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Gene Therapy


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Gene Therapy

  1. 1. Gene Therapy - Problems and Challenges <ul><li>Alison M. Beaney </li></ul><ul><li>Regional Quality Assurance Specialist </li></ul><ul><li>North-East and Yorkshire </li></ul>Helapet Aseptic Study Day 2008
  2. 2. Gene Therapy <ul><li>Background to Gene Therapy </li></ul><ul><li>Potential Benefits </li></ul><ul><li>Perceived Hazards and Risks </li></ul><ul><li>Regulations </li></ul><ul><li>Implications for Pharmacy Aseptic Units </li></ul><ul><li>Future? </li></ul>
  3. 3. Gene Therapy <ul><li>Definition </li></ul><ul><li>The deliberate introduction of genetic material into human somatic cells for therapeutic, prophylactic or diagnostic purposes </li></ul><ul><ul><li>Addition of EXTRA genes </li></ul></ul><ul><ul><li>Aim is to cure disease (or at least help the patient) </li></ul></ul><ul><ul><li>First introduction of gene-modified cells into a patient was in 1989 </li></ul></ul><ul><ul><li>First gene therapy product approved for market in 2004 </li></ul></ul><ul><li>Still very experimental and early in its development </li></ul>
  4. 4. PTQA April 2008
  5. 5. Gene Therapy Vectors <ul><li>Vectors deliver genes to cells </li></ul>Therapeutic gene (Transgene) Therapeutic protein Vector for efficient gene delivery Transcription Translation
  6. 6. Types of Gene Therapy Vectors <ul><li>Non-viral vectors </li></ul><ul><ul><li>Naked DNA </li></ul></ul><ul><ul><li>Liposomes/DNA </li></ul></ul><ul><ul><li>Polymer/DNA complex (polyplex) </li></ul></ul><ul><ul><li>Liposome/Polymer/DNA (lipopolyplex) </li></ul></ul><ul><li>Viral vectors </li></ul><ul><ul><li>DNA viruses </li></ul></ul><ul><ul><ul><li>Adenovirus </li></ul></ul></ul><ul><ul><ul><li>Herpes Simplex Virus </li></ul></ul></ul><ul><ul><li>RNA viruses </li></ul></ul><ul><ul><ul><li>Retrovirus </li></ul></ul></ul>
  7. 7. Gene Therapy Strategies <ul><li>Gene Replacement </li></ul><ul><ul><li>Replace ‘faulty’ genes with normal genes </li></ul></ul><ul><ul><li>Corrects inherited genetic errors </li></ul></ul><ul><ul><li>Provides a missing function </li></ul></ul><ul><ul><li>Monogenic diseases e.g. cystic fibrosis, haemophilia, X-SCID </li></ul></ul><ul><li>Gene Addition </li></ul><ul><ul><li>Delivers genes to provide a new function </li></ul></ul><ul><ul><li>Polygenic diseases e.g. cancer </li></ul></ul>
  8. 8. <ul><li>Were trying to make a mouse contraceptive vaccine for pest control </li></ul><ul><li>Used modified mousepox virus as vehicle for transporting antibodies into mice </li></ul><ul><li>Inserted gene to create ↑ IL-4 (interleukin 4) to boost production </li></ul><ul><li>Surprise !! </li></ul><ul><li>totally suppressed the &quot;cell-mediated response“ which combats viral infection </li></ul><ul><li>Mousepox 100% lethal </li></ul>2001
  9. 9. <ul><li> December 19, 2007 </li></ul><ul><li>Boy gets leukaemia after gene treatment to cure ‘bubble baby syndrome’ </li></ul><ul><li>3 year-old with X-linked severe combined immunodeficiency (X-SCID) - immune system fails to develop </li></ul><ul><li>Treated with genetically modified virus to correct the faulty DNA that causes X-SCID </li></ul><ul><li>Inserting the replacement DNA activated another gene that promotes cancer </li></ul><ul><li>Now an acknowledged risk of gene therapy </li></ul><ul><li> Also seen in 4 / 11 patients in a French trial One has died while 3 are in remission </li></ul>Retrovirus vector
  10. 10. Regulations governing the handling of gene therapy vectors <ul><li>No additional regulations governing the handling of Non-Infectious vectors </li></ul><ul><ul><li>Non-viral & Non-bacterial </li></ul></ul><ul><li>Viral vectors are Genetically Modified </li></ul><ul><li>Genetically Modified Organisms (GMOs) </li></ul>
  11. 11. Genetic Modification <ul><li>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’ </li></ul><ul><li>A guide to Genetically modified organisms (Contained Use) Regulations 2000. Health and Safety Executive </li></ul>
