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Gene Therapy - Problems and

Challenges

Alison M. Beaney

Regional Quality AssuranceSpecialist

North-East and Yorkshire

Helapet Aseptic Study Day 2008

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Gene Therapy Background to Gene Therapy

P

otentialB

enefits Perceived Hazards and Risks

Regulations

Implications for

Phar

macy Aseptic Units

Future?

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Gene Therapy Definition

The deliberate introduction of genetic material intohuman somatic cells for therapeutic, prophylacticor diagnostic purposes

Addition of EXTRA genes

Aim is to cure disease (or at least help the patient)

First introduction of gene-

modified cells into a patientwas in 1989

First gene therapy product approved formarket in 2004

Still very experimental and early in its development

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PTQA April 2008 4

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Gene Therapy Vectors Vectors deliver genes to cells

Therapeutic gene(Transgene)

TherapeuticproteinVector for efficient gene delivery

Transcription

Translation

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Gene Therapy Strategies1) Gene Replacement

Replace faulty genes with normal genes

Corrects inherited genetic errors Provides a missing function

Monogenic diseases e.g. cystic fibrosis,haemophilia, X-SCID

2) Gene Addition Delivers genes to provide a new function

Polygenic diseases e.g. cancer

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Were trying to make a mousecontraceptive vaccine for pest control

Used modified mousepox virus as

vehicle for transporting antibodies

into mice Inserted gene to create IL-4

(interleukin 4) to boost production

Surprise !!

totally suppressed the "cell-mediated

response which combats viral

infection

Mousepox 100% lethal

2001

8

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December 19, 2007

Boy gets leukaemia after gene treatment

to cure bubble baby syndrome

3 year-old with X-linked severe combined immunodeficiency

(X-SCID) - immune system fails to develop

Treated with genetically modified virus to correct the faulty DNA

that causes X-SCID

Inserting the replacement DNA activated another gene that

promotes cancer

Now an acknowledged risk of gene therapy

Also seen in 4 / 11 patients in a French trial

One has died while 3 are in remission

Retrovirus vector

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Regulations governing the handling

of gene therapy vectors

No additional regulations governing the

handling of Non-Infectious vectors

Non-viral & Non-bacterial

Viral vectors are Genetically Modified

Genetically Modified Organisms

(GMOs)

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Genetic Modification Genetic modification is officially defined

as the alteration of genetic material

(DNA or RNA) of an organism by means

that could not occur naturally through

mating and/or recombination

A guide to Genetically modified organisms (Contained Use)

Regulations 2000. Health and Safety Executive

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Regulations governing the handling

of gene therapy viral vectorsTwo sets of Regulations:

GMO (Contained Use) Regs 2000, HSE

All possible barriers (physical, biological or chemical) arein place to limit contact of the GMOs with humans and theenvironment

GMO (Deliberate Release) Regs 2002, DEFRA

All appropriate measures are taken to avoid damage to

the environm

ent from

the escape or release from

hum

ancontrol of GMOs

aimed at laboratories (difficult to interpret clinically)

no reference to product or patient safety

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Additional Regulations that apply to

Gene Therapy Clinical TrialsProtection of the Patient Gene Therapy Advisory Committee (GTAC)

Established 1993, Department of Health

UK national research ethics committee (REC) forgene therapy

Ethical acceptability for human gene therapy

Scientific merits

Potential benefits and risks

Patient flagging and long termmonitoring

Advice to UK health Ministers on developments ingene therapy research

Applies to ALL GENE THERAPY CLINICAL

TRIALS using viral and non-viral vectors

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Containment Measures Required

IsolatableLab Suite

MicrobiologicalSafety Cabinet

Gloves ProtectiveClothing

Class 1

Level 1

NO NO NO YES Requires first use ofpremises notification to

HSEClass 2Level 2

NO RiskAssessment

R/A

R/A YES Minimum requirement forany human bloodorclinical samples.

Requires HSE notification

Class 3

Level 3

YES YES YES YES

+ Footwear

Requires HSE notification

Class 4

Level 4

YES YES YES YESCompletechange of

clothing andfootwear on

entry and exit

Requires HSE notification

Containment Levels for GMOs

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Guidelines on Handling GMOs

in Pharmacy QA of Aseptic Preparation Services (4th Edn.)

