Alkylating agents Platinating agents Antimetabolites Topoisomerase inhibitors

www.rwww.radbioladbiol.ucla.edu.ucla.edu

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Interaction of RT with CT and Interaction of RT with CT and other Agentsother Agents

Bill McBrideBill McBrideDept. Radiation OncologyDept. Radiation Oncology

David Geffen School MedicineDavid Geffen School MedicineUCLA, Los Angeles, Ca.UCLA, Los Angeles, Ca.

[email protected]@mednet.ucla.edu


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• Alkylating agentsAlkylating agents• Platinating agentsPlatinating agents• AntimetabolitesAntimetabolites• Topoisomerase inhibitorsTopoisomerase inhibitors• Anti-microtubular agentsAnti-microtubular agents• MiscellaneousMiscellaneous

Classes of Chemotherapy AgentsClasses of Chemotherapy Agents


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• Alkylating agentsAlkylating agents• Nitrogen mustard derivatives: Nitrogen mustard derivatives: cyclophosphamide, chlorambucil, cyclophosphamide, chlorambucil,

melphalan, ifosfamide, mechlorethaminemelphalan, ifosfamide, mechlorethamine

• Ethylenimines: Ethylenimines: Thiotepa and HexamethylmelamineThiotepa and Hexamethylmelamine

• Nitrosoureas: Nitrosoureas: BCNU (carmustine), CCNU (lomustine), StreptozocinBCNU (carmustine), CCNU (lomustine), Streptozocin

• Alkylsulfonates: Alkylsulfonates: BusulfanBusulfan

• Hydrazines and Triazines: Hydrazines and Triazines: altretamine, procarbazine, dacarbazine, altretamine, procarbazine, dacarbazine, temodartemodar

• Highly reactive alkyl groups (e.g. —CHHighly reactive alkyl groups (e.g. —CH22Cl) covalently bind Cl) covalently bind

to intracellular macromolecule, such as DNAto intracellular macromolecule, such as DNA• Bifunctional crosslink are more effective (interstrand DNA Bifunctional crosslink are more effective (interstrand DNA

crosslinks)crosslinks)• Limited cell cycle specificity, carcinogenicLimited cell cycle specificity, carcinogenic

Classes of AgentsClasses of Agents


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• Platinating agentsPlatinating agents• Cisplatin, Carboplatin, oxiplatinCisplatin, Carboplatin, oxiplatin• Exist in 2+ oxidation state with 4 groups that interact with Exist in 2+ oxidation state with 4 groups that interact with

DNA (95% intrastrand 5% interstrand cross-linkages)DNA (95% intrastrand 5% interstrand cross-linkages)• Nausea, vomiting, kidney toxicity, less myelosuppression Nausea, vomiting, kidney toxicity, less myelosuppression

than with alkylating agentsthan with alkylating agents



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• AntimetabolitesAntimetabolites• Purine/pyrimidine analogsPurine/pyrimidine analogs

• 5-FU, cytosine arabinoside, gemcitabine, 5-FU, cytosine arabinoside, gemcitabine, iododeoxyuridineiododeoxyuridine

• AntifolatesAntifolates• MethotrexateMethotrexate

• interfere with normal cell function (e.g. DNA synthesis)interfere with normal cell function (e.g. DNA synthesis) • Cell cycle specific, tend to cause DNA damage and block Cell cycle specific, tend to cause DNA damage and block

repair, less carcinogenic than alkylating agentsrepair, less carcinogenic than alkylating agents



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• Topoisomerase inhibitorsTopoisomerase inhibitors• Topo I inhibitorsTopo I inhibitors

• Camptothecin derivatives such as topotecan, irinotecan (CPT11)Camptothecin derivatives such as topotecan, irinotecan (CPT11)• Topo II inhibitors Topo II inhibitors

• Epipodophyllotoxins such as etoposide, teniposideEpipodophyllotoxins such as etoposide, teniposide• Topo II inhibitors plus other effectsTopo II inhibitors plus other effects

• Anthracyclines such as daunorubicin, doxorubicin (Adriamycin), Anthracyclines such as daunorubicin, doxorubicin (Adriamycin), idarubicin, epirubicinidarubicin, epirubicin

• Topoisomerases relax dsDNA to allow Topoisomerases relax dsDNA to allow replication/transcription by single (I) or double (II) strand replication/transcription by single (I) or double (II) strand nick. DSBs form when the replication fork meets the nick. DSBs form when the replication fork meets the DNA/topo cleavable complex - in S phaseDNA/topo cleavable complex - in S phase



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• Antimicrotubular agentsAntimicrotubular agents• Vinca alkaloidsVinca alkaloids• Taxanes: paclitaxel (Taxol), docetaxel (Taxotere)Taxanes: paclitaxel (Taxol), docetaxel (Taxotere)• Bind to tubulins (different site) and inhibit microtubular Bind to tubulins (different site) and inhibit microtubular

disassemblydisassembly• Cause G2M arrestCause G2M arrest



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OthersOthers

• Proteasome InhibitorsProteasome Inhibitors • Bortezumib, Velcade, PS-341Bortezumib, Velcade, PS-341• Boronic acid dipeptideBoronic acid dipeptide• Inhibits proteasome core chymotryptic activity reversiblyInhibits proteasome core chymotryptic activity reversibly• Effective in drug refractory multiple myelomaEffective in drug refractory multiple myeloma• CausesCauses

– Cell cycle arrestCell cycle arrest– Apoptosis of cancer cellsApoptosis of cancer cells– ImmunosuppressionImmunosuppression– Anti-inflammatoryAnti-inflammatory– Anti-angiogenesisAnti-angiogenesis– Downregulation of NF-Downregulation of NF-B (and many other signal transduction B (and many other signal transduction

molecules)molecules)• Radiosensitizer and chemosensitizerRadiosensitizer and chemosensitizer


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Chemotherapeutic ConsiderationsChemotherapeutic Considerations

• PharmacokineticsPharmacokinetics• Concentration of metabolites over timeConcentration of metabolites over time

• Absorption, Distribution, Metabolism, Absorption, Distribution, Metabolism, EliminationElimination

• PharmacodynamicsPharmacodynamics• Cellular response to drugCellular response to drug


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• PharmacokineticsPharmacokinetics• Concentration of metabolites over timeConcentration of metabolites over time

