAcerStockholderVote(inwhichcase,terminationmustbemadepursuanttoSection9.1(d));

(j) byOpexa,atanytime,if(i)allconditionsinSections6and8havebeensatisfied(otherthanthoseconditionsthatbytheirnaturearetobesatisfiedbyactionstakenattheClosing),andremainsosatisfiedand(ii)OpexairrevocablyconfirmsbywrittennoticetoAcerthat(A)eachoftheconditionsinSection7(otherthantheconditionsetforthinSection7.7(AcerPre-ClosingFinancing)andthoseconditionsthatbytheirnaturearetobesatisfiedbyactionstakenattheClosing)hasbeensatisfiedorthatOpexaiswillingtowaiveanysuchconditionsthathavenotbeensatisfied(otherthantheconditionsetforthinSection7.7)and(B)itispreparedtoconsummatetheClosinguponsatisfactionoftheconditionsetforthinSection7.7(i.e.,consummationoftheAcerPre-ClosingFinancing);provided ,thatOpexashallnotterminatethisAgreementpursuanttothisSection9.1(j)(x)unlesstheconditionsetforthinSection7.7hasnotbeensatisfiedwithinfive(5)calendardaysafterdeliveryofthewrittennoticefromOpexatoAcerpursuanttoclause(ii)ofthisSection9.1(j)and(y)totheextentthatAcerisactivelydisputingthroughaLegalProceedingtheunderlyingreason(s)forthefailureoftheconsummationoftheAcerPre-ClosingFinancingwithoneormorePurchasers(asdefinedintheSubscriptionAgreement)partytotheSubscriptionAgreementandsuchPurchasers,togetherwithallotherPurchaserswhichremaincommittedtoproceedwiththeAcerPre-ClosingFinancingpursuanttotheSubscriptionAgreement,representatleasttherequisiteparticipationtosatisfytheminimumamountcontemplatedbytheAcerPre-ClosingFinancing;or

(k) byAcerifanyofthefollowingeventshaveoccurred:(i)theexistingsharesofOpexaCommonStockceasetobelistedonTheNASDAQCapitalMarket,(ii)NASDAQinformsOpexathatitwillnotapprovethesharesofOpexaCommonStocktobeissuedintheMergerforlistingonTheNASDAQCapitalMarketasoftheEffectiveTime(whetherornotsuchdecisionissubjecttoappeal),or(iii)NASDAQinformsOpexathattheNASDAQListingApplicationisnot,orwillnotbe,approvedforlisting(whetherornotsuchdecisionissubjecttoappeal),onlytotheextentthatsuchNASDAQListingApplicationisrequiredbyNASDAQMarketplaceRule5110;provided ,however ,thattheforegoingclauses(ii)and(iii)aresubjecttoacureperiodoften(10)BusinessDaysifrequestedbyOpexa.

9.2 Effect of Termination .ThePartydesiringtoterminatethisAgreementpursuanttoSection9.1(otherthanpursuanttoSection9.1(a))shallgiveawrittennoticeofsuchterminationtotheotherPartyspecifyingtheprovisionshereofpursuanttowhichsuchterminationismadeandthebasistherefordescribedinreasonabledetail.IntheeventoftheterminationofthisAgreementasprovidedinSection9.1,thisAgreementshallbeofnofurtherforceoreffect;provided ,however ,that(i)Section5.9,thisSection9.2,Section9.3,andArticle10shallsurvivetheterminationofthisAgreementandshallremaininfullforceandeffect,and(ii)theterminationofthisAgreementshallnotrelieveanyPartyforitsfraudorfromanyliabilityforanywillfulandmaterialbreachofanyrepresentation,warranty,covenant,obligationorotherprovisioncontainedinthisAgreement.

9.3 Expenses; Termination Fees .

(a) ExceptassetforthinthisSection9.3,allfeesandexpensesincurredinconnectionwiththisAgreementandtheContemplatedTransactionsshallbepaidbytheParty

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incurringsuchexpenses,whetherornottheMergerisconsummated;provided ,however ,thatOpexaandAcershallshareequallyallfeesandexpenses,otherthanattorneys’andaccountants’feesandexpenses,incurredinrelationtothefilingsbythePartiesunderanyfilingrequirementundertheHSRActandanyforeignantitrustLegalRequirementapplicabletothisAgreementandtheContemplatedTransactions;provided ,further, thatOpexaandAcershallalsoshareequallyallfeesandexpenses(i)incurredinrelationtothefilingoftheNASDAQListingApplicationwithNASDAQ,(ii)byengagementoftheExchangeAgentand(iii)inrelationtotheprinting(e.g. ,paidtoafinancialprinter)andfilingwiththeSECoftheFormS-4RegistrationStatement(includinganyfinancialstatementsandexhibits)andanyamendmentsorsupplementsthereto.

(b) (i) If(A)thisAgreementisterminatedbyOpexaorAcerpursuanttoSection9.1(e)orbyAcerpursuanttoSection9.1(f),(B)atanytimebeforethedateofterminationanAcquisitionProposalwithrespecttoOpexahasbeenpubliclyannouncedordisclosedorotherwisecommunicatedbytheOpexaBoardofDirectorstotheOpexaShareholders,and(C)intheeventthisAgreementisterminatedpursuanttoSection9.1(e),withintwelve(12)monthsafterthedateofsuchtermination,OpexaentersintoadefinitiveagreementwithrespecttoaSubsequentTransactionorconsummatesaSubsequentTransaction,thenOpexashallpaytoAcer,withinten(10)BusinessDaysaftertermination(or,ifapplicable,upontheearlierofsuchentryintoadefinitiveagreementwithrespecttoaSubsequentTransactionorconsummationofaSubsequentTransaction),anonrefundablefeeinanamountequalto$250,000(the“AcerTerminationFee”),inadditiontoanyamountpayabletoAcerpursuanttoSection9.3(e).

(ii) If(A)thisAgreementisterminatedbyOpexapursuanttoSection9.1(d)orSection9.1(g),(B)atanytimebeforeobtainingtheRequiredAcerStockholderVoteanAcquisitionProposalwithrespecttoAcerhasbeenpubliclyannounced,disclosedorotherwisecommunicatedbytheAcerBoardofDirectorstotheAcerStockholders,and(C)intheeventthisAgreementisterminatedpursuantSection9.1(d),withintwelve(12)monthsafterthedateofsuchtermination,AcerentersintoadefinitiveagreementwithrespecttoaSubsequentTransactionorconsummatesaSubsequentTransaction,thenAcershallpaytoOpexa,withinten(10)BusinessDaysaftertermination(or,ifapplicable,upontheearlierofsuchentryintoadefinitiveagreementwithrespecttoaSubsequentTransactionorconsummationofaSubsequentTransaction),anonrefundablefeeinanamountequalto$1,000,000(the“OpexaTerminationFee”),inadditiontoanyamountpayabletoOpexapursuanttoSection9.3(e).

(iii) IfthisAgreementisterminatedbyOpexapursuanttoSection9.1(j),then,withintwo(2)BusinessDaysaftersuchtermination,AcershallpaytoOpexatheOpexaTerminationFee,inadditiontoanyamountpayabletoOpexapursuanttoSection9.3(e).

(c) (i)IfthisAgreementisterminatedbyAcerpursuanttoSection9.1(h)or(ii)intheeventofafailureofAcertoconsummatethetransactionstobeconsummatedattheClosingsolelyasaresultofanOpexaMaterialAdverseEffectassetforthinSection8.3(provided ,that,withrespecttothisclause(ii)only,atsuchtimealloftheotherconditionsprecedenttoOpexa’sobligationtoclosesetforthinArticle6andArticle7ofthisAgreementhavebeensatisfiedbyAcer,arecapableofbeingsatisfiedbyAcerorhavebeenwaivedbyOpexa),thenOpexashallreimburseAcerforallreasonablefeesandexpensesincurredbyAcer

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inconnectionwiththisAgreementandthetransactionscontemplatedhereby,including(A)allfeesandexpensesincurredinconnectionwiththepreparation,printingandfiling,asapplicable,oftheFormS-4RegistrationStatement(includinganypreliminarymaterialsrelatedtheretoandallamendmentsandsupplementsthereto,aswellasanyfinancialstatementsandschedulesthereto)and(B)allfeesandexpensesincurredinconnectionwiththepreparationandfilingunderanyfilingrequirementofanyGovernmentalBodyapplicabletothisAgreementandthetransactionscontemplatedhereby(suchexpenses,including(A)and(B)above,collectively,the“Third-PartyExpenses”),uptoamaximumof$200,000,bywiretransferofsame-dayfundswithinten(10)BusinessDaysfollowingthedateonwhichAcersubmitstoOpexatrueandcorrectcopiesofreasonabledocumentationsupportingsuchThird-PartyExpenses;provided ,however ,thatsuchThird-PartyExpensesshallnotincludeanyamountsforafinancialadvisortoAcerexceptforreasonablydocumentedout-of-pocketexpensesotherwisereimbursablebyAcertosuchfinancialadvisorpursuanttothetermsofAcer’sengagementletterorsimilararrangementwithfinancialadvisor.

(d) (i)IfthisAgreementisterminatedbyOpexapursuanttoSection9.1(i)or(ii)intheeventofafailureofOpexatoconsummatethetransactionstobeconsummatedattheClosingsolelyasaresultofanAcerMaterialAdverseEffectassetforthinSection7.3(provided ,that,withrespecttothisclause(ii)only,atsuchtimealloftheotherconditionsprecedenttoAcer’sobligationtoclosesetforthinArticle6andArticle8ofthisAgreementhavebeensatisfiedbyOpexa,arecapableofbeingsatisfiedbyOpexaorhavebeenwaivedbyAcer),thenAcershallreimburseOpexaforallThird-PartyExpensesincurredbyOpexauptoamaximumof$200,000,bywiretransferofsame-dayfundswithinten(10)BusinessDaysfollowingthedateonwhichOpexasubmitstoAcertrueandcorrectcopiesofreasonabledocumentationsupportingsuchThird-PartyExpenses;provided ,however ,thatsuchThird-PartyExpensesshallnotincludeanyamountsforafinancialadvisortoOpexaexceptforreasonablydocumentedout-of-pocketexpensesotherwisereimbursablebyOpexatosuchfinancialadvisorpursuanttothetermsofOpexa’sengagementletterorsimilararrangementwithfinancialadvisor.

(e) IfeitherPartyfailstopaywhendueanyamountpayablebysuchPartyunderSection9.3(b),Section9.3(c),orSection9.3(d),then(i)suchPartyshallreimbursetheotherPartyforreasonablecostsandexpenses(includingreasonablefeesanddisbursementsofcounsel)incurredinconnectionwiththecollectionofsuchoverdueamountandtheenforcementbytheotherPartyofitsrightsunderthisSection9.3,and(ii)suchPartyshallpaytotheotherPartyinterestonsuchoverdueamount(fortheperiodcommencingasofthedatesuchoverdueamountwasoriginallyrequiredtobepaidandendingonthedatesuchoverdueamountisactuallypaidtotheotherPartyinfull)atarateperannumequaltothe“primerate”(asannouncedbyBankofAmericaoranysuccessorthereto)ineffectonthedatesuchoverdueamountwasoriginallyrequiredtobepaid.

ThePartiesagreethatthepaymentofthefeesandexpensessetforthinthisSection9.3,subjecttoSection9.2,shallbethesoleandexclusiveremedyofeachPartyfollowingaterminationofthisAgreementunderthecircumstancesdescribedinthisSection9.3,itbeingunderstoodthatinnoeventshalleitherOpexaorAcerberequiredtopayfeesordamagespayablepursuanttothisSection9.3onmorethanoneoccasion.SubjecttoSection9.2,thepaymentofthefeesandexpensessetforthinthisSection9.3,andtheprovisionsofSection

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10.10,eachofthePartiesandtheirrespectiveAffiliateswillnothaveanyliability,willnotbeentitledtobringormaintainanyotherclaim,actionorproceedingagainsttheother,shallbeprecludedfromanyotherremedyagainsttheother,atlaworinequityorotherwise,andshallnotseektoobtainanyrecovery,judgmentordamagesofanykindagainsttheother(oranypartner,member,shareholder,stockholder,director,officer,employee,Subsidiary,affiliate,agentorotherrepresentativeofsuchParty)inconnectionwithorarisingoutoftheterminationofthisAgreement,anybreachbyanyPartygivingrisetosuchterminationorthefailureoftheContemplatedTransactionstobeconsummated.EachofthePartiesacknowledgesthat(i)theagreementscontainedinthisSection9.3,areanintegralpartoftheContemplatedTransactions,(ii)withouttheseagreements,thePartieswouldnotenterintothisAgreementand(iii)anyamountpayablepursuanttothisSection9.3,isnotapenalty,butratherisliquidateddamagesinareasonableamountthatwillcompensatethePartiesinthecircumstancesinwhichsuchamountispayable.

ARTICLE 10

MISCELLANEOUS PROVISIONS

10.1 Non-Survival of Representations and Warranties .TherepresentationsandwarrantiesofAcer,MergerSubandOpexacontainedinthisAgreementoranycertificateorinstrumentdeliveredpursuanttothisAgreementshallterminateattheEffectiveTime,andonlythecovenantsthatbytheirtermssurvivetheEffectiveTimeandthisSection10.1shallsurvivetheEffectiveTime.

10.2 Amendment .ThisAgreementmaybeamendedwiththeapprovaloftherespectiveBoardsofDirectorsofAcer,MergerSubandOpexaatanytime(whetherbeforeorafterobtainingtheRequiredOpexaShareholderVoteortheRequiredAcerStockholderVote);provided ,however ,thatafteranysuchadoptionandapprovalofthisAgreementbyaParty’sshareholders/stockholders,noamendmentshallbemade,whichbyapplicableLegalRequirementrequiresfurtherapprovaloftheshareholders/stockholdersofsuchParty,withoutthefurtherapprovalofsuchshareholders/stockholders.ThisAgreementmaynotbeamendedexceptbyaninstrumentinwritingsignedonbehalfofeachofAcer,MergerSubandOpexa.

10.3 Waiver .

(a) NofailureonthepartofanyPartytoexerciseanypower,right,privilegeorremedyunderthisAgreement,andnodelayonthepartofanyPartyinexercisinganypower,right,privilegeorremedyunderthisAgreement,shalloperateasawaiverofsuchpower,right,privilegeorremedy;andnosingleorpartialexerciseofanysuchpower,right,privilegeorremedyshallprecludeanyotherorfurtherexercisethereoforofanyotherpower,right,privilegeorremedy.

(b) NoPartyshallbedeemedtohavewaivedanyclaimarisingoutofthisAgreement,oranypower,right,privilegeorremedyunderthisAgreement,unlessthewaiverofsuchclaim,power,right,privilegeorremedyisexpresslysetforthinawritteninstrumentdulyexecutedanddeliveredonbehalfofsuchParty;andanysuchwaivershallnotbeapplicableorhaveanyeffectexceptinthespecificinstanceinwhichitisgiven.

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10.4 Entire Agreement; Counterparts; Exchanges by Facsimile .ThisAgreementandtheotheragreementsreferredtointhisAgreementconstitutetheentireagreementandsupersedeallprioragreementsandunderstandings,bothwrittenandoral,amongorbetweenanyofthePartieswithrespecttothesubjectmatterhereofandthereof;provided ,however ,thattheConfidentialityAgreementshallnotbesupersededandshallremaininfullforceandeffectinaccordancewithitsterms.ThisAgreementmaybeexecutedinseveralcounterparts,eachofwhichshallbedeemedanoriginalandallofwhichshallconstituteoneandthesameinstrument.TheexchangeofafullyexecutedAgreement(incounterpartsorotherwise)byallPartiesbyfacsimileorelectronictransmissionin.PDFformatshallbesufficienttobindthePartiestothetermsandconditionsofthisAgreement.

10.5 Applicable Law; Jurisdiction .ThisAgreementshallbegovernedby,andconstruedinaccordancewith,thelawsoftheStateofDelaware,regardlessofthelawsthatmightotherwisegovernunderapplicableprinciplesofconflictsoflaws.InanyactionorsuitbetweenanyofthePartiesarisingoutoforrelatingtothisAgreementoranyoftheContemplatedTransactions:(a)eachofthePartiesirrevocablyandunconditionallyconsentsandsubmitstotheexclusivejurisdictionandvenueofthestateandfederalcourtslocatedintheStateofDelaware;and(b)eachofthePartiesirrevocablywaivestherighttotrialbyjury.

