Long Term Follow Up of Subjects in Gene Transfer Clinical Trials

1. Long Term Follow Up of Subjects in Gene Transfer Clinical Trials Philippe Bishop, MD FDA/CBER Division of Clinical Trial Design and Analysis Oncology Branch

2. September 20, 1993 Letter to Sponsors • RCR related lymphoma in Rhesus monkeys (Donahue RE et al, J Exp Med 176:1125, 1992) • Limited clinical experience with retroviral vectors

3. Clinical exposure to integrating vectors may pose risks to subjects that may not become apparent until years later. De novo cancer Autoimmune disease Hematologic disorders Neurologic disorders Life Long Monitoring:A Key Principle

4. Testing for Replication Competent Retrovirus in Retroviral Vector Based Gene Therapy Products and During Follow-up of Patients in Clinical Trials using Retroviral Vectors. http://www.fda.gov/cber/guidelines.htm October 18, 2000 Guidance Document

5. Current RecommendationsAssays • RCR-specific antibodies or • PCR for RCR-specific sequences in peripheral blood mononuclear cells

6. Current RecommendationsTesting Schedule • Pre-treatment • 3 months • 6 months • 1 year after treatment • Yearly thereafter

7. Current RecommendationsTesting Schedule (continued) • Yearly archival if samples are negative for RCR for 1 year post-treatment • Additional testing and patient follow-up if clinically indicated and/or sample is positive for RCR.

8. Current RecommendationsClinical Follow-up • Yearly clinical history • Cancer • Neurologic disorders • Hematologic disorders • Suspect clinical outcomes may trigger additional analysis of archived samples

9. Current RecommendationsClinical Follow-up (continued) If a study participant • Develops de novo neoplasm • Neoplastic tissue should be tested for RCR • Dies • An autopsy should be obtained and sampled tissue tested for RCR.

10. Current RecommendationsDocumentation Expedited reports (21 CFR 312.32) • Positive results (laboratory or clinical) Annual Reports (21 CFR 312.33) • Other laboratory data • Clinical summaries • Autopsy results

11. Sponsors were contacted and asked to comment on their experience implementing life long monitoring protocols Retroviral Vector Gene TherapyFDA Survey

12. Retroviral Vector Gene TherapyLong-Term Monitoring Survey • 89% of INDs have an established long-term follow-up protocol

13. Sponsor’s Comments to FDACosts • Estimates: $1,500-$5,000/patient/year • Inadequate resources (limited grants) • Sub-optimal 3rd party reimbursement

14. Sponsor’s Comments to FDAClinical follow-up • Study participants move • Geographic distance • Patient and referring MD lose interest • Inadequate reporting (MD to PI; PI to Sponsor)

15. Sponsor’s Comments to FDACommitment • PI moves to another institution • PI leaves academia to private sector/industry • Industry mergers/Bankruptcy • Sponsor/Institution reluctant to devote indefinite resources (program closure)

16. Long-Term Monitoring SurveyAutopsies • Most patients die at home or away from research centers • PIs are not notified in time • Families are not asked or decline to consent • Sampling for RCR is not performed or specimen collection is sub-optimal

17. Long-Term Monitoring SurveyAssays/Testing methods • Lack of standardization (core facility?) • Sensitivity • Validation • Clinical relevance: (ex vivo vs in vivo gene transfer studies)

18. Administrative ActionsAssurance of Continued Monitoring • IND Inactivation or withdrawal • 15% of INDs • Sponsor committed to annual follow-up of patients • FDA will accept expedited and annual reports

19. Enforcement Options Clinical Hold Site visit/inspection Warning letter Disqualification

20. Summary • Updated guidance document • Sponsors expressed concerns that life long monitoring is • Logistically difficult, • Costly, and • Requires an unusual level of commitment. • FDA’s enforcement options are limited.