• Normally measured by the area under the Normally measured by the area under the concentration/time curveconcentration/time curve

• However, maintaining a certain level may be However, maintaining a certain level may be more important for some drugs than othersmore important for some drugs than others

• Continuous delivery better than bolus Continuous delivery better than bolus • Topo I inhibitors, anti-metabolites, Topo I inhibitors, anti-metabolites,

taxanestaxanes


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• PharmacokineticsPharmacokinetics• Absorption, Distribution, Metabolism, EliminationAbsorption, Distribution, Metabolism, Elimination

• AbsorptionAbsorption• Depends on route of administrationDepends on route of administration

• Intravenous route preferred for pharmacokinetic reasonsIntravenous route preferred for pharmacokinetic reasons• Oral is best for some eg TemozolomideOral is best for some eg Temozolomide• Regional delivery may be more effective (glioma)Regional delivery may be more effective (glioma)• Influenced by physical form and barriers to Influenced by physical form and barriers to

penetration/absorption e.g. blood-brain barrierpenetration/absorption e.g. blood-brain barrier• DistributionDistribution

• Requires blood/fluid flow to organs/tissues/tumorRequires blood/fluid flow to organs/tissues/tumor• Diffusion kineticsDiffusion kinetics

• Size and chemical formSize and chemical form• Protein and tissue binding, lipid solubility, pH, etc.Protein and tissue binding, lipid solubility, pH, etc.


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•PharmacokineticsPharmacokinetics• MetabolismMetabolism

• Phase 1 active metabolites often produced in liverPhase 1 active metabolites often produced in liver• Phase II inactive metabolites produced by conjugationPhase II inactive metabolites produced by conjugation• Some drugs requires activation (cyclophosphamide)Some drugs requires activation (cyclophosphamide)• Influenced by genetic polymorphisms (5-FU - Influenced by genetic polymorphisms (5-FU -

dihydropyrimidine dehydrogenase deficiency is toxic dihydropyrimidine dehydrogenase deficiency is toxic and high thymidylate synthase levels decrease efficacy)and high thymidylate synthase levels decrease efficacy)

• Liver function affects metabolism Liver function affects metabolism • ExcretionExcretion

• Primarily in kidney or biliary tractPrimarily in kidney or biliary tract• Phase I active metabolites (carboplatin) or Phase II Phase I active metabolites (carboplatin) or Phase II

metabolites (doxorubicin) can give toxicitymetabolites (doxorubicin) can give toxicity• Kidney function affects clearanceKidney function affects clearance• Influenced by protein and tissue binding, lipid solubility, Influenced by protein and tissue binding, lipid solubility,

pH, etc.pH, etc.• Doxorubicin slow release is due to high lipid solubilityDoxorubicin slow release is due to high lipid solubility


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• PharmacodynamicsPharmacodynamics• Cellular response to drug depends onCellular response to drug depends on

• MicroenvironmentMicroenvironment• Cell cycle phaseCell cycle phase• Drug resistance mechanismsDrug resistance mechanisms• Intracellular metabolismIntracellular metabolism• Sensitivity to cell death/survival pathwaysSensitivity to cell death/survival pathways

• Difficult to get predictors from in vitro Difficult to get predictors from in vitro survival datasurvival data


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MicroenvironmentMicroenvironment

0.001

0.01

0.1

1

10

0 50 100 150 200 250

Sur

vivi

ng f

ract

ion

µg/ml bleomycin

AeratedAerated

Bleomycin, Bleomycin, procarbazine,dactinomycinprocarbazine,dactinomycin

HypoxicHypoxic

less sensitiveless sensitive

10

µM mitomycin

Aerated

Mitomycin C, misonidazole, metronidazole, etanidazole, tirapazamine, doxorubicin

Hypoxic

more sensitivemore sensitive

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Cell CycleCell Cycle

G1/S phaseG1/S phaseAlkylating Agents, Alkylating Agents,

CisplatinCisplatin

M PhaseM PhaseAlkylatingAlkylating

AgentsAgentsG2 phaseG2 phasePaclitaxelPaclitaxelBleomycinBleomycin

S phaseS phaseDocetaxelDocetaxel

MethotrexateMethotrexateAra-C, 6TG,Ara-C, 6TG,HydroxyureaHydroxyureaVinblastineVinblastineDoxorubicinDoxorubicin

G0 - quiescenceG0 - quiescence


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MechanismMechanismDecreased uptakeDecreased uptakeIncreased effluxIncreased efflux

Decrease in drug activationDecrease in drug activationIncrease in drug catabolismIncrease in drug catabolismIncrease or decrease in levels of Increase or decrease in levels of

target moleculetarget moleculeAlterations in target moleculeAlterations in target molecule

Inactivation by binding to Inactivation by binding to sulfhydryls (e.g. glutathione)sulfhydryls (e.g. glutathione)

Increased DNA repairIncreased DNA repair

Decreased ability to undergo Decreased ability to undergo apoptosisapoptosis

DrugsDrugsMethotrexate, melphalan, cisplatinMethotrexate, melphalan, cisplatinAnthracyclines, vinca alkaloids, Anthracyclines, vinca alkaloids,

etoposide, taxanesetoposide, taxanesMany antimetabolitesMany antimetabolitesMany antimetabolitesMany antimetabolitesMethotrexate, topoisomerase inhibitorsMethotrexate, topoisomerase inhibitors

Methotrexate, other antimetabolites, Methotrexate, other antimetabolites, topoisomerase inhibitors, Gleevectopoisomerase inhibitors, Gleevec

Alkylating agents, cisplatin, Alkylating agents, cisplatin, anthracyclinesanthracyclines

Alkylating agents, cisplatin, Alkylating agents, cisplatin, anthracyclines, etoposideanthracyclines, etoposide

Alkylating agents, cisplatin, Alkylating agents, cisplatin, anthracyclines, etoposideanthracyclines, etoposide

Mechanisms of Drug ResistanceMechanisms of Drug Resistance


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Mechanisms of Drug ResistanceMechanisms of Drug Resistance

• Impaired drug influxImpaired drug influx• passive diffusion passive diffusion

• energy & temperature independentenergy & temperature independent• facilitated diffusion facilitated diffusion