10.6 Attorneys’ Fees .InanyactionatlaworsuitinequitytoenforcethisAgreementortherightsofanyofthepartiesunderthisAgreement,theprevailingPartyinsuchactionorsuitshallbeentitledtoreceiveareasonablesumforitsattorneys’feesandallotherreasonablecostsandexpensesincurredinsuchactionorsuit.

10.7 Assignability; No Third Party Beneficiaries .ThisAgreementshallbebindingupon,andshallbeenforceablebyandinuresolelytothebenefitof,thePartiesheretoandtheirrespectivesuccessorsandassigns;provided ,however ,thatneitherthisAgreementnoranyofaParty’srightsorobligationshereundermaybeassignedordelegatedbysuchPartywithoutthepriorwrittenconsentofeachotherParty,andanyattemptedassignmentordelegationofthisAgreementoranyofsuchrightsorobligationsbysuchPartywithouteachotherParty’spriorwrittenconsentshallbevoidandofnoeffect.NothinginthisAgreement,expressorimplied,isintendedtoorshallconferuponanyPerson(otherthanthepartiesheretoandtheD&OIndemnifiedPartiestotheextentoftheirrespectiverightspursuanttoSection5.7)anyright,benefitorremedyofanynaturewhatsoeverunderorbyreasonofthisAgreement.

10.8 Notices .AnynoticeorothercommunicationrequiredorpermittedtobedeliveredtoanyPartyunderthisAgreementshallbeinwritingandshallbedeemedproperlydelivered,givenandreceivedwhendeliveredbyhand,byregisteredmail,bycourierorexpressdeliveryservice,electronicmail,orbyfacsimiletotheaddress,electronicmailaddress,orfacsimiletelephonenumbersetforthbeneaththenameofsuchPartybelow(ortosuchotheraddress,electronicmailaddress,orfacsimiletelephonenumberassuchPartyhasspecifiedinawrittennoticegiventotheotherpartieshereto):

iftoOpexaorMergerSub:

OpexaTherapeutics,Inc.

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2635TechnologyForestBlvd.TheWoodlands,TX77381TelephoneNo.:(281)719-3437FacsimileNo.:(281)872-8585Attention:NeilK.WarmaE-mail:nwarma@opexatherapeutics.com

withacopyto:

PillsburyWinthropShawPittmanLLP12255ElCaminoReal,Suite300SanDiego,California92130Telephone:(858)509-4000Fax:(858)509-4010Attention:MikeHirdE-mail:mike.hird@pillsburylaw.com

iftoAcer:

AcerTherapeuticsInc.222ThirdStreetSuite#2240Cambridge,MA02142TelephoneNo.:(844)902-6100FacsimileNo.:(617)225-7780Attention:HarryPalminE-mail:hpalmin@acertx.com

withacopyto:

FoleyHoagLLP155SeaportBoulevardBoston,MA02210TelephoneNo.:(617)832-1209FacsimileNo.:(617)832-7000Attention:DavidR.Pierson,Esq.andWilliamR.Kolb,Esq.E-Mail:DPierson@Foleyhoag.comandWRK@foleyhoag.com

10.9 Severability .AnytermorprovisionofthisAgreementthatisinvalidorunenforceableinanysituationinanyjurisdictionshallnotaffectthevalidityorenforceabilityoftheremainingtermsandprovisionsofthisAgreementorthevalidityorenforceabilityoftheoffendingtermorprovisioninanyothersituationorinanyotherjurisdiction.IfafinaljudgmentofacourtofcompetentjurisdictiondeclaresthatanytermorprovisionofthisAgreementisinvalidorunenforceable,thePartiesheretoagreethatthecourtmakingsuchdeterminationwillhavethepowertolimitsuchtermorprovision,todeletespecificwordsorphrasesortoreplacesuchtermorprovisionwithatermorprovisionthatisvalidandenforceableandthatcomesclosesttoexpressingtheintentionoftheinvalidorunenforceabletermorprovision,andthis

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Agreementshallbevalidandenforceableassomodified.Intheeventsuchcourtdoesnotexercisethepowergrantedtoitinthepriorsentence,thePartiesheretoagreetoreplacesuchinvalidorunenforceabletermorprovisionwithavalidandenforceabletermorprovisionthatwillachieve,totheextentpossible,theeconomic,businessandotherpurposesofsuchinvalidorunenforceabletermorprovision.

10.10 Other Remedies; Specific Performance .Exceptasotherwiseprovidedherein,anyandallremedieshereinexpresslyconferreduponaPartywillbedeemedcumulativewithandnotexclusiveofanyotherremedyconferredhereby,orbylaworequityuponsuchParty,andtheexercisebyaPartyofanyoneremedywillnotprecludetheexerciseofanyotherremedy.ThePartiesheretoagreethatirreparabledamagewouldoccurintheeventthatanyoftheprovisionsofthisAgreementwerenotperformedinaccordancewiththeirspecifictermsorwereotherwisebreached.ItisaccordinglyagreedthatthePartiesshallbeentitledtoaninjunctionorinjunctionstopreventbreachesofthisAgreementandtoenforcespecificallythetermsandprovisionshereofinanycourtoftheUnitedStatesoranystatehavingjurisdiction,thisbeinginadditiontoanyotherremedytowhichtheyareentitledatlaworinequity,andeachofthePartiesheretowaivesanybond,suretyorothersecuritythatmightberequiredofanyotherPartywithrespectthereto.

10.11 Construction .

(a) ForpurposesofthisAgreement,wheneverthecontextrequires:thesingularnumbershallincludetheplural,andviceversa;themasculinegendershallincludethefeminineandneutergenders;thefemininegendershallincludethemasculineandneutergenders;andtheneutergendershallincludemasculineandfemininegenders.

(b) ThePartiesheretoagreethatanyruleofconstructiontotheeffectthatambiguitiesaretoberesolvedagainstthedraftingPartyshallnotbeappliedintheconstructionorinterpretationofthisAgreement.

(c) AsusedinthisAgreement,thewords“include”and“including,”andvariationsthereof,shallnotbedeemedtobetermsoflimitation,butrathershallbedeemedtobefollowedbythewords“withoutlimitation.”Theword“or”whenusedinthisAgreementshallbedeemedtobeusedintheinclusivesenseof“and/or”,theword“any”whenusedinthisAgreementshallbedeemedtobeusedinthesenseof“anyandall”,andthewords“totheextent”whenusedinthisAgreementshallmeanthedegreetowhichasubjectorotheritemextendsandshallnotsimplymean“if”.AsusedinthisAgreement,thewords“hereof,”“herein,”“hereby,”“hereto,”and“hereunder”andwordsofsimilarimportwhenusedinthisAgreementshallrefertothisAgreementasawholeandnottoanyparticularprovisionofthisAgreement.

(d) Exceptasotherwiseindicated,allreferencesinthisAgreementtoanylegislationortoanyprovisionofanylegislationshallincludeanyamendmentthereto,andanymodificationorre-enactmentthereof,anylegislativeprovisionsubstitutedthereforandallregulationsandstatutoryinstrumentsissuedthereunderorpursuantthereto.

(e) Whencalculatingtheperiodoftimebeforewhich,withinwhichorfollowingwhich,anyactistobedoneorsteptakenpursuanttothisAgreement,thedatethatis

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thereferencedateincalculatingsuchperiodshallbeexcluded.Ifthelastdayofsuchperiodisanon-BusinessDay,theperiodinquestionshallendonthenextsucceedingBusinessDay.

(f) Exceptasotherwiseindicated,allreferencesinthisAgreementto“Sections,”“Articles,”“Exhibits”and“Schedules”areintendedtorefertoSectionsorArticlesofthisAgreementandExhibitsandSchedulestothisAgreement,respectively.

(g) Thebold-facedheadingscontainedinthisAgreementareforconvenienceofreferenceonly,shallnotbedeemedtobeapartofthisAgreementandshallnotbereferredtoinconnectionwiththeconstructionorinterpretationofthisAgreement.

[Remainder of page intentionally left blank ]

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IN WITNESS WHEREOF, thepartieshavecausedthisAgreementtobeexecutedasofthedatefirstabovewritten.

OPEXA THERAPEUTICS, INC.

By:/s/NeilK.WarmaName: NeilK.Warma

Title:

President,ChiefExecutiveOfficerandActingChiefFinancialOfficer

OPEXA MERGER SUB, INC.

By:/s/NeilK.WarmaName: NeilK.Warma

Title:

President,ChiefExecutiveOfficerandChiefFinancialOfficer

[SignaturePagetoAgreementandPlanofMergerandReorganization]

ACER THERAPEUTICS INC.

By:/s/ChrisSchellingName: ChrisSchellingTitle: PresidentandCEO

[SignaturePagetoAgreementandPlanofMergerandReorganization]

EXHIBIT A

CERTAIN DEFINITIONS

ForpurposesoftheAgreement(includingthisExhibitA):

“2010Plan”hasthemeaningsetforthinSection3.4(b).

“2013Plan”hasthemeaningsetforthinSection2.4(b).

“ ACA”hasthemeaningsetforthinSection2.14(o).

“ AccountingFirm”hasthemeaningsetforthinSection1.6(e).

“Acer”hasthemeaningsetforthinthePreamble.

“Acer409APlan”hasthemeaningsetforthinSection2.14(n).

“AcerAffiliate”meansanyPersonthatis(oratanyrelevanttimewas)undercommoncontrolwithAcerwithinthemeaningofSections414(b),(c),(m)and(o)oftheCode,andtheregulationsissuedthereunder.

“AcerAssociate”meansanycurrentemployee,independentcontractor,officerordirectorofAceroranyAcerAffiliate.

“AcerBoardAdverseRecommendationChange”hasthemeaningsetforthinSection5.2(b).

“AcerBoardofDirectors”meanstheboardofdirectorsofAcer.

“AcerBoardRecommendation”hasthemeaningsetforthinSection5.2(b).

“AcerCapitalStock”meanstheAcerCommonStockandtheAcerPreferredStock.

“AcerCommonStock”hasthemeaningsetforthinSection2.4(a).

“AcerContract”meansanyContract:(a)towhichAcerisaParty;or(b)bywhichAceroranyAcerIPRightsoranyotherassetofAcerisboundorunderwhichAcerhasanyobligation.

“AcerDisclosureSchedule”hasthemeaningsetforthinArticle2.

“AcerEmployeePlan”hasthemeaningsetforthinSection2.14(e).

“AcerFinancials”hasthemeaningsetforthinSection2.5(a).

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“AcerIPRights”meansallIntellectualPropertyowned,licensedorcontrolledbyAcerthatisnecessaryorusedinthebusinessofAceraspresentlyconductedoraspresentlyproposedtobeconducted.

“AcerIPRightsAgreement”meansanyinstrumentoragreementgoverning,relatedorpertainingtoanyAcerIPRights.

“AcerInterveningEvent”hasthemeaningsetforthinSection5.2(c).

“AcerLeases”hasthemeaningsetforthinSection2.8.

“AcerMaterialAdverseEffect”meansanyEffectthat,consideredtogetherwithallotherEffectsthathaveoccurredpriortothedateofdeterminationoftheoccurrenceoftheAcerMaterialAdverseEffect,isorwouldreasonablybeexpectedtobemateriallyadverseto,orhasorwouldreasonablybeexpectedtohaveorresultinamaterialadverseeffecton:(a)thebusiness,condition(financialorotherwise),capitalization,assets,operationsorfinancialperformanceofAcer;or(b)theabilityofAcertoconsummatetheContemplatedTransactionsortoperformanyofitscovenantsorobligationsundertheAgreementinallmaterialrespects;provided ,however ,thatEffectsfromthefollowingshallnotbedeemedtoconstitute(norshallEffectsfromanyofthefollowingbetakenintoaccountindeterminingwhethertherehasoccurred)anAcerMaterialAdverseEffect:(i)anyrejectionbyaGovernmentalBodyofaregistrationorfilingbyAcerrelatingtotheAcerIPRights;(ii)anychangeinthecashpositionofAcerwhichresultsfromoperationsintheOrdinaryCourseofBusiness;(iii)conditionsgenerallyaffectingtheindustriesinwhichAcerparticipatesortheUnitedStatesorglobaleconomyorcapitalmarketsasawhole,totheextentthatsuchconditionsdonothaveadisproportionateimpactonAcer;(iv)anyfailurebyAcertomeetinternalprojectionsorforecastsonorafterthedateofthisAgreement(itbeingunderstood,however,thatanyEffectcausingorcontributingtoanysuchfailuretomeetprojectionsorforecastsmayconstituteaAcerMaterialAdverseEffectandmaybetakenintoaccountindeterminingwhetheraAcerMaterialAdverseEffecthasoccurred);(v)theexecution,delivery,announcementorperformanceoftheobligationsunderthisAgreementortheannouncement,pendencyoranticipatedconsummationoftheMergerortheAcerPre-ClosingFinancing;(vi)anynaturaldisasteroranyactsofterrorism,sabotage,militaryactionorwaroranyescalationorworseningthereof;or(vii)anychanges(afterthedateofthisAgreement)inGAAPorapplicableLegalRequirements.

“AcerMaterialContract”hasthemeaningsetforthinSection2.10(a).

“AcerOptions”meansoptionstopurchasesharesofAcerCommonStockissuedorgrantedbyAcer.

“AcerPermits”hasthemeaningsetforthinSection2.12(b).

“AcerPre-ClosingFinancing”meanstheissuanceandsaleofAcerCommonStockinexchangeforgrossproceedsofatleast$15,500,000,whichmayconsistofconversionofupto$5,500,000inprincipalamountofseniorsecuredconvertiblepromissorynotesissuedbyAcerunderthatcertainNotePurchaseAgreementdatedMarch22,2017butwiththebalanceofthe

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grossproceedstobeincash(i.e. ,foraminimumof$10,000,000incash),tobeconsummatedpriortotheClosingpursuanttotheSubscriptionAgreement.

“AcerPreferredStock”hasthemeaningsetforthinSection2.4(a).

“AcerProductCandidates”hasthemeaningsetforthinSection2.12(d).

“AcerRegisteredIP”meansallAcerIPRightsthatareregistered,filedorissuedundertheauthorityof,withorbyanyGovernmentalBody,includingallpatents,registeredcopyrightsandregisteredtrademarksandallapplicationsforanyoftheforegoing.

“AcerRegulatoryPermits”hasthemeaningsetforthinSection2.12(d).

“AcerSeriesBPreferredStock”hasthemeaningsetforthinSection2.4(a).

“AcerStockCertificate”hasthemeaningsetforthinSection1.7.

“AcerStockholder”meanseachholderofAcerCapitalStock,and“AcerStockholders”meansallAcerStockholders.

“AcerStockholderMatters”hasthemeaningsetforthinSection5.2(a).

“AcerStockholderSupportAgreements”hasthemeaningsetforthintheRecitals.

“AcerStockholderWrittenConsent”hasthemeaningsetforthinSection2.2(b).

“AcerTerminationFee”hasthemeaningsetforthinSection9.3(b).

“AcerUnauditedInterimBalanceSheet”meanstheunauditedconsolidatedbalancesheetofAcerforthethree(3)monthperiodendingMarch31,2017.

“ AcquisitionAgreement”hasthemeaningsetforthinSection4.5(a).

“ AcquisitionInquiry”means,withrespecttoaParty,aninquiry,indicationofinterestorrequestforinformation(otherthananinquiry,indicationofinterestorrequestforinformationmadeorsubmittedbyAcer,ontheonehand,orOpexa,ontheotherhand,totheotherParty)thatwouldreasonablybeexpectedtoleadtoanAcquisitionProposalwithsuchParty.

“AcquisitionProposal”means,withrespecttoaParty,anyofferorproposal,whetherwrittenororal(otherthananofferorproposalmadeorsubmittedbyoronbehalfofAceroranyofitsAffiliates,ontheonehand,orbyoronbehalfofOpexaoranyofitsAffiliates,ontheotherhand,totheotherParty)madebyathirdpartycontemplatingorotherwiserelatingtoanyAcquisitionTransactionwithsuchParty.