  12. 12. Regulations governing the handling of gene therapy viral vectors <ul><li>Two sets of Regulations: </li></ul><ul><ul><li>GMO (Contained Use) Regs 2000, HSE </li></ul></ul><ul><ul><ul><li>All possible barriers (physical, biological or chemical) are in place to limit contact of the GMOs with humans and the environment </li></ul></ul></ul><ul><ul><li>GMO (Deliberate Release) Regs 2002 , DEFRA </li></ul></ul><ul><ul><ul><li>All appropriate measures are taken to avoid damage to the environment from the escape or release from human control of GMOs </li></ul></ul></ul><ul><ul><li>aimed at laboratories (difficult to interpret clinically) </li></ul></ul><ul><ul><li>no reference to product or patient safety </li></ul></ul>
  13. 13. Additional Regulations that apply to Gene Therapy Clinical Trials <ul><li>Protection of the Patient </li></ul><ul><ul><li>Gene Therapy Advisory Committee (GTAC) </li></ul></ul><ul><ul><ul><li>Established 1993, Department of Health </li></ul></ul></ul><ul><ul><ul><li>UK national research ethics committee (REC) for gene therapy </li></ul></ul></ul><ul><ul><ul><ul><li>Ethical acceptability for human gene therapy </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Scientific merits </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Potential benefits and risks </li></ul></ul></ul></ul><ul><ul><ul><li>Patient flagging and long term monitoring </li></ul></ul></ul><ul><ul><ul><li>Advice to UK health Ministers on developments in gene therapy research </li></ul></ul></ul><ul><ul><ul><li>Applies to ALL GENE THERAPY CLINICAL TRIALS using viral and non-viral vectors </li></ul></ul></ul>
  14. 14. Containment Levels for GMOs 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. 15. Guidelines on Handling GMOs in Pharmacy <ul><li>QA of Aseptic Preparation Services (4th Ed n. ) Appendix 6 Gene Therapy </li></ul><ul><li>Scientific Advisory Committee on Genetic Modification (SACGM), Part 6, Guidance on the use of genetically modified micro-organisms in a clinical setting </li></ul><ul><li>European Association of Hospital Pharmacists (EAHP) Guidance on the Pharmacy Handling of Gene Medicines </li></ul><ul><li>Rules and Guidance for Pharmaceutical Manufacturers and Distributors 2007 – No Specific Guidance </li></ul>
  16. 16. APPENDIX 6 - GENE THERAPY <ul><li>Facilities </li></ul><ul><li>Documentation </li></ul><ul><li>Labelling </li></ul><ul><li>Training </li></ul><ul><li>Aseptic processing </li></ul><ul><li>Cleaning </li></ul><ul><li>Storage </li></ul><ul><li>Transport </li></ul><ul><li>Waste Disposal </li></ul><ul><li>Spillage </li></ul>
  17. 17. Facilities <ul><ul><li>Gene therapy should not be manipulated in clinical areas </li></ul></ul><ul><ul><li>Basic Principles - Containment - Knowledge / understanding / skill - Validated procedures </li></ul></ul><ul><ul><ul><li>Persons handling the product should be masked and gloved </li></ul></ul></ul><ul><ul><ul><li>All disposable equipment and materials used for prep & admin - handled as biohazardous </li></ul></ul></ul><ul><li>Dedicated facilities required </li></ul><ul><ul><li>-ve pressure isolators or Class II BSC </li></ul></ul><ul><ul><li>+ve pressure room or lobby </li></ul></ul><ul><ul><li>Containment level > 2 </li></ul></ul>
  18. 18. Clean room suite designed to provide protection to the cleanroom
  19. 19. Aseptic Manipulation <ul><ul><li>Doses </li></ul></ul><ul><ul><ul><li>Calculation / dilutions / multiple dilutions </li></ul></ul></ul><ul><ul><ul><li>Needle stick injury risk </li></ul></ul></ul><ul><ul><ul><li>Units </li></ul></ul></ul><ul><ul><ul><ul><li>Particle Units/ml (PU/ml) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Plaque Forming Units/ml (PFU/ml) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Infectious particle Units/ml (IU/ml) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Gene Transfer Units/ml (GTU/ml) </li></ul></ul></ul></ul><ul><ul><li>Stability </li></ul></ul><ul><ul><ul><li>Container compatibilities - Plastic/glass adhesion </li></ul></ul></ul><ul><ul><ul><li>Expiry date - Time to administration from thawing </li></ul></ul></ul>