• transport carrier on membrane transport carrier on membrane • energy & temperature independentenergy & temperature independent

• active transport active transport • carrier-mediated processcarrier-mediated process• energy & temperature dependentenergy & temperature dependent• reduced folate carrier - mutation?reduced folate carrier - mutation?• Melphalan Melphalan binding affinity for drug and binding affinity for drug and number of number of

transport sites / slower carrier mobilitytransport sites / slower carrier mobility


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Mechanisms of Drug ResistanceMechanisms of Drug Resistance• Increased drug effluxIncreased drug efflux• Many natural drugs/derivatives (taxanes, vinca alkaloids, Many natural drugs/derivatives (taxanes, vinca alkaloids,

anthracyclines) have shared mechanisms of resistance, anthracyclines) have shared mechanisms of resistance, e.g. substrates for membrane-based ATPase-dependent e.g. substrates for membrane-based ATPase-dependent proteins (pumps)proteins (pumps)

• P-glycoprotein (P-glycoprotein (mdr1mdr1))• High levels in kidney & adrenals; intermediate in lung, High levels in kidney & adrenals; intermediate in lung,

liver, colon and rectumliver, colon and rectum• Co-specificity with proteasome enzymesCo-specificity with proteasome enzymes• InhibitorsInhibitors

• Calcium channel blockers (verapamil)Calcium channel blockers (verapamil)• Cyclosporin ACyclosporin A• Tariquidar, zosuquidar (phase 1/2)Tariquidar, zosuquidar (phase 1/2)


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Summary of Drug TherapySummary of Drug Therapy

• Plethora of cytotoxic agentsPlethora of cytotoxic agents• Selective (not exclusive) targets - proliferating cellsSelective (not exclusive) targets - proliferating cells• Major problem: drug resistanceMajor problem: drug resistance

• Principal mechanismsPrincipal mechanisms• altered membrane transport (P-glycoprotein);altered membrane transport (P-glycoprotein);• altered target enzyme (mutated topoisomerase II)altered target enzyme (mutated topoisomerase II)• decreased drug activationdecreased drug activation• increased drug degradation (e.g. altered expression of drug-increased drug degradation (e.g. altered expression of drug-

metabolizing enzyme)metabolizing enzyme)• drug inactivation (conjugation with glutathione)drug inactivation (conjugation with glutathione)• drug interactionsdrug interactions• enhanced DNA repair; failure to apoptose (e.g. mutation of p53)enhanced DNA repair; failure to apoptose (e.g. mutation of p53)


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How Effective is CT - and how is How Effective is CT - and how is it best combined with RT?it best combined with RT?

• Responses are often referred to as PR or CR. Responses are often referred to as PR or CR. – Defined by the endpoint - pathology/imaging/clinicalDefined by the endpoint - pathology/imaging/clinical– If a tumor has 10If a tumor has 101010 cells, a PR may decrease this to cells, a PR may decrease this to

2x102x1099, which is not much of an improvement., which is not much of an improvement.• Patients in complete remission can have anywhere Patients in complete remission can have anywhere

between 0-10between 0-1099 cells as a tumor burden. If 10yr relapse- cells as a tumor burden. If 10yr relapse-free survival is 30% without and 40-45% with adjuvant free survival is 30% without and 40-45% with adjuvant chemotherapy, as is the case in early breast cancer chemotherapy, as is the case in early breast cancer regimens, Withers calculated that this represents about regimens, Withers calculated that this represents about 2 logs of tumor cell kill – easy to achieve with RT.2 logs of tumor cell kill – easy to achieve with RT.

• Neoadjuvant chemotherapy may cause accelerated Neoadjuvant chemotherapy may cause accelerated tumor repopulation! Concomitant delivery of drugs with tumor repopulation! Concomitant delivery of drugs with RT is often better than sequential delivery. RT is often better than sequential delivery.


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Therapeutic IndexTherapeutic Index

• Need to increase therapeutic indexNeed to increase therapeutic index • Bone marrow major toxicityBone marrow major toxicity• Normally treat to MTD, except for palliative Normally treat to MTD, except for palliative

cases (5-FU for advanced colorectal Ca)cases (5-FU for advanced colorectal Ca)• Some tumors are drug Some tumors are drug ““resistantresistant”” others are others are

““sensitivesensitive”” but recur - are the cancer stem but recur - are the cancer stem cells being killed? Many seem to have cells being killed? Many seem to have enhanced drug efflux pumps…..enhanced drug efflux pumps…..


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Combination TherapiesCombination Therapies• CT combinationsCT combinations

− Different classes of agents with minimally Different classes of agents with minimally overlapping toxicitiesoverlapping toxicities

• RT plus CTRT plus CT• Adjuvant therapy (P-glycoprotein inhibitors)Adjuvant therapy (P-glycoprotein inhibitors)• Biological targeting + CT/RTBiological targeting + CT/RT


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Chemotherapy and RadiationChemotherapy and Radiation• Combination of chemotherapy and radiation can Combination of chemotherapy and radiation can

increase cure rate, but also the potential for normal increase cure rate, but also the potential for normal tissue toxicitytissue toxicity

• Dose Enhancement Ratio (DER)Dose Enhancement Ratio (DER)• Dose of radiation alone to produce an effect divided by Dose of radiation alone to produce an effect divided by

dose of radiation to give same effect in combination with dose of radiation to give same effect in combination with drugdrug

• Therapeutic Gain FactorTherapeutic Gain Factor• Ratio of DER for tumor to DER of dose-limiting normal Ratio of DER for tumor to DER of dose-limiting normal

tissuetissue


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Synergy vs. AdditivitySynergy vs. Additivity

Claims for synergy are often made if SClaims for synergy are often made if S11 = S = SAA x S x SBB

but this is only true if there is no shoulder.but this is only true if there is no shoulder.Tannock et al: The Basic Science of Oncology 4th Ed.Tannock et al: The Basic Science of Oncology 4th Ed.