“AcquisitionTransaction”meansanytransactionorseriesoftransactionsinvolving:(a)anydirectorindirectsale,lease,exchange,transfer,license,acquisitionordispositionofanybusinessorassetsofaPartyoranyofitsSubsidiaries(includinganyoutstandingequitysecuritiesofaSubsidiary)equalto10%ormoreofthefairmarketvalueofsuchParty’s

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consolidatedassetsortowhich10%ormoreofsuchParty’snetrevenuesornetincomeonaconsolidatedbasisareattributable;provided ,however ,thatanyacquisitionorlicensingofassetsofOpexaisexcludedfromthetransactionsdescribedinthisclause(a)solongassuchacquisitionorlicensing(i)doesnotincludetermsthatarenotreasonableandcustomaryfortransactionsofsimilarsize,typeandscope,(ii)wouldnotpreventordelayOpexafromenteringintoorconsummatingtheMergerandtheContemplatedTransaction,(iii)Acerisprovidedwiththeopportunitytoreviewinadvanceanybindingordefinitiveagreementand(iv)theproposedacquisitionorlicensing,ifconsummatedpriortotheEffectiveTime,doesnotcauseOpexatobecomeashellcompanyasdefinedinRule12b-2oftheExchangeAct;(b)anydirectorindirectacquisitionof10%ormoreoftheoutstandingequitysecuritiesofaParty;provided ,however ,thattheAcerPre-ClosingFinancingisexcludedfromthetransactionsdescribedinthisclause(b);(c)anytenderofferorexchangeofferthat,ifconsummated,wouldresultinanyPersonorgroupofPersonsbeneficiallyowning10%ormoreoftheoutstandingequitysecuritiesofaParty;(d)anyfinancingtransactionthatisunrelatedtotheAcerPre-ClosingFinancinginwhichAcerseekstoraisecapitalthroughtheissuanceofeitherequityordebtsecurities,oranyinstrumentconvertibleintoorexchangeableforsuchequityordebtsecurities,whetherfromexistinginvestorsorpotentialnewinvestors;provided ,however ,thatAcer’sissuanceofseniorsecuredconvertiblepromissorynotesunderthatcertainNotePurchaseAgreementdatedMarch22,2017attheAdditionalClosing(asdefinedtherein)isexcludedfromthetransactionsdescribedinthisclause(d);or(e)amerger,reversemerger,consolidation,otherbusinesscombinationorsimilartransactioninvolvingapartyheretooranyofitssubsidiaries;provided ,however ,thattheMergerandContemplatedTransactionsandanypotentialin-licensingtransactionsbyAcerortransactionsinvolvingtheacquisitionofpipelineproductsbyAcer,ineachcase,wheresuchtransactionsarecomplimentarytotheContemplatedTransactionsisexcludedfromthetransactionsdescribedinthisclause(e).

“Affiliates”hasthemeaningforsuchtermasusedinRule145undertheSecuritiesAct.

“Agreement”hasthemeaningsetforthinthePreamble.

“AllocationCertificate”hasthemeaningsetforthinSection1.12(b).

“AnticipatedClosingDate”hasthemeaningsetforthinSection1.6(a).

“BusinessDay”meansanydayotherthanadayonwhichbanksintheStateofNewYorkareauthorizedorobligatedtobeclosed.

“CertificateofMerger” hasthemeaningsetforthinSection1.3.

“Certifications” hasthemeaningsetforthinSection3.5(a).

“Closing” hasthemeaningsetforthinSection1.3.

“ClosingDate”hasthemeaningsetforthinSection1.3.

“COBRA”meanstheConsolidatedOmnibusBudgetReconciliationActof1985,asamended,assetforthinSection4980BoftheCodeandPart6ofTitleIofERISA.

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“Code”meanstheInternalRevenueCodeof1986,asamended.

“ConfidentialityAgreement”meanstheMutualConfidentialDisclosureAgreementbyandbetweenAcerandOpexa,datedasofJanuary10,2017,asamended.

“Consent”meansanyapproval,consent,ratification,permission,waiverorauthorization(includinganyGovernmentalAuthorization).

“ContemplatedTransactions”meanstheMerger,thePreferredStockConversion,theNASDAQReverseSplit,theAcerPre-ClosingFinancing,andtheothertransactionsandactionscontemplatedbytheAgreement.

“Contract”shall,withrespecttoanyPerson,meananywrittenagreement,contract,subcontract,lease(whetherrealorpersonalproperty),mortgage,understanding,arrangement,instrument,note,option,warranty,purchaseorder,license,sublicense,insurancepolicy,benefitplanorlegallybindingcommitmentorundertakingofanynaturetowhichsuchPersonisapartyorbywhichsuchPersonoranyofitsassetsareboundoraffectedunderapplicablelaw.

“Costs”hasthemeaningsetforthinSection5.7(a).

“D&OIndemnifiedParties”hasthemeaningsetforthinSection5.7(a).

“DeterminationDate”hasthemeaningsetforthinSection1.6(a).

“DGCL”meanstheGeneralCorporationLawoftheStateofDelaware.

“DisputeNotice”hasthemeaningsetforthinSection1.6(b).

“DissentingShares”hasthemeaningsetforthinSection1.9(a).

“DrugRegulatoryAgency”hasthemeaningsetforthinSection2.12(c).

“Effect”meansanyeffect,change,event,circumstance,ordevelopment.

“EffectiveTime” hasthemeaningsetforthinSection1.3.

“Encumbrance”meansanylien,pledge,hypothecation,charge,mortgage,securityinterest,encumbrance,claim,infringement,interference,option,rightoffirstrefusal,preemptiveright,communitypropertyinterestorrestrictionofanynature(includinganyrestrictiononthevotingofanysecurity,anyrestrictiononthetransferofanysecurityorotherasset,anyrestrictiononthereceiptofanyincomederivedfromanyasset,anyrestrictionontheuseofanyassetandanyrestrictiononthepossession,exerciseortransferofanyotherattributeofownershipofanyasset).

“Entity”meansanycorporation(includinganynon-profitcorporation),partnership(includinganygeneralpartnership,limitedpartnershiporlimitedliabilitypartnership),jointventure,estate,trust,company(includinganycompanylimitedbyshares,limitedliability

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companyorjointstockcompany),firm,societyorotherenterprise,association,organizationorentity,andeachofitssuccessors.

“EnvironmentalLaw”meansanyfederal,state,localorforeignLegalRequirementrelatingtopollutionorprotectionofhumanhealthortheenvironment(includingambientair,surfacewater,groundwater,landsurfaceorsubsurfacestrata),includinganylaworregulationrelatingtoemissions,discharges,releasesorthreatenedreleasesofHazardousMaterials,orotherwiserelatingtothemanufacture,processing,distribution,use,treatment,storage,disposal,transportorhandlingofHazardousMaterials.

“ERISA”meanstheEmployeeRetirementIncomeSecurityActof1974,asamended.

“ExchangeAct”meanstheSecuritiesExchangeActof1934,asamended.

“ExchangeAgent”hasthemeaningsetforthinSection1.8(a).

“ExchangeFund”hasthemeaningsetforthinSection1.8(a).

“ExchangeRatio”means,subjecttoSection1.5(f),thefollowingratio(withsuchratiobeingcalculatedtothenearest1/10,000ofashare):thequotientobtainedbydividing (a)theAcerMergerSharesby (b)theAcerOutstandingShares,inwhich:

• “AcerAllocationPercentage”means1.00minustheOpexaAllocationPercentage.

• “AcerMergerShares”meanstheproductdeterminedbymultiplying (a)thePost-ClosingOpexaSharesby (b)theAcerAllocationPercentage.

• “AcerOutstandingShares”meansthetotalnumberofsharesofAcerCommonStockoutstandingimmediatelypriortotheEffectiveTimeexpressedonafully-dilutedandas-convertedtoAcerCommonStockbasisandassuming,withoutlimitationorduplication,(a)theexerciseofallAcerOptionsoutstandingasofimmediatelypriortotheEffectiveTime,(b)theeffectivenessofthePreferredStockConversion,(c)theconsummationoftheAcerPre-ClosingFinancing(includingconversionofallseniorsecuredconvertiblepromissorynotesissuedbyAcerunderthatcertainNotePurchaseAgreementdatedMarch22,2017),(d)theconversionofallofAcer’soutstandingconvertibleindebtednessintosharesofAcerCommonStockand(e)theissuanceofsharesofAcerCommonStockinrespectofallotheroptions,warrantsorrightstoreceivesuchsharesthatwillbeoutstandingimmediatelypriortotheEffectiveTime.

• “ OpexaAllocationPercentage”meansthequotientdeterminedbydividing (i)thesumofSevenMillionDollars($7,000,000),plus orminus OneDollar($1)foreachOneDollar($1)thatNetCashdeterminedpursuanttoSection1.6isgreaterthanorlessthannegativeFiveHundredThousandDollars(-$500,000),by (ii)thesumof(A)theproductoftheAcerOutstandingSharesmultiplied by thepricepershareofAcerCommonStockforcashinvestorsinthePre-ClosingAcer

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Financing,plus (B)theamountdeterminedpursuanttotheforegoingclause(i),minus (C)theaggregateamountofanyindebtednessforborrowedmoneyofAceroutstandingattheClosing.Forexample,theOpexaAllocationPercentagewouldbe0.11147iftheNetCashdeterminedpursuanttoSection1.6isnegativeSixHundredThousandDollars(-$600,000),theproduct oftheAcerOutstandingSharesmultiplied by thepricepershareofAcerCommonStockforcashinvestorsinthePre-ClosingAcerFinancingisFifty-FiveMillionDollars($55,000,000),andAcerhasnoindebtednessforborrowedmoneyoutstandingattheClosing.

• “OpexaOutstandingShares”means,subjecttoSection1.5(f),thetotalnumberofsharesofOpexaCommonStockoutstandingimmediatelypriortotheEffectiveTimeexpressedonafully-dilutedandas-convertedtoOpexaCommonStockbasis,andassuming,withoutlimitationorduplication,(a)theexerciseofeachOpexaOptionoutstandingasoftheEffectiveTime,solelytotheextentsuchOpexaOptionwillnotbecanceledpursuanttoSection5.6(b)attheEffectiveTimeorexercisedpriorthereto,(b)thesettlementinsharesofOpexaCommonStockofeachOpexaRSUoutstandingasoftheEffectiveTime,solelytotheextentsuchOpexaRSUwillnotbecanceledpursuanttoSection5.6(b)attheEffectiveTimeorsettledpriorthereto,(c)theconversionofallofOpexa’soutstandingconvertibleindebtednessintosharesofOpexaCommonStock,and(d)theissuanceofsharesofOpexaCommonStockinrespectofallotheroptions,warrantsorrightstoreceivesuchsharesthatwillbeoutstandingimmediatelypriortotheEffectiveTime;provided ,however ,thatnotwithstandinganyelementoftheforegoing,allsharesofOpexaCommonStockunderlyingtheOpexaWarrantsshallbeexcludedfromthecalculationoftheOpexaOutstandingShares.

• “Post-ClosingOpexaShares”meanthequotientdeterminedbydividing (a)theOpexaOutstandingSharesby (b)theOpexaAllocationPercentage.

“ExistingAcerD&OPolicies”hasthemeaningsetforthinSection2.16(b).

“ExistingOpexaD&OPolicies”hasthemeaningsetforthinSection3.16(b).

“FDA”hasthemeaningsetforthinSection2.12(c).

“FDCA”hasthemeaningsetforthinSection2.12(c).

“Foley”hasthemeaningsetforthinSection5.1(c).

“FormS-4RegistrationStatement”meanstheregistrationstatementonFormS-4tobefiledwiththeSECbyOpexaregisteringthepublicofferingandsaleofOpexaCommonStocktoallAcerStockholdersintheMerger,includingallsharesofOpexaCommonStocktobeissuedinexchangeforallsharesofAcerCommonStockintheMerger,assaidregistrationstatementmaybeamendedpriortothetimeitisdeclaredeffectivebytheSEC.

“GAAP”hasthemeaningsetforthinSection2.5(a).

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“GovernmentalAuthorization”meansany:(a)permit,license,certificate,franchise,permission,variance,exceptions,orders,clearance,registration,qualificationorauthorizationissued,granted,givenorotherwisemadeavailablebyorundertheauthorityofanyGovernmentalBodyorpursuanttoanyLegalRequirement;or(b)rightunderanyContractwithanyGovernmentalBody.

“GovernmentalBody”meansany:(a)nation,state,commonwealth,province,territory,county,municipality,districtorotherjurisdictionofanynature;(b)federal,state,local,municipal,foreignorothergovernment;(c)governmentalorquasi-governmentalbodyofanynature(includinganygovernmentaldivision,department,agency,commission,instrumentality,official,ministry,fund,foundation,center,organization,unit,bodyorEntityandanycourtorothertribunal,andfortheavoidanceofdoubt,anyTaxauthority);or(d)self-regulatoryorganization(includingNASDAQandtheFinancialIndustryRegulatoryAuthority).

“GrantDate”hasthemeaningsetforthinSection2.14(f).

“HazardousMaterials”meansanypollutant,chemical,substanceandanytoxic,infectious,carcinogenic,reactive,corrosive,ignitableorflammablechemical,orchemicalcompound,orhazardoussubstance,materialorwaste,whethersolid,liquidorgas,thatissubjecttoregulation,controlorremediationunderanyEnvironmentalLaw,includingcrudeoiloranyfractionthereof,andpetroleumproductsorby-products.

“HSRAct”meanstheHart-Scott-RodinoAntitrustImprovementsActof1976,asamended.

“IntellectualProperty”means(a)UnitedStates,foreignandinternationalpatents,patentapplications,includingprovisionalapplications,statutoryinventionregistrations,inventiondisclosuresandinventions,(b)trademarks,servicemarks,tradenames,domainnames,URLs,tradedress,logosandothersourceidentifiers,includingregistrationsandapplicationsforregistrationthereof,(c)copyrights,includingregistrationsandapplicationsforregistrationthereof,and(d)software,formulae,customerlists,tradesecrets,know-how,confidentialinformationandotherproprietaryrightsandintellectualproperty,whetherpatentableornot.

“InvestorAgreements”shallhavethemeaningsetforthinSection5.17.

“IRS”meanstheUnitedStatesInternalRevenueService.

“Knowledge”means,(a)withrespecttoOpexa,theactualknowledgeofNeilK.Warma,afterdueinquiry;and(b)withrespecttoAcer,theactualknowledgeofChrisSchellingorHarryPalmin,ineachcase,afterdueinquiry.

“LegalProceeding”meansanyaction,suit,litigation,arbitration,proceeding(includinganycivil,criminal,administrative,investigativeorappellateproceeding),hearing,inquiry,audit,examinationorinvestigationcommenced,brought,conductedorheardbyorbefore,orotherwiseinvolving,anycourtorotherGovernmentalBodyoranyarbitratororarbitrationpanel.

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“LegalRequirement”meansanyfederal,state,foreign,materiallocalormunicipalorotherlaw,statute,constitution,principleofcommonlaw,resolution,ordinance,code,edict,decree,rule,regulation,rulingorrequirementissued,enacted,adopted,promulgated,implementedorotherwiseputintoeffectbyorundertheauthorityofanyGovernmentalBody.

“Liability”hasthemeaningsetforthinSection2.11.

“Merger”hasthemeaningsetforthintherecitals.

“MergerConsideration”hasthemeaningsetforthinSection1.5(a)(ii).

“MergerSub”hasthemeaningsetforthinthePreamble.

“MergerSubCapitalStock”hasthemeaningsetforthinSection3.4(e).

“MultiemployerPlan”means(a)a“multiemployerplan,”asdefinedinSection3(37)or4001(a)(3)ofERISA,or(b)aplanwhichifmaintainedoradministeredinorotherwisesubjecttothelawsoftheUnitedStateswouldbedescribedinparagraph(a).

“MultipleEmployerPlan”means(a)a“multipleemployerplan”withinthemeaningofSection413(c)oftheCodeorSection3(40)ofERISA,or(b)aplanwhichifmaintainedoradministeredinorotherwisesubjecttothelawsoftheUnitedStateswouldbedescribedinparagraph(a).

“NASDAQ”meansTheNASDAQStockMarket.

“NASDAQListingApplication”hasthemeaningsetforthinSection5.10.

“NASDAQReverseSplit”meansareversestocksplitofalloutstandingsharesofOpexaCommonStockatareversestocksplitratiointherangemutuallyagreedtobyOpexaandAcerthatiseffectedbyOpexaforthepurposeofmaintainingcompliancewithNASDAQlistingstandards.