  20. 20. Decontamination <ul><li>Cleaning </li></ul><ul><ul><li>Virucidal detergents (validated against GT vectors) </li></ul></ul><ul><ul><ul><li>Cleaning Validation </li></ul></ul></ul><ul><ul><ul><ul><li>Specific Detection methods needed for viruses that are virus specific and highly sensitive </li></ul></ul></ul></ul><ul><li>Waste Disposal </li></ul><ul><ul><ul><li>On site validated autoclave for re-usable equipment </li></ul></ul></ul><ul><ul><ul><li>Inactivation on-site for Class 3 vectors </li></ul></ul></ul><ul><ul><ul><ul><li>Validated autoclave </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Incineration </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Disinfectant treatment </li></ul></ul></ul></ul>
  21. 21. <ul><li>Spillage </li></ul><ul><ul><li>Specific to GT vector </li></ul></ul><ul><ul><li>Spillage kit </li></ul></ul><ul><ul><ul><li>Contents ( gloves, masks, aprons, goggles, disposable shoe covers, virucidal detergents, absorbent material, disposable forceps & biohazard incineration bag) </li></ul></ul></ul><ul><ul><ul><li>Positioned in all GT handling areas </li></ul></ul></ul><ul><ul><ul><li>Notification to HSE </li></ul></ul></ul>Accidental Exposure
  22. 22. SOPs needed <ul><ul><li>Safe handling & protection </li></ul></ul><ul><ul><li>Storage </li></ul></ul><ul><ul><li>Operators (Not pregnant, breastfeeding or immunosuppressed) </li></ul></ul><ul><ul><li>Training </li></ul></ul><ul><ul><li>Facilities </li></ul></ul><ul><ul><li>Spillage, contamination & needle stick </li></ul></ul><ul><ul><li>Waste disposal, cleaning and transport </li></ul></ul>
  23. 23. Risk Assessment <ul><li>Assess each product individually </li></ul><ul><ul><li>Cytolytic viruses </li></ul></ul><ul><ul><li>Non-cytolytic viruses </li></ul></ul><ul><ul><li>Replication competent </li></ul></ul><ul><ul><li>Replication deficient </li></ul></ul><ul><ul><li>Class I, II or III </li></ul></ul>
  24. 24. What will the Future bring? <ul><ul><li>Dedicated facilities </li></ul></ul><ul><ul><li>Automation? </li></ul></ul><ul><ul><li>The first gene medicine in Europe could be licensed in 2008 </li></ul></ul><ul><ul><li>Licensed closed-system gene therapy products </li></ul></ul><ul><ul><li>Use of gene therapy as an adjunct to standard therapy e.g. Radiotherapy & Chemotherapy </li></ul></ul><ul><ul><li>Vector development e.g. </li></ul></ul><ul><ul><ul><ul><li>Targeted vectors (viral & non-viral) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Bacterial vectors </li></ul></ul></ul></ul>
  25. 25. Additional Information <ul><li>Gene Therapy Advisory Committee (GTAC) http://www. advisorybodies . doh . gov . uk /genetics/ gtac /index. htm </li></ul><ul><li>Gene therapy trials worldwide. Provided by the Journal of gene medicine </li></ul><ul><li>A guide to Genetically modified organisms (Contained Use) regulations 2000. Health and Safety Executive </li></ul><ul><li>Genetically Modified Organism (Deliberate Release) Regulations 2002 [GMO(DR)]. Department for the Environment, Food and Rural Affairs (DEFRA) </li></ul><ul><li>Quality Assurance of Aseptic Preparation Services Fourth Edition. A.M. Beaney. Pharmaceutical Press 2006. Appendix 6. Gene Therapy. </li></ul><ul><li>EU Clinical Trials Directive. http://www. wctn .org. uk /downloads/EU_Directive/Directive. pdf </li></ul><ul><li>Implications of gene therapy for hospital pharmacists. Simpson.J, Stoner. N. pj_20030726_ genetherapy .pdf </li></ul>
  26. 26. Additional Information <ul><li>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. </li></ul><ul><li>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 </li></ul><ul><li>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 </li></ul><ul><li>Cancer Biotherapy. An Introductory guide. Young, A. Rowett, L. Kerr, D. Oxford University Press 2006 </li></ul><ul><li>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 </li></ul><ul><li>European Association of Hospital Pharmacists (EAHP) Guidance on the Pharmacy Handling of Gene Medicines. http://www. ejhp . eu / </li></ul>