SS11

0 1 2 3 4 5 6

Drug A + BDrug A + B

10-3

10-2

10-1

1

X??DDAA

0 1 2 3 4 5 6

DDAA

SSAA

1010-3-3

1010-2-2

1010-1-1

11 Drug ADrug A

1010-3-3

1010-2-2

1010-1-1

11 Drug BDrug B

DDBBSSBB

0 1 2 3 4 5 6

DDBB


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Dose of Agent B

Dose of Agent A

Supra-additiveSynergistic

Envelope of Additivity

SubadditiveProtectiveAntagonistic

After Steel and Peckham, 1959

Isobologram AnalysisIsobologram Analysis


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CisplatinCisplatin

• Most commonly used drug with RTMost commonly used drug with RT• Forms DNA-DNA and DNA-protein inter- and intra-Forms DNA-DNA and DNA-protein inter- and intra-

strand crosslinks, inhibiting DNA replication and RNA strand crosslinks, inhibiting DNA replication and RNA transcriptiontranscription

• DNA distortion leads to binding of MSH and HMG DNA distortion leads to binding of MSH and HMG and other proteinsand other proteins

• ATM and ATR, CHK1 and 2 activated for cell cycle ATM and ATR, CHK1 and 2 activated for cell cycle arrestarrest

• With RT, fixation of DNA damage, less repair, more With RT, fixation of DNA damage, less repair, more apoptosisapoptosis


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5-FU5-FU• Thymidine phosphorylase –converts 5-FU to FdUrd, Thymidine phosphorylase –converts 5-FU to FdUrd,

which thymidine kinase converts into FdUMP, which which thymidine kinase converts into FdUMP, which inhibits thymidine synthase and DNA synthesis and inhibits thymidine synthase and DNA synthesis and repair.repair.– May be major mechanism for continuous infusionMay be major mechanism for continuous infusion

• At the RNA level, uridine phosphorylase transforms At the RNA level, uridine phosphorylase transforms 5-FU into FdUrd, which uridine kinase converts into 5-FU into FdUrd, which uridine kinase converts into 5-FU monophosphate that becomes di- and tri-5-FU monophosphate that becomes di- and tri-phosphate, which is a substrate for RNA polymerase, phosphate, which is a substrate for RNA polymerase, leading to decreased mRNA stability.leading to decreased mRNA stability.– May work best with bolus infusion May work best with bolus infusion


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GemcitabineGemcitabine

• Pyrimidine analogPyrimidine analog– Depletion of deoxynucleoside triphosphate Depletion of deoxynucleoside triphosphate

pool. Incorporation into DNA inhibits DNA pool. Incorporation into DNA inhibits DNA synthesis and repairsynthesis and repair

– HR importantHR important– Does not work with loss of MLH1Does not work with loss of MLH1


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ChemoRTChemoRT

123 patients123 patients64 Gy RT64 Gy RTversusversus50 Gy RT 50 Gy RT with 4 cycleswith 4 cyclesof 5-FU - CDDPof 5-FU - CDDP

Al-Sarraf et al, JCO, 1997


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ChemoRTChemoRT• Meta-analyses have shown that chemotherapy Meta-analyses have shown that chemotherapy

(concomitant, neoadjuvant, adjuvant) improves (concomitant, neoadjuvant, adjuvant) improves survival in non-metastatic HNSCC (other than NPC) survival in non-metastatic HNSCC (other than NPC) by 4.4% at 5yrs. by 4.4% at 5yrs. – Bourhis et al PASCO 22:488, 2004Bourhis et al PASCO 22:488, 2004

• Concomitant gives an absolute benefit of 6.5-8% at Concomitant gives an absolute benefit of 6.5-8% at 5yrs, irrespective of fractionation scheme although 5yrs, irrespective of fractionation scheme although altered fractionation gives a survival advantage, and is altered fractionation gives a survival advantage, and is better than neoadjuvant. Platinum-based regimens better than neoadjuvant. Platinum-based regimens best. It comes with an increase in early and late best. It comes with an increase in early and late toxicity.toxicity.– Pignon et al IJROBP 69: S112, 2007 Pignon et al IJROBP 69: S112, 2007


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• Chemoradiation in the management of esophageal cancer.Chemoradiation in the management of esophageal cancer.• Kleinberg L, , Forastiere AA. . J Clin Oncol. 2007 Sep 10;25(26):4110-7 2007 Sep 10;25(26):4110-7• The combination of chemotherapy, fluorouracil and cisplatin, and radiation has The combination of chemotherapy, fluorouracil and cisplatin, and radiation has

improved outcome for patients with esophageal cancer. A randomized improved outcome for patients with esophageal cancer. A randomized controlled trial confirmed a long-term survival benefit when this chemotherapy controlled trial confirmed a long-term survival benefit when this chemotherapy was added to radiotherapy for squamous cell carcinoma, but the approach has was added to radiotherapy for squamous cell carcinoma, but the approach has not been definitively assessed in patients with adenocarcinoma. Preoperative not been definitively assessed in patients with adenocarcinoma. Preoperative chemoradiotherapy has been tested in numerous phase II studies and chemoradiotherapy has been tested in numerous phase II studies and underpowered or flawed phase III studies. Nevertheless, collectively, the underpowered or flawed phase III studies. Nevertheless, collectively, the evidence strongly suggests that preoperative chemoradiotherapy improves evidence strongly suggests that preoperative chemoradiotherapy improves outcome, and thus, this strategy has become a standard treatment option. outcome, and thus, this strategy has become a standard treatment option. Attempts to improve outcome by intensifying conventional cytotoxic drugs or Attempts to improve outcome by intensifying conventional cytotoxic drugs or increasing the radiation dose have not been successful. Camptothecin and increasing the radiation dose have not been successful. Camptothecin and taxane-based regimens combined with radiation have altered the toxicity profile, taxane-based regimens combined with radiation have altered the toxicity profile, but substantial improvement in survival outcomes has yet to be demonstrated. but substantial improvement in survival outcomes has yet to be demonstrated. Future improvements will likely require the incorporation of targeted agents that Future improvements will likely require the incorporation of targeted agents that add minimally to existing toxicity, the use of molecular predictors of response to add minimally to existing toxicity, the use of molecular predictors of response to individualize selection of the chemotherapeutic regimen, and early identification individualize selection of the chemotherapeutic regimen, and early identification of responders such that therapy might be altered dynamically.of responders such that therapy might be altered dynamically.