“NetCash”means,asoftheClosingDateunlessotherwisespecified,(a)thesumofOpexa’scashandcashequivalents,determinedinamannerconsistentwiththemannerinwhichsuchitemswerehistoricallydeterminedandinaccordancewiththeOpexaAuditedFinancialStatementsandtheOpexaUnauditedInterimBalanceSheet,plus (b)anyreceivablesofOpexaasdeterminedinamannerconsistentwiththemannerinwhichsuchitemswerehistoricallydeterminedandinaccordancewiththeOpexaAuditedFinancialStatementsandtheOpexaUnauditedInterimBalanceSheet,andalsoincludingforthispurpose,andwithoutlimitation,anyfuturepayments(includingwithrespecttoanyPermittedOpexaAssetSale)thatwouldbereflectedinfinancialstatementsofOpexainaccordancewithGAAP,minus (c)thesumofOpexa’saccountspayableandaccruedexpenses(withoutduplicationofanyexpensesaccountedforbelow),ineachcaseasdeterminedinamannerconsistentwiththemannerinwhichsuchitemswerehistoricallydeterminedandinaccordancewiththeOpexaAuditedFinancialStatementsandtheOpexaUnauditedInterimBalanceSheet,minus (d)thecashcostofanyunpaidchangeofcontrolpaymentsorseverance,terminationorsimilarpaymentsthatareor

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becomedueasaresultoftheContemplatedTransactionstoanycurrentorformeremployee,directororindependentcontractorofOpexa,oranyotherthirdpartyminus (e)thecashcostofanyaccruedandunpaidretentionpaymentsorotherbonusesduetoanycurrentorformeremployee,directororindependentcontractorofOpexa,minus (f)anyremainingunpaidfeesandexpenses(includinganyattorney’s,accountant’s,financialadvisor’sorfinder’sfees)asofsuchdateforwhichOpexaisliableincurredbyOpexainconnectionwiththisAgreementandtheContemplatedTransactionsorotherwise,plus orminus (asapplicable)(g)thenetamountofanytransactionexpensereimbursementowedto,ortransactionexpensepaymentowedby,OpexapursuanttoSection9.3(a),minus (h)anyandallotherLiabilitiesofOpexathatwouldberequiredtobesetforthinabalancesheetpreparedinaccordancewithGAAP.

“NetCashCalculation”hasthemeaningsetforthinSection1.6(a).

“NetCashSchedule”hasthemeaningsetforthinSection1.6(a).

“NoticePeriod”hasthemeaningsetforthinSection5.2(c).

“Opexa401(k)Plan”hasthemeaningsetforthinSection5.6(c).

“Opexa409APlan”hasthemeaningsetforthinSection3.14(k).

“Opexa”hasthemeaningsetforthinthePreamble.

“OpexaAffiliate”meansanyPersonthatis(oratanyrelevanttimewas)undercommoncontrolwithOpexawithinthemeaningofSections414(b),(c),(m)and(o)oftheCode,andtheregulationsissuedthereunder.

“OpexaAssociate”meansanycurrentorformeremployee,independentcontractor,officerordirectorofOpexa,anyofitsSubsidiariesoranyOpexaAffiliate.

“OpexaAuditedFinancialStatements”meanstheauditedconsolidatedfinancialstatementsincludedinOpexa’sReportonForm10-KfiledwiththeSEConMarch28,2017fortheperiodendedDecember31,2016.

“OpexaBoardAdverseRecommendationChange”hasthemeaningsetforthinSection5.3(b).

“OpexaBoardofDirectors”meanstheboardofdirectorsofOpexa.

“OpexaBoardRecommendation”hasthemeaningsetforthinSection5.3(b).

“OpexaCapitalStock”meansOpexaCommonStockandOpexapreferredstock.

“OpexaCommonStock”hasthemeaningsetforthinSection3.4(a).

“OpexaContract”meansanyContract:(a)towhichOpexaoranOpexaSubsidiaryisaParty;or(b)bywhichOpexa,anOpexaSubsidiaryoranyOpexaIPRightsoranyotherassetof

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OpexaoranOpexaSubsidiaryisboundorunderwhichOpexaoranOpexaSubsidiaryhasanyobligation.

“OpexaDisclosureSchedule” hasthemeaningsetforthinArticle3.

“OpexaEmployeePlan” hasthemeaningsetforthinSection3.14(c).

“OpexaIPRights”meansallIntellectualPropertyowned,licensedorcontrolledbyOpexaoraOpexaSubsidiarythatisnecessaryorusedinthebusinessofOpexaoritsSubsidiariesaspresentlyconductedoraspresentlyproposedtobeconducted.

“OpexaIPRightsAgreement”meansanyinstrumentoragreementgoverning,relatedorpertainingtoanyOpexaIPRights.

“OpexaInterveningEvent”hasthemeaningsetforthinSection5.3(c).

“OpexaLeases”hasthemeaningsetforthinSection3.8.

“OpexaMaterialAdverseEffect”meansanyEffectthat,consideredtogetherwithallotherEffectsthathaveoccurredpriortothedateofdeterminationoftheoccurrenceoftheOpexaMaterialAdverseEffect,isorwouldreasonablybeexpectedtobeortobecomemateriallyadverseto,orhasorwouldreasonablybeexpectedtohaveorresultinamaterialadverseeffecton:(a)thebusiness,condition(financialorotherwise),capitalization,assets,operationsorfinancialperformanceofOpexa;or(b)theabilityofOpexatoconsummatetheContemplatedTransactionsortoperformanyofitscovenantsorobligationsundertheAgreementinallmaterialrespects;provided ,however ,thatEffectsfromthefollowingshallnotbedeemedtoconstitute(norshallEffectsfromanyofthefollowingbetakenintoaccountindeterminingwhethertherehasoccurred)anOpexaMaterialAdverseEffect:(i)anyrejectionbyaGovernmentalBodyofaregistrationorfilingbyOpexarelatingtotheOpexaIPRights;(ii)anychangeinthecashpositionofOpexawhichresultsfromoperationsintheOrdinaryCourseofBusiness;(iii)conditionsgenerallyaffectingtheindustriesinwhichOpexaparticipatesortheUnitedStatesorglobaleconomyorcapitalmarketsasawhole,totheextentthatsuchconditionsdonothaveadisproportionateimpactonOpexa;(iv)anyfailureofOpexatomeetinternalprojectionsorforecastorthird-partyrevenueorearningspredictionsforanyperiodending(orforwhichrevenuesorearningsarereleased)onorafterthedateofthisAgreementoranychangeinthepriceortradingvolumeofOpexaCommonStock(itbeingunderstood,however,thatanyEffectcausingorcontributingtoanysuchfailuretomeetprojectionsorpredictionsoranychangeinstockpriceortradingvolumemayconstituteanOpexaMaterialAdverseEffectandmaybetakenintoaccountindeterminingwhetheranOpexaMaterialAdverseEffecthasoccurred);(v)theconsummationofaPermittedOpexaAssetSale,(vi)theexecution,delivery,announcementorperformanceoftheobligationsunderthisAgreementortheannouncement,pendencyoranticipatedconsummationoftheMergerortheAcerPre-ClosingFinancing;(vii)anynaturaldisasteroranyactsofterrorism,sabotage,militaryactionorwaroranyescalationorworseningthereof;or(viii)anychanges(afterthedateofthisAgreement)inGAAPorapplicableLegalRequirements.

“OpexaMaterialContract” hasthemeaningsetforthinSection3.10.

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“OpexaOptions”meansoptionstopurchasesharesofOpexaCommonStockissuedorgrantedbyOpexa.

“OpexaOutstandingSharesCertificate”hasthemeaningsetforthinSection1.12(a).

“OpexaPermits” hasthemeaningsetforthinSection3.12(b).

“OpexaRegisteredIP”meansallOpexaIPRightsthatareregistered,filedorissuedundertheauthorityof,withorbyanyGovernmentalBody,includingallpatents,registeredcopyrightsandregisteredtrademarksandallapplicationsforanyoftheforegoing.

“OpexaRegulatoryPermits” hasthemeaningsetforthinSection3.12(d).

“OpexaRSUs”meansarestrictedstockunitcoveringsharesofOpexaCapitalStockissuedorgrantedbyOpexa.

“OpexaShareholder”meanseachholderofOpexaCapitalStock,and“OpexaShareholder”meansallOpexaShareholders.

“OpexaShareholderMatters”hasthemeaningsetforthinSection5.3(a).

“OpexaShareholders’Meeting”hasthemeaningsetforthinSection5.3(a).

“OpexaShareholderSupportAgreements”hasthemeaningsetforthintheRecitals.

“OpexaSubsidiaries”hasthemeaningsetforthinSection3.1(a).

“OpexaTerminationFee”hasthemeaningsetforthinSection9.3(b).

“OpexaUnauditedInterimBalanceSheet”meanstheunauditedconsolidatedbalancesheetofOpexaincludedinOpexa’sReportonForm10-QfiledwiththeSECfortheperiodendedMarch31,2017.

“OpexaWarrants”meanstheoutstandingwarrantstopurchaseOpexaCapitalStocksetforthinSection3.4(a)oftheOpexaDisclosureSchedule.

“OrdinaryCourseofBusiness”means,inthecaseofeachofAcerandOpexaandforallperiods,suchactionstakenintheordinarycourseofitsnormaloperationsandconsistentwithitspastpractices;provided, however, thatduringthePre-ClosingPeriod,(a)theOrdinaryCourseofBusinessofeachPartyshallalsoincludeanyactionsexpresslyrequiredorpermittedbythisAgreement,includingtheContemplatedTransactions,and(b)theOrdinaryCourseofBusinessforAcershallalsoincludeactionsundertakeninconnectionwithpreparingtobecomeaSECreportingcompanylistedontheNASDAQCapitalMarketand.

“OutsideDate”hasthemeaningsetforthinSection9.1(b).

“Party”or“Parties”meansAcer,MergerSubandOpexa.

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“PermittedAlternativeAgreement”meansanAcquisitionAgreementthatconstitutesaSuperiorOffer.

“PermittedOpexaAssetSale”hasthemeaningsetforthinSection4.2(b)(viii).

“Person”meansanyindividual,EntityorGovernmentalBody.

“Pillsbury”hasthemeaningsetforthinSection5.1(c).

“Pre-ClosingPeriod”hasthemeaningsetforthinSection4.1.

“PreferredStockConversion”hasthemeaningsetforthinSection5.16.

“ProxyStatement/Prospectus/InformationStatement”meanstheproxystatement/prospectus/informationstatementtobesenttoAcer’sstockholdersinconnectionwiththeapprovalofthisAgreementandtheMerger(bysigningtheAcerStockholderWrittenConsent)andtoOpexa’sshareholdersinconnectionwiththeOpexaShareholders’Meeting.

“Representatives”meansdirectors,officers,otheremployees,agents,attorneys,accountants,investmentbankers,advisorsandrepresentatives.

“RequiredAcerStockholderVote”hasthemeaningsetforthinSection2.2(b).

“RequiredMergerSubStockholderVote”hasthemeaningsetforthinSection3.2(b).

“RequiredOpexaShareholderVote”hasthemeaningsetforthinSection3.2(b).

“ResponseDate”hasthemeaningsetforthinSection1.6(b).

“Sarbanes-OxleyAct”meanstheSarbanes-OxleyActof2002,asitmaybeamendedfromtimetotime.

“SEC”meanstheUnitedStatesSecuritiesandExchangeCommission.

“SecuritiesAct”meanstheSecuritiesActof1933,asamended.

“SubscriptionAgreement”hasthemeaningsetforthintheRecitals.

“SubsequentTransaction”meansanyAcquisitionTransaction(withallreferencesto10%inthedefinitionofAcquisitionTransactionbeingtreatedasreferencesto50%forthesepurposes).

“Subsidiary”meansanEntityofwhichanotherPersondirectlyorindirectlyownsorpurportstoown,beneficiallyorofrecord,(a)anamountofvotingsecuritiesofotherinterestsinsuchEntitythatissufficienttoenablesuchPersontoelectatleastamajorityofthemembersofsuchEntity’sboardofdirectorsorothergoverningbody,or(b)atleast50%oftheoutstandingequity,voting,beneficialorfinancialinterestsinsuchEntity.

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“SuperiorOffer”meansanunsolicited,bonafideAcquisitionProposal(withallreferencesto10%inthedefinitionofAcquisitionTransactionbeingtreatedasreferencesto50%forthesepurposes)madebyathirdpartythat(a)wasnotobtainedormadeasadirectorindirectresultofabreachof(orinviolationof)thisAgreement;and(b)isontermsandconditionsthattheOpexaBoardofDirectorsortheAcerBoardofDirectors,asapplicable,determines,initsreasonable,goodfaithjudgment,afterobtainingandtakingintoaccountsuchmattersthatitsBoardofDirectorsdeemsrelevantfollowingconsultationwithitsoutsidelegalcounselandfinancialadvisor,ifany(i)ismorefavorable,fromafinancialpointofview,totheOpexaShareholdersortheAcerStockholders,asapplicable,thanthetermsoftheMerger;and(ii)isreasonablycapableofbeingconsummated;provided ,however ,thatanysuchoffershallnotbedeemedtobea“SuperiorOffer”if(A)anyfinancingrequiredtoconsummatethetransactioncontemplatedbysuchofferisnotcommittedandisnotreasonablycapableofbeingobtainedbysuchthirdpartyor(B)iftheconsummationofsuchtransactioniscontingentonanysuchfinancingbeingobtained.

“SurvivingCorporation”hasthemeaningsetforthinSection1.1.

“Tax”meansanyfederal,state,local,foreignorothertax,includinganyincometax,franchisetax,capitalgainstax,grossreceiptstax,value-addedtax,surtax,estimatedtax,unemploymenttax,nationalhealthinsurancetax,excisetax,advaloremtax,transfertax,stamptax,salestax,usetax,propertytax,businesstax,withholdingtax,payrolltax,customsduty,alternativeoradd-onminimumorothertaxofanykindwhatsoever,andincludinganyfine,penalty,additiontotaxorinterest,whetherdisputedornot.

“TaxReturn”meansanyreturn(includinganyinformationreturn),report,statement,declaration,estimate,schedule,notice,notification,form,election,certificateorotherdocumentorinformation,andanyamendmentorsupplementtoanyoftheforegoing,filedwithorsubmittedto,orrequiredtobefiledwithorsubmittedto,anyGovernmentalBodyinconnectionwiththedetermination,assessment,collectionorpaymentofanyTaxorinconnectionwiththeadministration,implementationorenforcementoforcompliancewithanyLegalRequirementrelatingtoanyTax.

“TBOC”meanstheTexasBusinessOrganizationsCode.

“TerminatedOpexaAssociatePayments”hasthemeaningsetforthinSection5.6(a).

“TreasuryRegulations”meanstheUnitedStatesTreasuryregulationspromulgatedundertheCode.

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Exhibit 2.2

SUPPORT AGREEMENT

ThisSUPPORT AGREEMENT (this“Agreement”),datedasofJune30,2017,isbyandamongAcerTherapeuticsInc.(“Acer”),andthePersonsetforthonScheduleAhereto(the“Shareholder”).

WHEREAS ,asofthedatehereof,theShareholderistheholderofthenumberofsharesofcommonstock,parvalue$0.01pershare(the“CommonStock”),ofOpexaTherapeutics,Inc.,aTexascorporation(“Opexa”),setforthoppositetheShareholder’snameonScheduleA(allsuchsharessetforthonScheduleA,togetherwithanysharesofCommonStockthatarehereafterissuedtoorotherwiseacquiredorownedbytheShareholderpriortotheterminationofthisAgreementbeingreferredtohereinasthe“SubjectShares”);

WHEREAS ,Acer,OpexaMergerSub,Inc.,aDelawarecorporationandadirectwhollyownedsubsidiaryofOpexa(“MergerSub”)andOpexaproposetoenterintoanAgreementandPlanofMergerandReorganization,datedasofthedatehereof(the“MergerAgreement”),whichprovides,amongotherthings,forthemergerofMergerSubwithandintoAcer,withAcercontinuingasthesurvivingcorporation(the“Merger”),uponthetermsandsubjecttotheconditionssetforthintheMergerAgreement(capitalizedtermsusedbutnototherwisedefinedhereinshallhavetherespectivemeaningsascribedtosuchtermsintheMergerAgreement);and

WHEREAS ,asaconditiontoitswillingnesstoenterintotheMergerAgreement,AcerhasrequiredthattheShareholder,andasaninducementandinconsiderationtherefor,theShareholder(intheShareholder’scapacityasaholderoftheSubjectShares)hasagreedto,enterintothisAgreement.