Appendix 6 Gene Therapy

Scientific Advisory Committee on Genetic

Modification (SACGM), Part 6,Guidance on the use of genetically modified

micro-organisms in a clinical setting

European Association of Hospital Pharmacists (EAHP)Guidance on the Pharmacy Handling of Gene Medicines

Rules and Guidance forPharmaceutical

Manufacturers and Distributors 2007

No Specific Guidance

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APPENDIX 6 -

GENE THERAPY

Facilities

Documentation

Labelling

Training

Asepticprocessing

Cleaning

Storage

Transport

Waste

Disposal

Spillage

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Facilities Gene therapy should not be manipulated in

clinical areas

Basic Principles - Containment

- Knowledge/ understanding /skill- Validated procedures

Persons handling the product should be masked and gloved

All disposable equipment and materials used for prep & admin

- handled as biohazardous

Dedicated facilities required -ve pressure isolators orClass IIBSC

+ve pressure room or lobby

Contain

ment level > 2

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Clean roo

msuitedesigned to

provide protection

to the cleanroom

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Aseptic Manipulation

Doses Calculation/dilutions/multiple dilutions

Needle stick injury risk

Units

Particle Units/ml (PU/ml)

Plaque Forming Units/ml (PFU/ml)

Infectious particle Units/ml (IU/ml)

Gene Transfer Units/ml (GTU/ml)

Stability

Container compatibilities - Plastic/glassadhesion

Expiry date - Time to administration from thawing

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Decontamination Cleaning

Virucidal detergents (validated against GT vectors)

Cleaning Validation

Specific Detectionm

ethods needed for virusesthat are virus specific and highly sensitive

Waste Disposal

On site validated autoclave for re-usable

equipment Inactivation on-site forClass 3 vectors

Validated autoclave

Incineration

Disinfectant treatment

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Spillage

Specific to GT vector

Spillage kit Contents ( gloves, masks, aprons, goggles,

disposable shoe covers, virucidal detergents,

absorbent material, disposable forceps &

biohazard incineration bag)

Positioned in all GT handling areas

Notification to HSE

Accidental Exposure

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Risk Assessment Assess each product individually

Cytolytic viruses

Non-cytolytic viruses

Replication competent

Replication deficient Class I, II orIII

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What will the Future bring? Dedicated facilities

Automation?

The first gene medicine in Europe could belicensed in 2008

Licensed closed-system gene therapy products

Use of gene therapy as an adjunct to standardtherapy e.g. Radiotherapy & Chemotherapy

Vector development e.g. Targeted vectors (viral & non-viral)

Bacterial vectors

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Additional Information Gene Therapy Advisory Committee (GTAC)

http://www.advisorybodies.doh.gov.uk/genetics/gtac/index.htm

Gene therapy trials worldwide. Provided by the Journal of gene medicinehttp://82.182.180.141/trials/index.html

A guide to Genetically modified organisms (Contained Use) regulations2000. Health and Safety Executive

Genetically Modified Organism (Deliberate Release) Regulations 2002[GMO(DR)]. Department for the Environment, Food and Rural Affairs (DEFRA)http://www.opsi.gov.uk/si/si2002/uksi_20022443_en.pdf

Quality Assurance of Aseptic Preparation Services Fourth Edition.A.M.Beaney. Pharmaceutical Press 2006. Appendix 6. Gene Therapy.

EU Clinical Trials Directive.http://www.wctn.org.uk/downloads/EU_Directive/Directive.pdf

Implications of gene therapy for hospital pharmacists. Simpson.J, Stoner.N. www.pjonline.com/pdf/articles/ pj_20030726_genetherapy.pdf

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Additional Information Cancer gene therapy: from science to clinical trials. Searle. P.F, Spiers. I,

Simpson. J, James. J.D. Drug Delivery Systems and Sciences 2002, 2 (1), 5-13.

Standards for gene therapy clinical trials based on pro-active risk

assessment in a London NHS Teaching Hospital Trust. Bamford, K.B.,Wood, S., Shaw, R.J. QJM 2005, 98, 75-86. www.qjmed.oupjournals.org

Progress in Gene Therapy are hospital pharmacies the next barrier?Simpson, J. Hospital Pharmacist, 2006, 13 (8), 266http://www.pjonline.com/pdf/hp/200609/hp_200609_comment.pdf

Cancer Biotherapy. An Introductory guide. Young, A. Rowett, L. Kerr, D.Oxford University Press 2006

Scientific Advisory Committee on Genetic Modification (SACGM), Part 6,Guidance on the use of genetically modified microorganisms in a clinicalsetting. http://www.hse.gov.uk/biosafety/gmo/acgm/acgmcomp/part6.pdf

European Association of Hospital Pharmacists (EAHP) Guidance on thePharmacy Handling of Gene Medicines. http://www.ejhp.eu/