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• Randomized Phase III Trial of Sequential Randomized Phase III Trial of Sequential Chemoradiotherapy Compared With Concurrent Chemoradiotherapy Compared With Concurrent Chemoradiotherapy in Locally Advanced Nonsmall-Cell Chemoradiotherapy in Locally Advanced Nonsmall-Cell Lung Cancer Lung Cancer

• Fournel et al Fournel et al Journal of Clinical OncologyJournal of Clinical Oncology, 23; 5910-5917, 2005., 23; 5910-5917, 2005.• Two hundred five patients were randomly assigned. PretreatmentTwo hundred five patients were randomly assigned. Pretreatment characteristics characteristics

were well balanced between the two arms. Therewere well balanced between the two arms. There were six toxic deaths in the were six toxic deaths in the sequential arm and 10 in the concurrentsequential arm and 10 in the concurrent arm. Median survival was 14.5 months arm. Median survival was 14.5 months in the sequential arm andin the sequential arm and 16.3 months in the concurrent arm (log-rank test 16.3 months in the concurrent arm (log-rank test PP = .24). = .24). Two-,Two-, 3-, and 4-year survival rates were better in the concurrent3-, and 4-year survival rates were better in the concurrent arm arm (39%, 25%, and 21%, respectively) than in the sequential(39%, 25%, and 21%, respectively) than in the sequential arm (26%, 19%, and arm (26%, 19%, and 14%, respectively). 14%, respectively). Esophageal toxicity wasEsophageal toxicity was significantly more frequent in the significantly more frequent in the concurrent arm than in theconcurrent arm than in the sequential arm (32% sequential arm (32% vv 3%) 3%). CONCLUSION: . CONCLUSION: Although not statistically significant, clinically importantAlthough not statistically significant, clinically important differences in the differences in the median, 2-, 3-, and 4-year survival ratesmedian, 2-, 3-, and 4-year survival rates were observed, with a trend in favor of were observed, with a trend in favor of concurrent chemoradiationconcurrent chemoradiation therapy, therapy, suggesting that is the optimal strategy for suggesting that is the optimal strategy for patientspatients with locally advanced NSCLCwith locally advanced NSCLC..


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Evaluation of early and late toxicities in chemoradiation trials.Evaluation of early and late toxicities in chemoradiation trials.Bentzen SM, , Trotti AJ Clin Oncol. 2007 Sep 10;25(26):4096-103 2007 Sep 10;25(26):4096-103Combined chemoradiotherapy is increasingly becoming a standard of care for the Combined chemoradiotherapy is increasingly becoming a standard of care for the nonoperative management of a variety of solid malignancies. A string of randomized nonoperative management of a variety of solid malignancies. A string of randomized controlled phase III trials have shown statistically significant and clinically relevant controlled phase III trials have shown statistically significant and clinically relevant improvements in outcome, ostensibly without any apparent increase in late toxicity. improvements in outcome, ostensibly without any apparent increase in late toxicity. However, However, the reliability and the sensitivity of toxicity reporting in most trials are the reliability and the sensitivity of toxicity reporting in most trials are questionable. Audits and phase IV studies suggest that the chemoradiotherapy questionable. Audits and phase IV studies suggest that the chemoradiotherapy success comes at a price in terms of late toxicity. success comes at a price in terms of late toxicity. This review presents some of the This review presents some of the challenges in recording, analyzing, and reporting toxicity data. METHODS for challenges in recording, analyzing, and reporting toxicity data. METHODS for summarizing toxicity are reviewed, and a new investigational metric, the TAME summarizing toxicity are reviewed, and a new investigational metric, the TAME reporting system, is discussed. The need for special vigilance in the era of reporting system, is discussed. The need for special vigilance in the era of molecular-targeted agents is emphasized because of the possibility that unexpected molecular-targeted agents is emphasized because of the possibility that unexpected serious adverse events with a low incidence may occur. Finally, we discuss how serious adverse events with a low incidence may occur. Finally, we discuss how progress in molecular pathology and radiation biology may provide novel progress in molecular pathology and radiation biology may provide novel opportunities for stratifying patients according to risk of adverse effects, opportunities for stratifying patients according to risk of adverse effects, interventional targets for reducing or treating adverse effects, and surrogate markers interventional targets for reducing or treating adverse effects, and surrogate markers of normal-tissue injury.of normal-tissue injury.


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• Phase III Study of Concurrent Chemoradiotherapy Versus Phase III Study of Concurrent Chemoradiotherapy Versus Radiotherapy Alone for Advanced Nasopharyngeal Carcinoma: Radiotherapy Alone for Advanced Nasopharyngeal Carcinoma: Positive Effect on Overall and Progression-Free SurvivalPositive Effect on Overall and Progression-Free Survival

• Lin et al.Lin et al. Journal of Clinical Oncology Journal of Clinical Oncology 21: 631-637, 2003 21: 631-637, 2003• Two cycles of concurrent chemotherapyTwo cycles of concurrent chemotherapy with cisplatin 20 mg/mwith cisplatin 20 mg/m22/dy plus /dy plus

fluorouracil 400 mg/mfluorouracil 400 mg/m22/d by 96-hour/d by 96-hour continuous infusion during the weeks continuous infusion during the weeks 1 and 5 of RT. Median follow-up of 65 months, 26.2% (371 and 5 of RT. Median follow-up of 65 months, 26.2% (37 of 141) and of 141) and 46.2% (66 of 143) of patients developed tumor relapse46.2% (66 of 143) of patients developed tumor relapse in the CCRT and in the CCRT and RT-alone groups, respectively. The 5-year overallRT-alone groups, respectively. The 5-year overall survival rates were survival rates were 72.3% for the CCRT arm and 54.2% for the72.3% for the CCRT arm and 54.2% for the RT-only arm (RT-only arm (PP = .0022). The = .0022). The 5-year progression-free survival5-year progression-free survival rates were 71.6% for the CCRT group rates were 71.6% for the CCRT group compared with 53.0% forcompared with 53.0% for the RT-only group (the RT-only group (PP = .0012). Although = .0012). Although significantly more toxicitysignificantly more toxicity was noted in the CCRT arm, including was noted in the CCRT arm, including leukopenia and emesisleukopenia and emesis,, compliance with the combined treatment was compliance with the combined treatment was good. The secondgood. The second cycle of concurrent chemotherapy was refused by nine cycle of concurrent chemotherapy was refused by nine patientspatients and was delayed for 1 week for another nine patients. and was delayed for 1 week for another nine patients.