NOW, THEREFORE ,inconsiderationoftheforegoingandtherespectiverepresentations,warranties,covenantsandagreementssetforthbelowandforothergoodandvaluableconsideration,thereceiptandsufficiencyofwhichareherebyacknowledged,thepartieshereto,intendingtobelegallybound,doherebyagreeasfollows:

ARTICLE I

VOTING AGREEMENT; GRANT OF PROXY

TheShareholderherebycovenantsandagreesthat:

1.1.Voting of Subject Shares .AteverymeetingoftheholdersofOpexaCommonStock(the“OpexaShareholders”),howevercalled,andateveryadjournmentorpostponementthereof(orpursuanttoawrittenconsentiftheOpexaShareholdersactbywrittenconsentinlieuofameeting),theShareholdershall,orshallcausetheholderofrecordonanyapplicablerecorddateto,bepresent(inpersonorbyproxy)andtovotetheSubjectShares(a)infavorof(i)theissuanceofsharesofCommonStocktotheAcerShareholderspursuanttothetermsoftheMergerAgreement,(ii)thechangeofcontrolofOpexaresultingfromtheMerger,(iii)ifrequestedbyAcer,theamendmentofOpexa’scertificateofformationtoeffecttheNASDAQReverseSplit,(iv)theamendmentofOpexa’scertificateofformationtoeffectthenamechangeofOpexa,(v)anyPermittedOpexaAssetSale,totheextentrequiredandnotpreviouslyapprovedbytheOpexaShareholders,and(vi)anyproposalsubmittedtotheOpexaShareholdersinaccordancewithSection14AoftheExchangeActandtheapplicableSECrulesissuedthereunder,seekingapprovalforanon-binding,advisoryvotetoapprovecertaincompensationthatmaybecomepayabletoOpexa’snamedexecutedofficerinconnectionwiththecompletionoftheMerger,ifapplicable;and(b)againstanyAcquisitionProposal.

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1.2.No Inconsistent Arrangements .ExceptasprovidedhereunderorundertheMergerAgreement,theShareholdershallnot,directlyorindirectly,(a)createanyEncumbranceotherthanrestrictionsimposedbyLegalRequirementsorpursuanttothisAgreementonanySubjectShares,(b)transfer,sell,assign,giftorotherwisedisposeof(collectively,“Transfer”),orenterintoanycontractwithrespecttoanyTransferoftheSubjectSharesoranyinteresttherein,(c)grantorpermitthegrantofanyproxy,powerofattorneyorotherauthorizationinorwithrespecttotheSubjectShares,(d)depositorpermitthedepositoftheSubjectSharesintoavotingtrustorenterintoavotingagreementorarrangementwithrespecttotheSubjectShares,or(e)takeanyactionthat,totheknowledgeoftheShareholder,wouldmakeanyrepresentationorwarrantyoftheShareholderhereinuntrueorincorrectinanymaterialrespect,orhavetheeffectofpreventingtheShareholderfromperformingitsobligationshereunder.Notwithstandingtheforegoing,(i)theShareholdermay(A)maketransfersoftheSubjectSharesascharitablegiftsordonations,(B)maketransfersordispositionsoftheSubjectSharestoanytrustforthedirectorindirectbenefitoftheShareholderortheimmediatefamilyoftheShareholder,(C)maketransfersordispositionsoftheSubjectSharesbywill,othertestamentarydocumentorintestatesuccessiontothelegalrepresentative,heir,beneficiaryoramemberoftheimmediatefamilyoftheShareholder,(D)maketransfersoftheSubjectSharestoshareholders,directorindirectaffiliates(withinthemeaningsetforthinRule405undertheSecuritiesActof1933,asamended),currentorformerpartners(generalorlimited),membersormanagersoftheShareholder,asapplicable,ortotheestatesofanysuchshareholders,affiliates,partners,membersormanagers,ortoanothercorporation,partnership,limitedliabilitycompanyorotherbusinessentitythatcontrols,iscontrolledbyorisundercommoncontrolwiththeShareholder,(E)maketransfersoftheSubjectSharesthatoccurbyoperationoflawpursuanttoaqualifieddomesticorderorinconnectionwithadivorcesettlement,(F)maketransfersordispositionsoftheSubjectSharesnotinvolvingachangeinbeneficialownership,(G)iftheShareholderisatrust,maketransfersordispositionsoftheSubjectSharestoanybeneficiaryoftheShareholderortheestateofanysuchbeneficiary,providedthat,ineachcase,thetransfereeagreesinwritingtobeboundbythetermsandconditionsofthisAgreementandeithertheShareholderorthetransfereeprovidesAcerwithacopyofsuchagreementpromptlyuponconsummationofanysuchTransferand(ii)theShareholdermaytakeallactionsreasonablynecessarytoconsummatetheContemplatedTransactions,including,withoutlimitation,effectingtheNASDAQReverseSplit.

1.3.No Exercise of Appraisal Rights; Waivers .TheShareholderhereby(a)waivesandagreesnottoexerciseanydissenters’orappraisalrights,orothersimilarrights,withrespecttoanySubjectSharesthatmayariseinconnectionwiththeContemplatedTransactionsand(b)agreesthatitwillnotbring,commence,institute,maintain,prosecute,participateinorvoluntarilyaidanyaction,claim,suitorcauseofaction,inlaworinequity,inanycourtorbeforeanyGovernmentalBody,which(i)challengesthevalidityoforseekstoenjointheoperationofanyprovisionofthisAgreementor(ii)allegesthattheexecutionanddeliveryofthisAgreementbytheShareholder,ortheapprovaloftheMergerAgreementbytheOpexaBoardofDirectors,breachesanyfiduciarydutyoftheOpexaBoardofDirectorsoranymemberthereof;provided , that theShareholdermaydefendagainst,contestorsettleanysuchaction,claim,suitorcauseofactionbroughtagainsttheShareholderthatrelatessolelytotheShareholder’scapacityasadirector,officerorsecurityholderofOpexa.

1.4.Documentation and Information .TheShareholdershallpermitandherebyauthorizesOpexaandAcertopublishanddiscloseinalldocumentsandschedulesfiledwiththeSEC,andanyotherdisclosuredocumentthatOpexaorAcerreasonablydeterminestoberequiredbyapplicablelawinconnectionwiththeMergerandanytransactionscontemplatedbytheMergerAgreement,theShareholder’sidentityandownershipoftheSubjectSharesandthenatureoftheShareholder’scommitmentsandobligationsunderthisAgreement;providedthatOpexaorAcer,asthecasemaybe,

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shallaffordtheShareholderreasonableadvancednoticetoreviewandcommentonsuchdisclosure.Opexaisanintendedthird-partybeneficiaryofthisSection1.4.

1.5.Irrevocable Proxy . TheShareholderherebyrevokes(oragreestocausetoberevoked)anyproxiesthattheShareholderhasheretoforegrantedwithrespecttotheSubjectShares.TheShareholderherebyirrevocablyappointsAcerasattorney-in-factandproxyforandonbehalfoftheShareholder,forandinthename,placeandsteadoftheShareholder,to:(a)attendanyandallmeetingsofOpexaShareholdersheldforthemattersaddressedinSection1.1,(b)vote,expressconsentordissentorissueinstructionstotherecordholdertovotetheSubjectSharessolelyinfurtheranceoftheprovisionsofSection1.1atanyandallmeetingsofOpexaShareholdersorinconnectionwithanyactionsoughttobetakenbywrittenconsentofOpexaShareholderswithoutameetingand(c)grantorwithhold,orissueinstructionstotherecordholdertograntorwithhold,consistentwiththeprovisionsofSection1.1,allwrittenconsentswithrespecttotheSubjectSharesatanyandallmeetingsofOpexaShareholdersorinconnectionwithanyactionsoughttobetakenbywrittenconsentofOpexaShareholderswithoutameeting,inanycasesolelyinfurtheranceoftheprovisionsofSection1.1.AceragreesnottoexercisetheproxygrantedhereinforanypurposeotherthanthepurposesdescribedinthisAgreement.Theforegoingproxyshallbedeemedtobeaproxycoupledwithaninterest,isirrevocable(andassuchshallsurviveandnotbeaffectedbythedeath,incapacity,mentalillnessorinsanityoftheShareholder,asapplicable)untiltheterminationoftheMergerAgreementandshallnotbeterminatedbyoperationoflaworupontheoccurrenceofanyothereventotherthantheterminationofthisAgreementpursuanttoSection4.2.TheShareholderauthorizessuchattorneyandproxytosubstituteanyotherPersontoacthereunder,torevokeanysubstitutionandtofilethisproxyandanysubstitutionorrevocationwiththeSecretaryofOpexa.TheShareholderherebyaffirmsthattheproxysetforthinthisSection1.5isgiveninconnectionwithandgrantedinconsiderationofandasaninducementtoAcertoenterintotheMergerAgreementandthatsuchproxyisgiventosecuretheobligationsoftheShareholderunderSection1.1.TheproxysetforthinthisSection1.5isexecutedandintendedtobeirrevocable,subject,however,toitsautomaticterminationupontheterminationofthisAgreementpursuanttoSection4.2.WithrespecttoanySubjectSharesthatareownedbeneficiallybytheShareholderbutarenotheldofrecordbytheShareholder,theShareholdershalltakeallactionnecessarytocausetherecordholderofsuchSubjectSharestogranttheirrevocableproxyandtakeallotheractionsprovidedforinthisSection1.5withrespecttosuchSubjectShares.

1.6.No Solicitation of Transactions .TheShareholdershallnotknowingly,directlyorindirectly,throughanyofficer,director,agentorotherwise,(a)solicit,initiate,respondtoorknowinglytakeanyactiontofacilitateorencourageanyinquiriesorthecommunication,making,submissionorannouncementofanyAcquisitionProposalorAcquisitionInquiryortakeanyactionthatcouldreasonablybeexpectedtoleadtoanAcquisitionProposalorAcquisitionInquiry;(b)enterintoorparticipateinanydiscussionsornegotiationswithanyPersonwithrespecttoanyAcquisitionProposalorAcquisitionInquiry;(c)furnishanyinformationregardingsuchpartytoanyPersoninconnectionwith,inresponseto,relatingtoorforthepurposeofassistingwithorfacilitatinganAcquisitionProposalorAcquisitionInquiry;or(d)approve,endorseorrecommendanyAcquisitionProposal.TheShareholderherebyrepresentsandwarrantsthathe,sheorithasreadSection4.5oftheMergerAgreementandagreesnottoengageinanyactionsprohibitedthereby.

1.7.No Ownership Interest .NothingcontainedinthisAgreementwillbedeemedtovestinAceranydirectorindirectownershiporincidentsofownershipoforwithrespecttotheSubjectShares.Allrights,ownershipandeconomicbenefitsofandrelatingtotheSubjectShareswillremainandbelongtotheShareholder,andAcerwillhavenoauthoritytomanage,direct,superintend,restrict,regulate,governoradministeranyofthepoliciesoroperationsofOpexaorexerciseanypowerorauthoritytodirectthe

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ShareholderinthevotingofanyoftheSubjectShares,exceptasotherwiseexpresslyprovidedhereinwithrespecttotheSubjectSharesandexceptasotherwiseexpresslyprovidedintheMergerAgreement.

ARTICLE II

REPRESENTATIONS AND WARRANTIES OF THE SHAREHOLDER

TheShareholderrepresentsandwarrantstoAcerthat:

2.1.Organization; Authorization; Binding Agreement .TheShareholder,ifnotanaturalperson,isdulyincorporatedororganized,asapplicable,validlyexistingandingoodstandingunderthelawsofitsjurisdictionofincorporationororganization.TheShareholderhasfulllegalcapacityandpower,rightandauthoritytoexecuteanddeliverthisAgreementandtoperformhis,heroritsobligationshereunderandtoconsummatethetransactionscontemplatedhereby.ThisAgreementhasbeendulyandvalidlyexecutedanddeliveredbytheShareholder,andconstitutesavalidandbindingobligationoftheShareholderenforceableagainsttheShareholderinaccordancewithitsterms,subjectto(a)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtorsand(b)lawsofgeneralapplicationrelatingtobankruptcy,insolvency,thereliefofdebtors,fraudulenttransfer,reorganization,moratoriumandothersimilarlawsofgeneralapplicabilityrelatingtooraffectingcreditor’srights(the“EnforceabilityExceptions”).

2.2.Ownership of Subject Shares; Total Shares .TheShareholderistherecordorbeneficialowner(asdefinedinRule13d-3undertheExchangeAct)oftheSubjectSharesandhasgoodandmarketabletitletotheSubjectSharesfreeandclearofanyEncumbrances(includinganyrestrictionontherighttovoteorotherwisetransfertheSubjectShares),except(a)asprovidedhereunder,(b)pursuanttoanyapplicablerestrictionsontransferundertheSecuritiesAct,and(c)subjecttoanyriskofforfeiturewithrespecttoanysharesofCommonStockgrantedtotheShareholderunderanemployeebenefitplanofOpexa.TheSubjectShareslistedonScheduleAoppositetheShareholder’snameconstituteallofthesharesofCommonStockownedbytheShareholderasofthedatehereof.NoPersonhasanycontractualorotherrightorobligationtopurchaseorotherwiseacquireanyoftheSubjectShares.

2.3.Voting Power .TheShareholderhasfullvotingpower,withrespecttotheSubjectShares,andfullpowerofdisposition,fullpowertoissueinstructionswithrespecttothematterssetforthhereinandfullpowertoagreetoallofthematterssetforthinthisAgreement,ineachcase,withrespecttoalloftheSubjectShares.NoneoftheSubjectSharesaresubjecttoanyproxy,votingtrustorotheragreementorarrangementwithrespecttothevotingoftheSubjectShares,exceptasprovidedhereunder.

2.4.Reliance .TheShareholderhashadtheopportunitytoreviewtheMergerAgreementandthisAgreementwithcounseloftheShareholder’sownchoosing.TheShareholderunderstandsandacknowledgesthatAcerisenteringintotheMergerAgreementinrelianceupontheShareholder’sexecution,deliveryandperformanceofthisAgreement.

2.5.Absence of Litigation .WithrespecttotheShareholder,asofthedatehereof,thereisnoaction,suit,investigationorproceedingpendingagainst,or,totheknowledgeoftheShareholder,threatenedinwritingagainst,theShareholderoranyoftheShareholder’spropertiesorassets(includingtheSubjectShares)thatcouldreasonablybeexpectedtoprevent,delayorimpairtheabilityoftheShareholdertoperformitsobligationshereunderortoconsummatethetransactionscontemplatedhereby.

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ARTICLE III

REPRESENTATIONS AND WARRANTIES OF ACER

AcerrepresentsandwarrantstotheShareholderthat:

3.1.Organization; Authorization .Acerisacorporationdulyincorporated,validlyexistingandingoodstandingunderthelawsoftheStateofDelaware.TheconsummationofthetransactionscontemplatedherebyiswithinAcer’scorporatepowersandhasbeendulyauthorizedbyallnecessarycorporateactionsonthepartofAcer.Acerhasfullpowerandauthoritytoexecute,deliverandperformthisAgreement.

3.2.Binding Agreement .ThisAgreementhasbeendulyauthorized,executedanddeliveredbyAcerandconstitutesavalidandbindingobligationofAcerenforceableagainstAcerinaccordancewithitsterms,subjecttotheEnforceabilityExceptions.

ARTICLE IV

MISCELLANEOUS

4.1.Notices .Allnotices,requestsandothercommunicationstoeitherpartyhereundershallbeinwriting(includingfacsimiletransmissionorelectronicmail)andshallbegiven,(a)iftoAcer,inaccordancewiththeprovisionsoftheMergerAgreementand(b)iftotheShareholder,totheShareholder’saddress,electronicmailaddressorfacsimilenumbersetforthonasignaturepagehereto,ortosuchotheraddress,electronicaddressorfacsimilenumberastheShareholdermayhereafterspecifyinwritingtoAcerforthepurposebynoticetoAcer.

