Gene Therapy - Problems and Challenges

1
Gene Therapy - Problems and Challenges
Helapet Aseptic Study Day 2008

• Alison M. Beaney
• Regional Quality Assurance Specialist
• North-East and Yorkshire

2
Gene Therapy

• Background to Gene Therapy
• Potential Benefits
• Perceived Hazards and Risks
• Regulations
• Implications for Pharmacy Aseptic Units
• Future?

2
3
Gene Therapy

• Definition
• The deliberate introduction of genetic material
  into human somatic cells for therapeutic,
  prophylactic or 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
  patient was in 1989
• First gene therapy product approved for market in
  2004
• Still very experimental and early in its
  development

3
4
PTQA April 2008
4
5
Gene Therapy Vectors

• Vectors deliver genes to cells

5
6
Types of Gene Therapy Vectors

• Non-viral vectors
• Naked DNA
• Liposomes/DNA
• Polymer/DNA complex (polyplex)
• Liposome/Polymer/DNA (lipopolyplex)

• Viral vectors
• DNA viruses
• Adenovirus
• Herpes Simplex Virus
• RNA viruses
• Retrovirus

6
7
Gene Therapy Strategies

• 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
• Gene Addition
• Delivers genes to provide a new function
• Polygenic diseases e.g. cancer

7
8
2001

• Were trying to make a mouse contraceptive 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

8
9

• 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
10
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)

10
11
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

11
12
Regulations governing the handling of gene
therapy viral vectors

• Two sets of Regulations
• GMO (Contained Use) Regs 2000, HSE
• All possible barriers (physical, biological or
  chemical) are in place to limit contact of the
  GMOs with humans and the environment
• GMO (Deliberate Release) Regs 2002, DEFRA
• All appropriate measures are taken to avoid
  damage to the environment from the escape or
  release from human control of GMOs
• aimed at laboratories (difficult to interpret
  clinically)
• no reference to product or patient safety

12
13
Additional Regulations that apply to Gene Therapy
Clinical Trials

• Protection of the Patient
• Gene Therapy Advisory Committee (GTAC)
• Established 1993, Department of Health
• UK national research ethics committee (REC) for
  gene therapy
• Ethical acceptability for human gene therapy
• Scientific merits
• Potential benefits and risks
• Patient flagging and long term monitoring
• Advice to UK health Ministers on developments in
  gene therapy research
• Applies to ALL GENE THERAPY CLINICAL TRIALS using
  viral and non-viral vectors

13
14
Containment Levels for GMOs
Containment Measures Required Containment Measures Required Containment Measures Required Containment Measures Required
Isolatable Lab Suite Microbiological Safety Cabinet Gloves Protective Clothing
Class 1 Level 1 NO NO NO YES Requires first use of premises notification to HSE
Class 2 Level 2 NO Risk Assessment R/A R/A YES Minimum requirement for any human blood or clinical samples. Requires HSE notification
Class 3 Level 3 YES YES YES YES Footwear Requires HSE notification
Class 4 Level 4 YES YES YES YES Complete change of clothing and footwear on entry and exit Requires HSE notification
15
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 for Pharmaceutical
  Manufacturers and Distributors 2007
  No Specific Guidance

15
16
APPENDIX 6 - GENE THERAPY

• Facilities
• Documentation
• Labelling
• Training
• Aseptic processing

• Cleaning
• Storage
• Transport
• Waste Disposal
• Spillage

16
17
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 or Class II BSC
• ve pressure room or lobby
• Containment level gt 2

17
18
Clean room suite designed to provide protection
to the cleanroom
19
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/glass
  adhesion
• Expiry date - Time to administration from thawing

19
20
Decontamination

• Cleaning
• Virucidal detergents (validated against GT
  vectors)
• Cleaning Validation
• Specific Detection methods needed for viruses
  that are virus specific and highly sensitive
• Waste Disposal
• On site validated autoclave for re-usable
  equipment
• Inactivation on-site for Class 3 vectors
• Validated autoclave
• Incineration
• Disinfectant treatment

20
21
Accidental Exposure

• 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

21
22
SOPs needed

• Safe handling protection
• Storage
• Operators (Not pregnant, breastfeeding or
  immunosuppressed)
• Training
• Facilities
• Spillage, contamination needle stick
• Waste disposal, cleaning and transport

22
23
Risk Assessment

• Assess each product individually
• Cytolytic viruses
• Non-cytolytic viruses
• Replication competent
• Replication deficient
• Class I, II or III

23
24
What will the Future bring?

• Dedicated facilities
• Automation?
• The first gene medicine in Europe could be
  licensed in 2008
• Licensed closed-system gene therapy products
• Use of gene therapy as an adjunct to standard
  therapy e.g. Radiotherapy Chemotherapy
• Vector development e.g.
• Targeted vectors (viral non-viral)
• Bacterial vectors

24
25
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 medicine http//82.182.180.141/tri
  als/index.html
• A guide to Genetically modified organisms
  (Contained Use) regulations 2000. 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_2002
  2443_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_genethe
  rapy.pdf

25
26
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), 266 http//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
  clinical setting. http//www.hse.gov.uk/biosafety/
  gmo/acgm/acgmcomp/part6.pdf
• European Association of Hospital Pharmacists
  (EAHP) Guidance on the Pharmacy Handling of Gene
  Medicines. http//www.ejhp.eu/

26