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• ASTRO 2007: Temozolomide (Temodar) Offers Long-Term Survival for Glioblastoma

• Mirimanoff

• 10.9% at two years for patients getting radiation alone, compared with 27.2% for those getting radiation and the medication. At three years, the corresponding rates were 4.4% and 16.4%. At four years, the rates were 3% and 12.1%.The differences were significant at P<0.0001.

• Patients (48% of total) with a methylated methylguanine methyl transferase (MGMT) promoter, …. had a four-year survival of 22.1% if they had the combination therapy, compared to 5.2% for radiation alone. The difference was significant at P=0.04.


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• Hedgehog signal activation in oesophageal cancer patients undergoing neoadjuvant Hedgehog signal activation in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy.chemoradiotherapy.

• Br J Cancer. 2008 May 20;98(10):1670-4. Epub 2008 May 13. 2008 May 20;98(10):1670-4. Epub 2008 May 13. • Yoshikawa R, , Nakano Y, , Tao LTao L, , Koishi KKoishi K, , Matsumoto TMatsumoto T, , Sasako MSasako M, , Tsujimura TTsujimura T, , Hashimoto-Hashimoto-

Tamaoki TTamaoki T, , Fujiwara YFujiwara Y..• The zinc finger protein glioma-associated oncogene homologue 1 (Gli-1) is a critical component of The zinc finger protein glioma-associated oncogene homologue 1 (Gli-1) is a critical component of

the Hedgehog (Hh) signalling pathway, which is essential for morphogenesis and stem-cell renewal, the Hedgehog (Hh) signalling pathway, which is essential for morphogenesis and stem-cell renewal, and is dysregulated in many cancer types. As data were not available on the role of Gli-1 and is dysregulated in many cancer types. As data were not available on the role of Gli-1 expression in oesophageal cancer progression, we analysed whether it could be used to predict expression in oesophageal cancer progression, we analysed whether it could be used to predict disease progression and prognosis in oesophageal cancer patients undergoing neoadjuvant disease progression and prognosis in oesophageal cancer patients undergoing neoadjuvant chemoradiotherapy (CRT). Among 69 patients with histologically confirmed oesophageal squamous chemoradiotherapy (CRT). Among 69 patients with histologically confirmed oesophageal squamous cell carcinomas (ESCCs), 25 showed a pathological complete response after preoperative CRT. cell carcinomas (ESCCs), 25 showed a pathological complete response after preoperative CRT. Overall survival (OS) was significantly associated with lymph-node metastasis, distant metastasis, Overall survival (OS) was significantly associated with lymph-node metastasis, distant metastasis, and CRT, and was further correlated with the absence of both Gli-1 nuclear expression and residual and CRT, and was further correlated with the absence of both Gli-1 nuclear expression and residual tumour. All patients with Gli-1 nuclear expression (10.1%) had distant or lymph-node metastasis, tumour. All patients with Gli-1 nuclear expression (10.1%) had distant or lymph-node metastasis, and six out of seven died within 13 months. Furthermore, patients with Gli-1 nuclear-positive and six out of seven died within 13 months. Furthermore, patients with Gli-1 nuclear-positive cancers showed significantly poorer prognoses than those without (disease-free survival: mean cancers showed significantly poorer prognoses than those without (disease-free survival: mean DFS time 250 vs 1738 months, 2-year DFS 0 vs 54.9%, P=0.009; OS: mean OS time 386 vs 1742 DFS time 250 vs 1738 months, 2-year DFS 0 vs 54.9%, P=0.009; OS: mean OS time 386 vs 1742 months, 2-year OS 16.7 vs 54.9%, P=0.001). months, 2-year OS 16.7 vs 54.9%, P=0.001). Our study provides the first evidence that Gli-1 Our study provides the first evidence that Gli-1 nuclear expression is a strong and independent predictor of early relapse and poor prognosis in nuclear expression is a strong and independent predictor of early relapse and poor prognosis in ESCC after CRT. These findings suggest that Hh signal activation might promote cancer regrowth ESCC after CRT. These findings suggest that Hh signal activation might promote cancer regrowth and progression after CRT.and progression after CRT.


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Exploiting Low Tumor Exploiting Low Tumor Oxygenation with Hypoxic Oxygenation with Hypoxic

CytotoxinsCytotoxins


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Capillary

150

O2 O2 O2

Hypoxia Causes Resistance to Radiation Hypoxia Causes Resistance to Radiation

and Anticancer Drugsand Anticancer Drugs

100500

Distance from Capillary (µm)

.

Su

rviv

ing

Fra

ctio

n

Radiation / Chem. Drug

Combined

Hypoxic Cytotoxin

Hypoxic cytotoxins should have an at least additive effect with RT


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Radiosensitization by Targeting HypoxiaRadiosensitization by Targeting Hypoxia• Anemia has a -ve effect on RT outcomeAnemia has a -ve effect on RT outcome

• Blood transfusionsBlood transfusions• EPO potentiates tumor growth!!!!EPO potentiates tumor growth!!!!

• Hyperbaric oxygenHyperbaric oxygen• Pure oxygen at 3 atmospheresPure oxygen at 3 atmospheres• Small patient numbers, unconventional fxSmall patient numbers, unconventional fx

• Perfluorocarbon emulsionsPerfluorocarbon emulsions• oxygen carrying capacity of bloodoxygen carrying capacity of blood

• Efaproxiral: synthetic modifier of hemaglobinEfaproxiral: synthetic modifier of hemaglobin• ARCONARCON

• AR = accelerated radiation for proliferation; CO = AR = accelerated radiation for proliferation; CO = carbogen (95% Ocarbogen (95% O22; 5% CO; 5% CO22) for chronic hypoxia; N ) for chronic hypoxia; N

= nicotinamide (vitamin B3 analogue) for acute = nicotinamide (vitamin B3 analogue) for acute hypoxiahypoxia


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Randomized HBO StudiesRandomized HBO Studies

Medical Research Council


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Hypoxic CytotoxinsHypoxic Cytotoxins• QuinonesQuinones

– Mitomycin CMitomycin C• Differential between hypoxic and oxic cells poorDifferential between hypoxic and oxic cells poor• Requires very low levels of oxygen for maximum cytotoxicityRequires very low levels of oxygen for maximum cytotoxicity

• NitroaromaticsNitroaromatics• Benzotriazine di-N-oxidesBenzotriazine di-N-oxides

– TirapazamineTirapazamine• Good differential between oxic and hypoxic cellsGood differential between oxic and hypoxic cells• Phase III clinical trials with cisplatinPhase III clinical trials with cisplatin• Phase II with RTPhase II with RT


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Mechanism of Hypoxic Cytotoxicity Mechanism of Hypoxic Cytotoxicity of Tirapazamineof Tirapazamine

2

O

NN

N NH

O

1 e + H- +

NN

N NH

O

OH

2Reductase

TPZ

Hypoxia

*

*

*

TPZ Radical

.