4.2.Termination .ThisAgreementshallterminateautomatically,withoutanynoticeorotheractionbyanyPerson,upontheearlierof(a)theterminationoftheMergerAgreementinaccordancewithitstermsand(b)theEffectiveTime.UponterminationofthisAgreement,neitherpartyshallhaveanyfurtherobligationsorliabilitiesunderthisAgreement;provided, however, that(i)nothingsetforthinthisSection4.2shallrelieveeitherpartyfromliabilityforanybreachofthisAgreementpriortoterminationhereof,and(ii)theprovisionsofthisArticleIVshallsurviveanyterminationofthisAgreement.

4.3.Amendments and Waivers .AnyprovisionofthisAgreementmaybeamendedorwaivedifsuchamendmentorwaiverisinwritingandissigned,inthecaseofanamendment,bytheShareholderandAcer,inthecaseofawaiver,bythepartyagainstwhomthewaiveristobeeffective.Nofailureordelaybyeitherpartyinexercisinganyright,powerorprivilegehereundershalloperateasawaiverthereofnorshallanysingleorpartialexercisethereofprecludeanyotherorfurtherexercisethereofortheexerciseofanyotherright,powerorprivilege.

4.4.Binding Effect; Benefit; Assignment .TheprovisionsofthisAgreementshallbebindinguponandshallinuretothebenefitofthepartiesheretoandtheirrespectivesuccessorsandassigns.ExceptassetforthinSection1.4,noprovisionofthisAgreementisintendedtoconferanyrights,benefits,remedies,obligationsorliabilitieshereunderuponanypersonotherthanthepartiesheretoandtheirrespectivesuccessorsandassigns.Neitherpartymayassign,delegateorotherwisetransferanyofitsrightsorobligationsunderthisAgreementwithouttheconsentoftheotherpartyhereto,exceptthatAcermaytransferorassignitsrightsandobligationsunderthisAgreement,inwholeorfromtimetotimein

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part,tooneormoreofitsAffiliatesatanytime;provided,thatsuchtransferorassignmentshallnotrelieveAcerofanyofitsobligationshereunder.

4.5.Governing Law; Jurisdiction .ThisAgreementshallbegovernedby,andconstruedinaccordancewith,thelawsoftheStateofDelaware,regardlessofthelawsthatmightotherwisegovernunderapplicableprinciplesofconflictsoflaws.InanyactionorsuitbetweenanyofthepartiesarisingoutoforrelatingtothisAgreement:(a)eachofthepartiesirrevocablyandunconditionallyconsentsandsubmitstotheexclusivejurisdictionandvenueoftheDelawareCourtofChancery,orifsuchcourtdoesnothaveproperjurisdiction,thenthefederalcourtslocatedintheStateofDelaware,andappellatecourtstherefrom,(collectively,the“DelawareCourts”);and(b)eachofthepartiesirrevocablywaivestherighttotrialbyjury.

4.6.Counterparts .ThisAgreementmaybeexecutedinseveralcounterparts,eachofwhichshallbedeemedanoriginalandallofwhichshallconstituteoneandthesameinstrument.TheexchangeofafullyexecutedAgreement(incounterpartsorotherwise)byallpartiesbyfacsimileorelectronictransmissionin.PDFformatshallbesufficienttobindthepartiestothetermsandconditionsofthisAgreement.

4.7.Entire Agreement .ThisAgreementconstitutestheentireagreementandsupersedesallprioragreementsandunderstandings,bothwrittenandoral,amongorbetweenanyofthepartieswithrespecttothesubjectmatterhereofandthereof.

4.8.Severability .AnytermorprovisionofthisAgreementthatisinvalidorunenforceableinanysituationinanyjurisdictionshallnotaffectthevalidityorenforceabilityoftheremainingtermsandprovisionsofthisAgreementorthevalidityorenforceabilityoftheoffendingtermorprovisioninanyothersituationorinanyotherjurisdiction.IfafinaljudgmentofacourtofcompetentjurisdictiondeclaresthatanytermorprovisionofthisAgreementisinvalidorunenforceable,thepartiesheretoagreethatthecourtmakingsuchdeterminationwillhavethepowertolimitsuchtermorprovision,todeletespecificwordsorphrasesortoreplacesuchtermorprovisionwithatermorprovisionthatisvalidandenforceableandthatcomesclosesttoexpressingtheintentionoftheinvalidorunenforceabletermorprovision,andthisAgreementshallbevalidandenforceableassomodified.Intheeventsuchcourtdoesnotexercisethepowergrantedtoitinthepriorsentence,thepartiesheretoagreetoreplacesuchinvalidorunenforceabletermorprovisionwithavalidandenforceabletermorprovisionthatwillachieve,totheextentpossible,theeconomic,businessandotherpurposesofsuchinvalidorunenforceabletermorprovision.

4.9.Specific Performance .Anyandallremedieshereinexpresslyconferreduponapartywillbedeemedcumulativewithandnotexclusiveofanyotherremedyconferredhereby,orbylaworequityuponsuchparty,andtheexercisebyapartyofanyoneremedywillnotprecludetheexerciseofanyotherremedy.ThepartiesheretoagreethatirreparabledamagewouldoccurintheeventthatanyoftheprovisionsofthisAgreementwerenotperformedinaccordancewiththeirspecifictermsorwereotherwisebreached.ItisaccordinglyagreedthatthepartiesshallbeentitledtoaninjunctionorinjunctionstopreventbreachesofthisAgreementandtoenforcespecificallythetermsandprovisionshereofinanyDelawareCourt,thisbeinginadditiontoanyotherremedytowhichtheyareentitledatlaworinequity,andeachofthepartiesheretowaivesanybond,suretyorothersecuritythatmightberequiredofanyotherpartywithrespectthereto.

4.10.Construction .

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(a) ForpurposesofthisAgreement,wheneverthecontextrequires:thesingularnumbershallincludetheplural,andviceversa;themasculinegendershallincludethefeminineandneutergenders;thefemininegendershallincludethemasculineandneutergenders;andtheneutergendershallincludemasculineandfemininegenders.

(b) ThepartiesheretoagreethatanyruleofconstructiontotheeffectthatambiguitiesaretoberesolvedagainstthedraftingpartyshallnotbeappliedintheconstructionorinterpretationofthisAgreement.

(c) AsusedinthisAgreement,thewords“include”and“including,”andvariationsthereof,shallnotbedeemedtobetermsoflimitation,butrathershallbedeemedtobefollowedbythewords“withoutlimitation.”Theword“or”whenusedinthisAgreementshallbedeemedtobeusedintheinclusivesenseof“and/or,”theword“any”whenusedinthisAgreementshallbedeemedtobeusedinthesenseof“anyandall,”andthewords“totheextent”whenusedinthisAgreementshallmeanthedegreetowhichasubjectorotheritemextendsandshallnotsimplymean“if.”AsusedinthisAgreement,thewords“hereof,”“herein,”“hereby,”“hereto,”and“hereunder”andwordsofsimilarimportwhenusedinthisAgreementshallrefertothisAgreementasawholeandnottoanyparticularprovisionofthisAgreement.

(d) Exceptasotherwiseindicated,allreferencesinthisAgreementto“Sections,”“Articles,”and“Schedules”areintendedtorefertoSectionsorArticlesofthisAgreementandSchedulestothisAgreement,respectively.

Thebold-facedheadingscontainedinthisAgreementareforconvenienceofreferenceonly,shallnotbedeemedtobeapartofthisAgreementandshallnotbereferredtoinconnectionwiththeconstructionorinterpretationofthisAgreement.

4.11.Further Assurances .Eachofthepartiesheretowillexecuteanddeliver,orcausetobeexecutedanddelivered,allfurtherdocumentsandinstrumentsandusetheirrespectivereasonablebesteffortstotake,orcausetobetaken,allactionsandtodo,orcausetobedone,allthingsnecessaryunderLegalRequirementstoperformtheirrespectiveobligationsasexpresslysetforthunderthisAgreement.

4.12.Capacity as Shareholder .TheShareholdersignsthisAgreementsolelyintheShareholder’scapacityasaShareholderofOpexa,andnotintheShareholder’scapacityasadirector,officeroremployeeofOpexaoranyofitsSubsidiariesorintheShareholder’scapacityasatrusteeorfiduciaryofanyemployeebenefitplanortrust.Notwithstandinganythinghereintothecontrary,nothinghereinshallinanywayrestrictadirectororofficerofOpexaintheexerciseofhisorherfiduciarydutiesasadirectororofficerofOpexaorinhisorhercapacityasatrusteeorfiduciaryofanyemployeebenefitplanortrustorpreventorbeconstruedtocreateanyobligationonthepartofanydirectororofficerofOpexaoranytrusteeorfiduciaryofanyemployeebenefitplanortrustfromtakinganyactioninhisorhercapacityassuchdirector,officer,trusteeorfiduciary.

4.13.No Agreement Until Executed .IrrespectiveofnegotiationsamongthepartiesortheexchangingofdraftsofthisAgreement,thisAgreementshallnotconstituteorbedeemedtoevidenceacontract,agreement,arrangementorunderstandingbetweenthepartiesheretounlessanduntil(a)theOpexaBoardofDirectorshasapproved,forpurposesofanyapplicableanti-takeoverlawsandregulations,andanyapplicableprovisionofOpexa’sorganizationaldocuments,theMerger,(b)theMergerAgreementisexecutedbyallpartiesthereto,and(c)thisAgreementisexecutedbyallpartieshereto.

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(SIGNATUREPAGEFOLLOWS)

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INWITNESSWHEREOF,thepartiesheretohavecausedthisAgreementtobedulyexecutedasofthedatefirstwrittenabove.

ACER THERAPEUTICS INC.

By:Name: ChrisSchellingTitle: PresidentandCEO

[Signature Page to Opexa Shareholder Support Agreement]

INWITNESSWHEREOF,thepartiesheretohavecausedthisAgreementtobedulyexecutedasofthedatefirstwrittenabove.

SHAREHOLDER

(Print Name of Shareholder)

(Signature)

(Name and Title of Signatory, if Signing on Behalf of an Entity)

(Address)

[Signature Page to Opexa Shareholder Support Agreement]

Schedule ANameofShareholder No.Shares

Exhibit 2.3

SUPPORT AGREEMENT

ThisSUPPORT AGREEMENT (this“Agreement”),datedasofJune30,2017,isbyandamongOpexaTherapeutics,Inc.(“Opexa”),andthePersonsetforthonScheduleAhereto(the“Stockholder”).

WHEREAS ,asofthedatehereof,theStockholderistheholderofthenumberofsharesofcommonstock,parvalue$0.0001pershare(the“CommonStock”)ofAcerTherapeutics,Inc.,aDelawarecorporation(“Acer”),theholderofthenumberofsharesofSeriesAPreferredStock,parvalue$0.0001pershare(the“SeriesAPreferredStock”),andtheholderofthenumberofsharesofSeriesBPreferredStock,parvalue$0.0001pershare(the“SeriesBPreferredStock”and,togetherwiththeSeriesAPreferredStock,the“PreferredStock”),ofAcersetforthoppositetheStockholder’snameonScheduleA(allsuchsharessetforthonScheduleA,togetherwithanysharesofCommonStockandPreferredStockofAcerthatarehereafterissuedtoorotherwiseacquiredorownedbytheStockholderpriortotheterminationofthisAgreementbeingreferredtohereinasthe“SubjectShares”);

WHEREAS ,Acer,OpexaMergerSub,Inc.,aDelawarecorporationandadirectwhollyownedsubsidiaryofOpexa(“MergerSub”)andOpexaproposetoenterintoanAgreementandPlanofMergerandReorganization,datedasofthedatehereof(the“MergerAgreement”),whichprovides,amongotherthings,forthemergerofMergerSubwithandintoAcer,withAcercontinuingasthesurvivingcorporation(the“Merger”),uponthetermsandsubjecttotheconditionssetforthintheMergerAgreement(capitalizedtermsusedbutnototherwisedefinedhereinshallhavetherespectivemeaningsascribedtosuchtermsintheMergerAgreement);and

WHEREAS ,asaconditiontoitswillingnesstoenterintotheMergerAgreement,OpexahasrequiredthattheStockholder,andasaninducementandinconsiderationtherefor,theStockholder(intheStockholder’scapacityasaholderoftheSubjectShares)hasagreedto,enterintothisAgreement.

NOW, THEREFORE ,inconsiderationoftheforegoingandtherespectiverepresentations,warranties,covenantsandagreementssetforthbelowandforothergoodandvaluableconsideration,thereceiptandsufficiencyofwhichareherebyacknowledged,thepartieshereto,intendingtobelegallybound,doherebyagreeasfollows:

ARTICLE I

VOTING AGREEMENT; GRANT OF PROXY

TheStockholderherebycovenantsandagreesthat:

1.1.Voting of Subject Shares .AteverymeetingoftheholdersofAcer’sCommonStockandPreferredStock(the“AcerStockholders”),howevercalled,andateveryadjournmentorpostponementthereof(orpursuanttoawrittenconsentifAcerStockholdersactbywrittenconsentinlieuofameeting),theStockholdershall,orshallcausetheholderofrecordonanyapplicablerecorddateto,bepresent(inpersonorbyproxy)andtovotetheStockholder’sSubjectShares(i)infavorof(A)adoptingtheMergerAgreementand(B)approvingtheMerger;and(ii)againstanyAcquisitionProposal.

1.2.No Inconsistent Arrangements .ExceptasprovidedhereunderorundertheMergerAgreement,theStockholdershallnot,directlyorindirectly,(a)createanyEncumbranceotherthanrestrictionsimposedbyLegalRequirementsorpursuanttothisAgreementonanySubjectShares,(b)transfer,sell,assign,giftorotherwisedisposeof(collectively,“Transfer”),orenterintoanycontract

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withrespecttoanyTransferoftheSubjectSharesoranyinteresttherein,(c)grantorpermitthegrantofanyproxy,powerofattorneyorotherauthorizationinorwithrespecttotheSubjectShares,(d)depositorpermitthedepositoftheSubjectSharesintoavotingtrustorenterintoavotingagreementorarrangementwithrespecttotheSubjectShares,or(e)takeanyactionthat,totheknowledgeoftheStockholder,wouldmakeanyrepresentationorwarrantyoftheStockholderhereinuntrueorincorrectinanymaterialrespect,orhavetheeffectofpreventingtheStockholderfromperformingitsobligationshereunder.Notwithstandingtheforegoing,(i)theStockholdermay(A)maketransfersoftheSubjectSharesascharitablegiftsordonations,(B)maketransfersordispositionsoftheSubjectSharestoanytrustforthedirectorindirectbenefitoftheStockholderortheimmediatefamilyoftheStockholder,(C)maketransfersordispositionsoftheSubjectSharesbywill,othertestamentarydocumentorintestatesuccessiontothelegalrepresentative,heir,beneficiaryoramemberoftheimmediatefamilyoftheStockholder,(D)maketransfersoftheSubjectSharestostockholders,directorindirectaffiliates(withinthemeaningsetforthinRule405undertheSecuritiesActof1933,asamended),currentorformerpartners(generalorlimited),membersormanagersoftheStockholder,asapplicable,ortotheestatesofanysuchstockholders,affiliates,partners,membersormanagers,ortoanothercorporation,partnership,limitedliabilitycompanyorotherbusinessentitythatcontrols,iscontrolledbyorisundercommoncontrolwiththeStockholder,(E)maketransfersoftheSubjectSharesthatoccurbyoperationoflawpursuanttoaqualifieddomesticorderorinconnectionwithadivorcesettlement,(F)maketransfersordispositionsoftheSubjectSharesnotinvolvingachangeinbeneficialownership,(G)iftheStockholderisatrust,maketransfersordispositionsoftheSubjectSharestoanybeneficiaryoftheStockholderortheestateofanysuchbeneficiary,providedthat,ineachcase,thetransfereeagreesinwritingtobeboundbythetermsandconditionsofthisAgreementandeithertheStockholderorthetransfereeprovidesOpexawithacopyofsuchagreementpromptlyuponconsummationofanysuchTransferand(ii)theStockholdermaytakeallactionsreasonablynecessarytoconsummatetheContemplatedTransactions,includingeffectingthePreferredStockConversion.

1.3.No Exercise of Appraisal Rights; Waivers .TheStockholderhereby(a)waivesandagreesnottoexerciseanydissenters’orappraisalrights,orothersimilarrights,withrespecttoanySubjectSharesthatmayariseinconnectionwiththeContemplatedTransactionsand(b)agreesthatitwillnotbring,commence,institute,maintain,prosecute,participateinorvoluntarilyaidanyaction,claim,suitorcauseofaction,inlaworinequity,inanycourtorbeforeanyGovernmentalBody,which(i)challengesthevalidityoforseekstoenjointheoperationofanyprovisionofthisAgreementor(ii)allegesthattheexecutionanddeliveryofthisAgreementbytheStockholder,ortheapprovaloftheMergerAgreementbytheAcerBoardofDirectors,breachesanyfiduciarydutyoftheAcerBoardofDirectorsoranymemberthereof;provided , that theStockholdermaydefendagainst,contestorsettleanysuchaction,claim,suitorcauseofactionbroughtagainsttheStockholderthatrelatessolelytotheStockholder’scapacityasadirector,officerorsecurityholderofAcer.

1.4.Documentation and Information .TheStockholdershallpermitandherebyauthorizesOpexaandAcertopublishanddiscloseinalldocumentsandschedulesfiledwiththeSEC,andanyotherdisclosuredocumentthatOpexaorAcerreasonablydeterminestoberequiredbyapplicablelawinconnectionwiththeMergerandanytransactionscontemplatedbytheMergerAgreement,theStockholder’sidentityandownershipoftheSubjectSharesandthenatureoftheStockholder’scommitmentsandobligationsunderthisAgreement;providedthatOpexaorAcer,asthecasemaybe,shallaffordtheStockholderreasonableadvancednoticetoreviewandcommentonsuchdisclosure.Acerisanintendedthird-partybeneficiaryofthisSection1.4.

1.5.Irrevocable Proxy . TheStockholderherebyrevokes(oragreestocausetoberevoked)anyproxiesthattheStockholderhasheretoforegrantedwithrespecttotheSubjectShares.TheStockholderherebyirrevocablyappointsOpexaasattorney-in-factandproxyforandonbehalfoftheStockholder,for

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andinthename,placeandsteadoftheStockholder,to:(a)attendanyandallmeetingsofAcerStockholdersheldforthemattersaddressedinSection1.1,(b)vote,expressconsentordissentorissueinstructionstotherecordholdertovotetheSubjectSharessolelyinfurtheranceoftheprovisionsofSection1.1atanyandallmeetingsofAcerStockholdersorinconnectionwithanyactionsoughttobetakenbywrittenconsentofAcerStockholderswithoutameetingand(c)grantorwithhold,orissueinstructionstotherecordholdertograntorwithhold,consistentwiththeprovisionsofSection1.1,allwrittenconsentswithrespecttotheSubjectSharesatanyandallmeetingsofAcerStockholdersorinconnectionwithanyactionsoughttobetakenbywrittenconsentofAcerStockholderswithoutameeting,inanycasesolelyinfurtheranceoftheprovisionsofSection1.1.OpexaagreesnottoexercisetheproxygrantedhereinforanypurposeotherthanthepurposesdescribedinthisAgreement.Theforegoingproxyshallbedeemedtobeaproxycoupledwithaninterest,isirrevocable(andassuchshallsurviveandnotbeaffectedbythedeath,incapacity,mentalillnessorinsanityoftheStockholder,asapplicable)untiltheterminationoftheMergerAgreementandshallnotbeterminatedbyoperationoflaworupontheoccurrenceofanyothereventotherthantheterminationofthisAgreementpursuanttoSection4.2.TheStockholderauthorizessuchattorneyandproxytosubstituteanyotherPersontoacthereunder,torevokeanysubstitutionandtofilethisproxyandanysubstitutionorrevocationwiththeSecretaryofAcer.TheStockholderherebyaffirmsthattheproxysetforthinthisSection1.5isgiveninconnectionwithandgrantedinconsiderationofandasaninducementtoOpexaandMergerSubtoenterintotheMergerAgreementandthatsuchproxyisgiventosecuretheobligationsoftheStockholderunderSection1.1.TheproxysetforthinthisSection1.5isexecutedandintendedtobeirrevocable,subject,however,toitsautomaticterminationupontheterminationofthisAgreementpursuanttoSection4.2.WithrespecttoanySubjectSharesthatareownedbeneficiallybytheStockholderbutarenotheldofrecordbytheStockholder,theStockholdershalltakeallactionnecessarytocausetherecordholderofsuchSubjectSharestogranttheirrevocableproxyandtakeallotheractionsprovidedforinthisSection1.5withrespecttosuchSubjectShares.

1.6.No Solicitation of Transactions .TheStockholdershallnotknowingly,directlyorindirectly,throughanyofficer,director,agentorotherwise,(a)solicit,initiate,respondtoorknowinglytakeanyactiontofacilitateorencourageanyinquiriesorthecommunication,making,submissionorannouncementofanyAcquisitionProposalorAcquisitionInquiryortakeanyactionthatcouldreasonablybeexpectedtoleadtoanAcquisitionProposalorAcquisitionInquiry;(b)enterintoorparticipateinanydiscussionsornegotiationswithanyPersonwithrespecttoanyAcquisitionProposalorAcquisitionInquiry;(c)furnishanyinformationregardingsuchpartytoanyPersoninconnectionwith,inresponseto,relatingtoorforthepurposeofassistingwithorfacilitatinganAcquisitionProposalorAcquisitionInquiry;or(d)approve,endorseorrecommendanyAcquisitionProposal.TheStockholderherebyrepresentsandwarrantsthathe,sheorithasreadSection4.5oftheMergerAgreementandagreesnottoengageinanyactionsprohibitedthereby.

1.7.No Ownership Interest .NothingcontainedinthisAgreementwillbedeemedtovestinOpexaanydirectorindirectownershiporincidentsofownershipoforwithrespecttotheSubjectShares.Allrights,ownershipandeconomicbenefitsofandrelatingtotheSubjectShareswillremainandbelongtotheStockholder,andOpexawillhavenoauthoritytomanage,direct,superintend,restrict,regulate,governoradministeranyofthepoliciesoroperationsofAcerorexerciseanypowerorauthoritytodirecttheStockholderinthevotingofanyoftheSubjectShares,exceptasotherwiseexpresslyprovidedhereinwithrespecttotheSubjectSharesandexceptasotherwiseexpresslyprovidedintheMergerAgreement.

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ARTICLE II

REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDER

TheStockholderrepresentsandwarrantstoOpexathat:

2.1.Organization; Authorization ; Binding Agreement .TheStockholder,ifnotanaturalperson,isdulyincorporatedororganized,asapplicable,validlyexistingandingoodstandingunderthelawsofitsjurisdictionofincorporationororganization.TheStockholderhasfulllegalcapacityandpower,rightandauthoritytoexecuteanddeliverthisAgreementandtoperformhis,heroritsobligationshereunderandtoconsummatethetransactionscontemplatedhereby.ThisAgreementhasbeendulyandvalidlyexecutedanddeliveredbytheStockholder,andconstitutesavalidandbindingobligationoftheStockholderenforceableagainsttheStockholderinaccordancewithitsterms,subjectto(a)lawsofgeneralapplicationrelatingtobankruptcy,insolvencyandthereliefofdebtorsand(b)lawsofgeneralapplicationrelatingtobankruptcy,insolvency,thereliefofdebtors,fraudulenttransfer,reorganization,moratoriumandothersimilarlawsofgeneralapplicabilityrelatingtooraffectingcreditor’srights(the“EnforceabilityExceptions”).

2.2.Ownership of Subject Shares; Total Shares .TheStockholderistherecordorbeneficialowner(asdefinedinRule13d-3undertheExchangeAct)oftheSubjectSharesandhasgoodandmarketabletitletotheSubjectSharesfreeandclearofanyEncumbrances(includinganyrestrictionontherighttovoteorotherwisetransfertheSubjectShares),except(a)asprovidedhereunder,(b)pursuanttoanyapplicablerestrictionsontransferundertheSecuritiesAct,(c)subjecttoanyriskofforfeiturewithrespecttoanysharesofCommonStockgrantedtotheStockholderunderanemployeebenefitplanofAcerand(d)asprovidedinthebylawsofAcerorintheInvestorAgreements.TheSubjectShareslistedonScheduleAoppositetheStockholder’snameconstituteallofthesharesofCommonStockandPreferredStockofAcerownedbytheStockholderasofthedatehereof.ExceptpursuanttotheInvestorAgreementsorAcer’sbylaws,noPersonhasanycontractualorotherrightorobligationtopurchaseorotherwiseacquireanyoftheSubjectShares.

2.3.Voting Power .TheStockholderhasfullvotingpower,withrespecttotheStockholder’sSubjectShares,andfullpowerofdisposition,fullpowertoissueinstructionswithrespecttothematterssetforthhereinandfullpowertoagreetoallofthematterssetforthinthisAgreement,ineachcasewithrespecttoalloftheSubjectShares.NoneoftheStockholder’sSubjectSharesaresubjecttoanyproxy,votingtrustorotheragreementorarrangementwithrespecttothevotingoftheSubjectShares,except(a)asprovidedintheInvestorAgreementsand(b)asprovidedhereunder.

2.4.Reliance .TheStockholderhashadtheopportunitytoreviewtheMergerAgreementandthisAgreementwithcounseloftheStockholder’sownchoosing.TheStockholderunderstandsandacknowledgesthatOpexaandMergerSubareenteringintotheMergerAgreementinrelianceupontheStockholder’sexecution,deliveryandperformanceofthisAgreement.

2.5.Absence of Litigation .WithrespecttotheStockholder,asofthedatehereof,thereisnoaction,suit,investigationorproceedingpendingagainst,or,totheknowledgeoftheStockholder,threatenedinwritingagainst,theStockholderoranyoftheStockholder’spropertiesorassets(includingtheSubjectShares)thatcouldreasonablybeexpectedtoprevent,delayorimpairtheabilityoftheStockholdertoperformitsobligationshereunderortoconsummatethetransactionscontemplatedhereby.

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ARTICLE III

REPRESENTATIONS AND WARRANTIES OF OPEXA

OpexarepresentsandwarrantstotheStockholderthat:

3.1.Organization; Authorization .Opexaisacorporationdulyincorporated,validlyexistingandingoodstandingunderthelawsoftheStateofTexas.TheconsummationofthetransactionscontemplatedherebyiswithinOpexa’scorporatepowersandhasbeendulyauthorizedbyallnecessarycorporateactionsonthepartofOpexa.Opexahasfullpowerandauthoritytoexecute,deliverandperformthisAgreement.

3.2.Binding Agreement .ThisAgreementhasbeendulyauthorized,executedanddeliveredbyOpexaandconstitutesavalidandbindingobligationofOpexaenforceableagainstOpexainaccordancewithitsterms,subjecttotheEnforceabilityExceptions.

ARTICLE IV

MISCELLANEOUS

4.1.Notices .Allnotices,requestsandothercommunicationstoeitherpartyhereundershallbeinwriting(includingfacsimiletransmissionorelectronicmail)andshallbegiven,(a)iftoOpexa,inaccordancewiththeprovisionsoftheMergerAgreementand(b)iftotheStockholder,totheStockholder’saddress,electronicmailaddressorfacsimilenumbersetforthonasignaturepagehereto,ortosuchotheraddress,electronicaddressorfacsimilenumberastheStockholdermayhereafterspecifyinwritingtoOpexaforthepurposebynoticetoOpexa.

4.2.Termination .ThisAgreementshallterminateautomatically,withoutanynoticeorotheractionbyanyPerson,upontheearlierof(a)theterminationoftheMergerAgreementinaccordancewithitstermsand(b)theEffectiveTime.UponterminationofthisAgreement,neitherpartyshallhaveanyfurtherobligationsorliabilitiesunderthisAgreement;provided, however, that(i)nothingsetforthinthisSection4.2shallrelieveeitherpartyfromliabilityforanybreachofthisAgreementpriortoterminationhereof,and(ii)theprovisionsofthisArticleIVshallsurviveanyterminationofthisAgreement.

4.3.Amendments and Waivers .AnyprovisionofthisAgreementmaybeamendedorwaivedifsuchamendmentorwaiverisinwritingandissigned,inthecaseofanamendment,bytheStockholderandOpexa,inthecaseofawaiver,bythepartyagainstwhomthewaiveristobeeffective.Nofailureordelaybyeitherpartyinexercisinganyright,powerorprivilegehereundershalloperateasawaiverthereofnorshallanysingleorpartialexercisethereofprecludeanyotherorfurtherexercisethereofortheexerciseofanyotherright,powerorprivilege.

4.4.Binding Effect; Benefit; Assignment .TheprovisionsofthisAgreementshallbebindinguponandshallinuretothebenefitofthepartiesheretoandtheirrespectivesuccessorsandassigns.ExceptassetforthinSection1.4,noprovisionofthisAgreementisintendedtoconferanyrights,benefits,remedies,obligationsorliabilitieshereunderuponanypersonotherthanthepartiesheretoandtheirrespectivesuccessorsandassigns.Neitherpartymayassign,delegateorotherwisetransferanyofitsrightsorobligationsunderthisAgreementwithouttheconsentoftheotherpartyhereto,exceptthatOpexamaytransferorassignitsrightsandobligationsunderthisAgreement,inwholeorfromtimetotimeinpart,tooneormoreofitsAffiliatesatanytime;provided,thatsuchtransferorassignmentshallnotrelieveOpexaofanyofitsobligationshereunder.

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4.5.Governing Law; Jurisdiction .ThisAgreementshallbegovernedby,andconstruedinaccordancewith,thelawsoftheStateofDelaware,regardlessofthelawsthatmightotherwisegovernunderapplicableprinciplesofconflictsoflaws.InanyactionorsuitbetweenanyofthepartiesarisingoutoforrelatingtothisAgreement:(a)eachofthepartiesirrevocablyandunconditionallyconsentsandsubmitstotheexclusivejurisdictionandvenueoftheDelawareCourtofChancery,orifsuchcourtdoesnothaveproperjurisdiction,thenthefederalcourtslocatedintheStateofDelaware,andappellatecourtstherefrom,(collectively,the“DelawareCourts”);and(b)eachofthepartiesirrevocablywaivestherighttotrialbyjury.

4.6.Counterparts .ThisAgreementmaybeexecutedinseveralcounterparts,eachofwhichshallbedeemedanoriginalandallofwhichshallconstituteoneandthesameinstrument.TheexchangeofafullyexecutedAgreement(incounterpartsorotherwise)byallpartiesbyfacsimileorelectronictransmissionin.PDFformatshallbesufficienttobindthepartiestothetermsandconditionsofthisAgreement.

4.7.Entire Agreement .ThisAgreementconstitutestheentireagreementandsupersedesallprioragreementsandunderstandings,bothwrittenandoral,amongorbetweenanyofthepartieswithrespecttothesubjectmatterhereofandthereof.

4.8.Severability .AnytermorprovisionofthisAgreementthatisinvalidorunenforceableinanysituationinanyjurisdictionshallnotaffectthevalidityorenforceabilityoftheremainingtermsandprovisionsofthisAgreementorthevalidityorenforceabilityoftheoffendingtermorprovisioninanyothersituationorinanyotherjurisdiction.IfafinaljudgmentofacourtofcompetentjurisdictiondeclaresthatanytermorprovisionofthisAgreementisinvalidorunenforceable,thepartiesheretoagreethatthecourtmakingsuchdeterminationwillhavethepowertolimitsuchtermorprovision,todeletespecificwordsorphrasesortoreplacesuchtermorprovisionwithatermorprovisionthatisvalidandenforceableandthatcomesclosesttoexpressingtheintentionoftheinvalidorunenforceabletermorprovision,andthisAgreementshallbevalidandenforceableassomodified.Intheeventsuchcourtdoesnotexercisethepowergrantedtoitinthepriorsentence,thepartiesheretoagreetoreplacesuchinvalidorunenforceabletermorprovisionwithavalidandenforceabletermorprovisionthatwillachieve,totheextentpossible,theeconomic,businessandotherpurposesofsuchinvalidorunenforceabletermorprovision.

4.9.Specific Performance .Anyandallremedieshereinexpresslyconferreduponapartywillbedeemedcumulativewithandnotexclusiveofanyotherremedyconferredhereby,orbylaworequityuponsuchparty,andtheexercisebyapartyofanyoneremedywillnotprecludetheexerciseofanyotherremedy.ThepartiesheretoagreethatirreparabledamagewouldoccurintheeventthatanyoftheprovisionsofthisAgreementwerenotperformedinaccordancewiththeirspecifictermsorwereotherwisebreached.ItisaccordinglyagreedthatthepartiesshallbeentitledtoaninjunctionorinjunctionstopreventbreachesofthisAgreementandtoenforcespecificallythetermsandprovisionshereofinanyDelawareCourt,thisbeinginadditiontoanyotherremedytowhichtheyareentitledatlaworinequity,andeachofthepartiesheretowaivesanybond,suretyorothersecuritythatmightberequiredofanyotherpartywithrespectthereto.