2

-

OO2

M. BrownM. Brown


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Tirapazamine is Toxic Tirapazamine is Toxic for Hypoxic Cells for Hypoxic Cells in vitroin vitro

10000100010010110-5

10-4

10-3

10-2

10-1

100

Tirapazamine Conc (M)

Sur

vivi

ng

Fra

ctio

nHCR= 300

hypoxiahypoxiaairair


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Lung Cancer

CervixCancer

Head & Neck Cancer

Tirapazamine has shown Clinical Efficacy Tirapazamine has shown Clinical Efficacy when Combined with XRT or when Combined with XRT or

ChemotherapyChemotherapy

Currently off the market! ....toxicity issues.


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• Halogenated pyrimidinesHalogenated pyrimidines• 5-iododeoxyuridine (IudR), 5-bromo-deoxyuridine (BrdU)5-iododeoxyuridine (IudR), 5-bromo-deoxyuridine (BrdU)• Activity is dependent on amount of incorporation into Activity is dependent on amount of incorporation into

DNADNA• Blocks DNA repair and sensitize to RTBlocks DNA repair and sensitize to RT• Limited clinical usefulness due to toxicityLimited clinical usefulness due to toxicity

Radiation SensitizersRadiation Sensitizers


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RadiosensitizersRadiosensitizers

From Zeman, 2000


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RadiosensitizersRadiosensitizers

• Radiosensitizers such as nitroimidazoles can Radiosensitizers such as nitroimidazoles can ““mimicmimic”” oxygen and fix damage oxygen and fix damage– Associated with some toxicity and there were only rarely efforts Associated with some toxicity and there were only rarely efforts

to determine if the tumors were hypoxic in advance of treatmentto determine if the tumors were hypoxic in advance of treatment

– However there have been positive trials……However there have been positive trials……

• DAHANCA 5 trial using nimorazole in treatment of advanced squamous cell carcinoma of the head and neck


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• NitroimidazolesNitroimidazoles

misonidazolemisonidazole

CHCH22CH(OH)CHCH(OH)CH22OCHOCH33

NN

NN

NONO22

etanidazoleetanidazole

CHCH22CONH CHCONH CH22 CH CH22OHOH

NN

NN

NONO22

metronidazolemetronidazole

CHCH22CHCH22OHOH

NN

NN

CHCH33OO22NN

OO

nimorazolenimorazole

CHCH22CHCH22NN

NN

NN

OO22NN


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Misonidazole: Misonidazole: good sensitization in vitro and in vivo preclinical modelsgood sensitization in vitro and in vivo preclinical models

O Air Air + Misonidazole (1 mmol dm-3) Air + Misonidazole (10 mmol dm-3) Nitrogen Nitrogen + Misonidazole (1 mmol dm-3) Nitrogen + Misonidazole (10 mmol dm-3)

X-rays X-rays ++

1 mg/g 1 mg/g misomiso

TCDTCD5050 = 43.8 Gy = 43.8 Gy24.1 Gy24.1 Gy

Sensitizer Sensitizer enhancement ratio enhancement ratio

= 1.8 ± 0.1= 1.8 ± 0.1

100100

00

% t

umo

rs c

ontr

olle

d%

tum

ors

con

trol

led

DoseDose2020 3030 4040 5050 6060

X-rays onlyX-rays only


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AgentAgent Number of Number of TrialsTrials

Significant Significant benefitbenefit

Non-Non-significant significant

benefitbenefit

No benefitNo benefit

MisonidazoleMisonidazole 3939 44 44 3131

Clinical TrialsClinical Trials

Clinic:Clinic: dose-limiting toxicity -- peripheral dose-limiting toxicity -- peripheral neuropathy (reduced tolerated dose)neuropathy (reduced tolerated dose)


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And a meta-analysis by Jens Overgaard has shown significantly improved survival and loco-regional control

Journal of Clinical Oncology, 25: pp. 4066-4074, 2007


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Radiation SensitizersRadiation Sensitizers

• Hypoxia meta-analysis (Overgaard)Hypoxia meta-analysis (Overgaard)• 10,602 patients, 82 trials, HBO vs sensitizers vs 10,602 patients, 82 trials, HBO vs sensitizers vs

carbogen vs blood transfusionscarbogen vs blood transfusions• Greatest benefit in head & neck (largest group?)Greatest benefit in head & neck (largest group?)• Hypoxia problem Hypoxia problem in squamous cell carcinomas, in squamous cell carcinomas, in in

adenocarcinomasadenocarcinomas• Improvement in local control = 5%; Improvement in local control = 5%; survival = 3%; survival = 3%;

complication rate = 0.6% (NS)complication rate = 0.6% (NS)

Selection for patients with hypoxic tumors would help!!!!