4.10.Construction .

(a) ForpurposesofthisAgreement,wheneverthecontextrequires:thesingularnumbershallincludetheplural,andviceversa;themasculinegendershallincludethefeminineandneutergenders;thefemininegendershallincludethemasculineandneutergenders;andtheneutergendershallincludemasculineandfemininegenders.

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(b) ThepartiesheretoagreethatanyruleofconstructiontotheeffectthatambiguitiesaretoberesolvedagainstthedraftingpartyshallnotbeappliedintheconstructionorinterpretationofthisAgreement.

(c) AsusedinthisAgreement,thewords“include”and“including,”andvariationsthereof,shallnotbedeemedtobetermsoflimitation,butrathershallbedeemedtobefollowedbythewords“withoutlimitation.”Theword“or”whenusedinthisAgreementshallbedeemedtobeusedintheinclusivesenseof“and/or,”theword“any”whenusedinthisAgreementshallbedeemedtobeusedinthesenseof“anyandall,”andthewords“totheextent”whenusedinthisAgreementshallmeanthedegreetowhichasubjectorotheritemextendsandshallnotsimplymean“if.”AsusedinthisAgreement,thewords“hereof,”“herein,”“hereby,”“hereto,”and“hereunder”andwordsofsimilarimportwhenusedinthisAgreementshallrefertothisAgreementasawholeandnottoanyparticularprovisionofthisAgreement.

(d) Exceptasotherwiseindicated,allreferencesinthisAgreementto“Sections,”“Articles,”and“Schedules”areintendedtorefertoSectionsorArticlesofthisAgreementandSchedulestothisAgreement,respectively.

(e) Thebold-facedheadingscontainedinthisAgreementareforconvenienceofreferenceonly,shallnotbedeemedtobeapartofthisAgreementandshallnotbereferredtoinconnectionwiththeconstructionorinterpretationofthisAgreement.

4.11.Further Assurances .Eachofthepartiesheretowillexecuteanddeliver,orcausetobeexecutedanddelivered,allfurtherdocumentsandinstrumentsandusetheirrespectivereasonablebesteffortstotake,orcausetobetaken,allactionsandtodo,orcausetobedone,allthingsnecessaryunderLegalRequirementstoperformtheirrespectiveobligationsasexpresslysetforthunderthisAgreement.

4.12.Capacity as Stockholder .TheStockholdersignsthisAgreementsolelyintheStockholder’scapacityasaStockholderofAcer,andnotintheStockholder’scapacityasadirector,officeroremployeeofAceroranyofitsSubsidiariesorintheStockholder’scapacityasatrusteeorfiduciaryofanyemployeebenefitplanortrust.Notwithstandinganythinghereintothecontrary,nothinghereinshallinanywayrestrictadirectororofficerofAcerintheexerciseofhisorherfiduciarydutiesasadirectororofficerofAcerorinhisorhercapacityasatrusteeorfiduciaryofanyemployeebenefitplanortrustorpreventorbeconstruedtocreateanyobligationonthepartofanydirectororofficerofAceroranytrusteeorfiduciaryofanyemployeebenefitplanortrustfromtakinganyactioninhisorhercapacityassuchdirector,officer,trusteeorfiduciary.

4.13.No Agreement Until Executed .IrrespectiveofnegotiationsamongthepartiesortheexchangingofdraftsofthisAgreement,thisAgreementshallnotconstituteorbedeemedtoevidenceacontract,agreement,arrangementorunderstandingbetweenthepartiesheretounlessanduntil(a)theAcerBoardofDirectorshasapproved,forpurposesofanyapplicableanti-takeoverlawsandregulations,andanyapplicableprovisionofAcer’sorganizationaldocuments,theMerger,(b)theMergerAgreementisexecutedbyallpartiesthereto,and(c)thisAgreementisexecutedbyallpartieshereto.

(SIGNATUREPAGEFOLLOWS)

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INWITNESSWHEREOF,thepartiesheretohavecausedthisAgreementtobedulyexecutedasofthedatefirstwrittenabove.

OPEXA THERAPEUTICS, INC.

By:Name: NeilK.Warma

Title:

President,ChiefExecutiveOfficerandActingChiefFinancialOfficer

[Signature Page to Acer Stockholder Support Agreement]

INWITNESSWHEREOF,thepartiesheretohavecausedthisAgreementtobedulyexecutedasofthedatefirstwrittenabove.

STOCKHOLDER

(Print Name of Stockholder)

(Signature)

(Name and Title of Signatory, if Signing on Behalf of an Entity)

(Address)

[Signature Page to Acer Stockholder Support Agreement]

Schedule A

Name of Stockholder

No. Shares ofCommon

Stock

No. Shares ofSeries A

Preferred Stock

No. Shares ofSeries B

Preferred Stock

Exhibit 99.1

Acer Therapeutics and Opexa Therapeutics Sign Merger Agreement

-Merger to create a pre-NDA-stage, NASDAQ-listed, pharmaceutical company focused on the development and commercialization of therapies for serious rarediseases with critical unmet medical need-

-Concurrent financing of $15.7 million from Acer investor syndicate-

-Acer plans to file a NDA for its lead product, EDSIVO™, for the treatment of vascular Ehlers-Danlos Syndrome (vEDS) in the first half of 2018-

July 3, 2017

CAMBRIDGE , MA and THE WOODLANDS , TX –OpexaTherapeutics,Inc.(Nasdaq:OPXA)(“Opexa”)andAcerTherapeuticsInc.(“Acer”),aprivately-heldpharmaceuticalcompany,todayannouncedthattheyhaveenteredintoadefinitivemergeragreementunderwhichthestockholdersofAcer(includinginvestorsinafinancingthatwillcloseconcurrentlywiththemerger)arecurrentlyestimatedtobecomeholdersofapproximately88.8%ofOpexa’soutstandingcommonstockonaproformabasis,withcurrentOpexashareholdersexpectedtoowntheremaining11.2%.Theproposedmergerremainssubjecttocertainconditions,includingapprovalbyOpexa’sshareholdersandAcer’sstockholders.

Inconjunctionwiththeproposedmerger,aninvestorsyndicateledbyTVMCapitalLifeSciencesandcomprisedofexistingAcerinvestorsandnewinvestorshascommittedtoinvestapproximately$15.7millioninAcer(includingthroughaconversionofapproximately$5.7millioninoutstandingconvertiblenotes)immediatelypriortoclosingoftheproposedmerger.

“Acer’sgoalistobecomealeadingpharmaceuticalcompanythatacquires,developsandcommercializestherapiesforthetreatmentofpatientswithseriousrarediseaseswithcriticalunmetmedicalneed,”saidChrisSchelling,ChiefExecutiveOfficerandfounderofAcer.“WehavecommittedsignificantresourcestorapidlyadvanceourleadcandidateEDSIVO™,apotentiallife-savingtherapyforpatientswithvEDS.WebelievethattheproceedsfromtheconcurrentfinancingwillallowustoadvanceEDSIVO™throughNDAsubmissionwiththeFDAinthefirsthalfof2018.Asapubliccompany,welookforwardtoengagingwithabroaderpoolofinvestorsasweseektoadvanceandexpandourpipelineandmakemultipleproductsavailabletopatientsoverthenextseveralyears.”

NeilK.Warma,Opexa’sPresidentandChiefExecutiveOfficeradded,“WehavechosentocombinewithAcerfollowinganextensivereviewofstrategicalternatives.Acer’sleadasset,EDSIVO™,couldbeonthemarketwithinthenexttwoyears.Thisfactor,togetherwithAcer’sstrategicvision,pipeline,therecentlysecuredfinancingandAcer’sstrongmanagementteam,providesOpexashareholderswithanopportunityforgrowthinthevalueoftheirshares.”

About the Proposed Merger

ExistingstockholdersofAcer,aswellasinvestorsinAcer’sconcurrentfinancing,willreceivenewlyissuedsharesofOpexacommonstockinconnectionwiththeproposedmerger.Onaproformabasisforthecombinedcompany,following

theclosingoftheproposedmerger,(a)currentOpexashareholdersareexpectedtoownapproximately11.2%,(b)currentAcerstockholdersareexpectedtoownapproximately63.8%(excludingsharesissuedtothemintheconcurrentfinancing),and(c)theinvestorsparticipatingintheconcurrentfinancingareexpectedtoownapproximately25%(excludingsharespreviouslyheldbythem).

Theproposedmergerhasbeenunanimouslyapprovedbytheboardsofdirectorsofbothcompanies,andamajorityofAcer’sstockholdershaveagreedtovoteinfavorofthetransaction.Theproposedmergerisexpectedtocloseduringthethirdquarterof2017,subjecttotheapprovalofthestockholdersofAcerandtheshareholdersofOpexaandothercustomaryclosingconditions.Themergeragreementcontainsfurtherdetailswithrespecttotheproposedmerger.Ifthetransactionisconsummated,Opexa’snamewillbechangedtoAcerTherapeuticsInc.,andOpexaintendstoapplytochangeitstickersymbolontheNASDAQCapitalMarketto“ACER.”

ThedirectorsandthesoleexecutiveofficerofOpexawillresignfromtheirpositionswithOpexaupontheclosingoftheproposedmerger,andthecombinedcompanywillbeundertheleadershipofAcer’scurrentexecutivemanagementteamwithChrisSchellingservingasPresidentandChiefExecutiveOfficer.Followingtheclosingoftheproposedmerger,theboardofdirectorsofthecombinedcompanyisexpectedtoconsistof7members,allofwhomwillbedesignatedbyAcer.ThecorporateheadquarterswillbelocatedinCambridge,Massachusetts.

PiperJaffray&Co.isactingasplacementagentforAcerintheconcurrentfinancing.PillsburyWinthropShawPittmanLLPservedaslegalcounseltoOpexaandFoleyHoagLLPservedaslegalcounseltoAcer.

About Acer Therapeutics Inc.

Acer,headquarteredinCambridge,MA,isapharmaceuticalcompanythatacquires,developsandintendstocommercializetherapiesforpatientswithseriousrarediseaseswithcriticalunmetmedicalneed.Acer’slate-stageclinicalpipelineincludestwocandidatesforseveregeneticdisordersforwhichtherearefewornoFDA-approvedtreatments:EDSIVO™(celiprolol)forvEDS,andACER-001(afullytaste-masked,immediatereleaseformulationofsodiumphenylbutyrate)forureacycledisorders(UCD)andMapleSyrupUrineDisease(MSUD).TherearenoFDA-approveddrugsforvEDSandMSUDandlimitedoptionsforUCD,whichcollectivelyimpactmorethan4,000patientsintheUnitedStates.Acer’sproductshaveclinicalproof-of-conceptandmechanisticdifferentiation,andAcerintendstoseekapprovalforthemintheU.S.byusingtheregulatorypathwayestablishedundersection505(b)(2)oftheFederalFood,Drug,andCosmeticAct,orFFDCA,thatallowsanapplicanttorelyforapprovalatleastinpartonthird-partydata,whichisexpectedtoexpeditethepreparation,submission,andapprovalofamarketingapplication.

Formoreinformation,visitwww.acertx.com.

About Opexa Therapeutics, Inc.

OpexaTherapeuticsisabiopharmaceuticalcompanythathashistoricallyfocusedondevelopingpersonalizedimmunotherapieswiththepotentialtotreatmajorillnesses,includingmultiplesclerosisaswellasotherautoimmunediseasessuchasneuromyelitisoptica.ThesetherapiesarebasedonOpexa’sproprietaryT-celltechnology.

Safe Harbor Statement

Additional Information about the Proposed Merger and Where to Find It

Inconnectionwiththeproposedmerger,OpexaandAcerintendtofilerelevantmaterialswiththeSecuritiesandExchangeCommission,ortheSEC,includingaregistrationstatementonFormS-4thatwillcontainaproxystatement/prospectus/informationstatement.InvestorsandsecurityholdersofOpexaandAcerareurgedtoreadthesematerialswhentheybecomeavailablebecausetheywillcontainimportantinformationaboutOpexa,Acerandtheproposedmerger.Theproxystatement/prospectus/informationstatementandotherrelevantmaterials(whentheybecomeavailable),andanyotherdocumentsfiledbyOpexawiththeSEC,maybeobtainedfreeofchargeattheSECwebsiteatwww.sec.gov .Inaddition,investorsandsecurityholdersmayobtainfreecopiesofthedocumentsfiledwiththeSECbyOpexabydirectingawrittenrequestto:OpexaTherapeutics,Inc.,2635TechnologyForestBlvd.,TheWoodlands,TX77381,Attention:InvestorRelations.Investorsandsecurityholdersareurgedtoreadtheproxystatement/prospectus/

informationstatementandtheotherrelevantmaterialswhentheybecomeavailablebeforemakinganyvotingorinvestmentdecisionwithrespecttotheproposedmerger.

This communication shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities, nor shall there beany sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws ofany such jurisdiction. No offering of securities in connection with the proposed merger shall be made except by means of a prospectus meeting the requirements ofSection 10 of the Securities Act of 1933, as amended.

Participants in the Solicitation

OpexaanditsdirectorsandsoleexecutiveofficerandAceranditsdirectorsandexecutiveofficersmaybedeemedtobeparticipantsinthesolicitationofproxiesfromtheshareholdersofOpexainconnectionwiththeproposedtransaction.Informationregardingthespecialinterestsofthesedirectorsandexecutiveofficersintheproposedmergerwillbeincludedintheproxystatement/prospectus/informationstatementreferredtoabove.AdditionalinformationregardingthedirectorsandthesoleexecutiveofficerofOpexaisalsoincludedinOpexa’sAnnualReportonForm10-KfortheyearendedDecember31,2016andtheproxystatementforOpexa’s2016AnnualMeetingofShareholders.ThesedocumentsareavailablefreeofchargeattheSEC’swebsite(www.sec.gov )andfromInvestorRelationsatOpexaattheaddressdescribedabove.

Forward-Looking Statements

This press release contains “forward-looking statements” that involve substantial risks and uncertainties for purposes of the safe harbor provided by the PrivateSecurities Litigation Reform Act of 1995. All statements, other than statements of historical facts, included in this press release regarding strategy, futureoperations, future financial position, future revenue, projected expenses, prospects, plans and objectives of management are forward-looking statements. Examplesof such statements include, but are not limited to, statements relating to the structure, timing and completion of the proposed merger or financing; Opexa’scontinued listing on the NASDAQ Capital Market until closing of the proposed merger; the combined company’s listing on the NASDAQ Capital Market afterclosing of the proposed merger; expectations regarding the capitalization, resources and ownership structure of the combined company; the potential for Edsivo™(celiprolol) and ACER-001 to safely and effectively target diseases; the adequacy of the combined company’s capital to support its future operations and its abilityto successfully initiate and complete clinical trials; the nature, strategy and focus of the combined company; the development and commercial potential of anyproduct candidates of the combined company; the executive and board structure of the combined company; and expectations regarding voting by Opexa’sshareholders and Acer’s stockholders. Opexa and/or Acer may not actually achieve the plans, carry out the intentions or meet the expectations or projectionsdisclosed in the forward-looking statements and you should not place undue reliance on these forward-looking statements. Such statements are based onmanagement’s current expectations and involve risks and uncertainties. Actual results and performance could differ materially from those projected in theforward-looking statements as a result of many factors, including, without limitation, risks and uncertainties associated with securityholder approval of and theability to consummate the proposed merger through the process being conducted by Opexa and Acer, the ability to project future cash utilization and reservesneeded for contingent future liabilities and business operations, the availability of sufficient resources of the combined company to meet its business objectives andoperational requirements, the fact that the results of earlier studies and trials may not be predictive of future clinical trial results, the protection and marketexclusivity provided by Acer’s intellectual property, risks related to the drug discovery and the regulatory approval process and the impact of competitive productsand technological changes. Opexa and Acer each disclaims any intent or obligation to update these forward-looking statements to reflect events or circumstancesthat exist after the date on which they were made.

AcerInvestorContact:HarryPalminTel:(844)902-6100hpalmin@acertx.com

OpexaInvestorContact:NeilK.Warma

Tel:(281)881-6527nwarma@opexatherapeutics.com