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• Produce vasoconstriction or alter metabolism Produce vasoconstriction or alter metabolism causing reduction in oxygen concentration in causing reduction in oxygen concentration in tissue/organtissue/organ • sodium cyanide, carbon monoxide, epinephrine, sodium cyanide, carbon monoxide, epinephrine,

histamine, serotoninhistamine, serotonin• Scavenge free radicalsScavenge free radicals

• sulfhydryl compoundssulfhydryl compounds• dimethyl sulfoxide (DMSO), superoxide dismutase dimethyl sulfoxide (DMSO), superoxide dismutase

enzymes (SODs)enzymes (SODs)• Hydrogen atom donation to facilitate direct Hydrogen atom donation to facilitate direct

repair to a radical site on DNArepair to a radical site on DNA• glutathione, cysteine, WR compoundsglutathione, cysteine, WR compounds

Radiation ProtectorsRadiation Protectors


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WR compoundsWR compounds• WR-638 (cystaphos)WR-638 (cystaphos)

• Oral tablets carried by Soviet troopsOral tablets carried by Soviet troops• Requires intravenous or intraperitoneal administrationRequires intravenous or intraperitoneal administration

• WR-1607WR-1607• Effective radioprotector: dose of 10 mg/kgEffective radioprotector: dose of 10 mg/kg• CardiotoxicityCardiotoxicity• Marketed as d-CON (rat poison)Marketed as d-CON (rat poison)

• WR-2721 (amifostine)WR-2721 (amifostine)• Phosphorothioate -- prodrugPhosphorothioate -- prodrug• Dephosphorylation (alkaline phosphatase) Dephosphorylation (alkaline phosphatase) WR-1065WR-1065• Differential protection in normal tissues (bone marrow, gut, salivary Differential protection in normal tissues (bone marrow, gut, salivary

glands > lungs > brain)glands > lungs > brain)• For complete benefit, need to increase radiation dose?For complete benefit, need to increase radiation dose?• Clinical trials: some benefit -- RTOG phase III for xerostomiaClinical trials: some benefit -- RTOG phase III for xerostomia• Toxicity still an issue, as is fear of protecting tumorToxicity still an issue, as is fear of protecting tumor

NHNH22CHCH22CHCH22SPOSPO33HNaHNa

Radiation ProtectorsRadiation Protectors

CHCH33(CH(CH22))99NHCHNHCH22SSOSSO33HH


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RadioprotectorsRadioprotectors

• Thiols can protect either by Thiols can protect either by – scavenging free radicals scavenging free radicals

RSH + RSH + ..OH RS OH RS .. H2O H2O– hydrogen atom donation to radicals in hydrogen atom donation to radicals in

target molecules (chemical repair)target molecules (chemical repair)X X .. + RSH XH + RS + RSH XH + RS ..

RSRS.. Is recycled by the glutathione redox cycle Is recycled by the glutathione redox cycle


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RadioprotectorsRadioprotectors

CHO cells

control

DTT 25mmol

WR-151326

Cysteamine10mmol

Radioprotectors such as WR-2721Radioprotectors such as WR-2721(Ethyol:Amifostine), which contain (Ethyol:Amifostine), which contain thiol/sulfhydryl/SH groups workthiol/sulfhydryl/SH groups workin experimental systems, butin experimental systems, butclinically are associated with clinically are associated with side-effects if given systemically. side-effects if given systemically. May be useful if given locally or to May be useful if given locally or to prevent second cancers, which prevent second cancers, which seems to need a lower dose than for seems to need a lower dose than for radioprotectionradioprotection


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Questions:Questions: Interaction of Radiotherapy with other AgentsInteraction of Radiotherapy with other Agents


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Temozolomide (Temodar) is anTemozolomide (Temodar) is an

1.1. Alkylating agentAlkylating agent

2.2. Platinating agentPlatinating agent

3.3. AntimetaboliteAntimetabolite

4.4. Topoisomerase inhibitorTopoisomerase inhibitor

5.5. Anti-microtubular agentAnti-microtubular agent


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5-Fu is an5-Fu is an

1.1. Alkylating agentAlkylating agent

2.2. Platinating agentPlatinating agent

3.3. AntimetaboliteAntimetabolite

4.4. Topoisomerase inhibitorTopoisomerase inhibitor

5.5. Anti-microtubular agent Anti-microtubular agent


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Which of the following has its action Which of the following has its action adversely affected by hypoxiaadversely affected by hypoxia

1.1. Bleomycin Bleomycin

2.2. ProcarbazineProcarbazine

3.3. DactinomycinDactinomycin

4.4. DoxorubicinDoxorubicin


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Which of the following is true for the multiple Which of the following is true for the multiple drug resistance protein mdr1drug resistance protein mdr1

1.1. It blocks drug influx into tumor cellsIt blocks drug influx into tumor cells

2.2. It is expressed only in tumor cellsIt is expressed only in tumor cells

3.3. It increases drug eflux from a cell It increases drug eflux from a cell

4.4. It increases drug half-lifeIt increases drug half-life


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The dose enhancement ratio isThe dose enhancement ratio is

1.1. The dose of drug that is needed to enhance the effect of The dose of drug that is needed to enhance the effect of RTRT

2.2. The dose of radiation that is needed with the drug to that The dose of radiation that is needed with the drug to that without the drug for a given isoeffectwithout the drug for a given isoeffect

3.3. The dose of radiation alone to the dose of radiation with The dose of radiation alone to the dose of radiation with drug that is needed for a given isoeffectdrug that is needed for a given isoeffect

4.4. The tumor control probability with drug plus radiation The tumor control probability with drug plus radiation divided by that for radiation alone divided by that for radiation alone


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The meta-analysis by Overgaard on the role The meta-analysis by Overgaard on the role of hypoxia in RT indicated thatof hypoxia in RT indicated that

1.1. Sensitizers made no difference to overall Sensitizers made no difference to overall outcomeoutcome

2.2. Hypoxia is more of a problem with Hypoxia is more of a problem with adenocarcinomas than SCCadenocarcinomas than SCC

3.3. An overall improvement of about 5% in An overall improvement of about 5% in local control in HNSCC for sensitizers in local control in HNSCC for sensitizers in combination with RTcombination with RT

4.4. Sensitizers in tumors in all sites were Sensitizers in tumors in all sites were equally affected equally affected


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Which of the following is true about AmifostineWhich of the following is true about Amifostine

1.1. It is FDA approved as a radioprotector for It is FDA approved as a radioprotector for all normal tissuesall normal tissues

2.2. It is given orally or topicallyIt is given orally or topically

3.3. It needs to be dephosphoylated to be activeIt needs to be dephosphoylated to be active

4.4. It has shown efficacy in Phase III clinical It has shown efficacy in Phase III clinical trials protecting against mucositis in trials protecting against mucositis in HNSCC HNSCC


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AnswersAnswers

1. NA

2. 1

3. 3

4. 4

5. 3

6. 3

7. 3

8. 3

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Alkylating agents Platinating agents Antimetabolites Topoisomerase inhibitors

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