Presentation is loading. Please wait.

Presentation is loading. Please wait.

FDA Advisory Committee Meeting November 19, 2010 Findings and Challenges in Product Testing and Patient Monitoring for RCR/L in Gene Therapy Clinical Trials.

Similar presentations


Presentation on theme: "FDA Advisory Committee Meeting November 19, 2010 Findings and Challenges in Product Testing and Patient Monitoring for RCR/L in Gene Therapy Clinical Trials."— Presentation transcript:

1 FDA Advisory Committee Meeting November 19, 2010 Findings and Challenges in Product Testing and Patient Monitoring for RCR/L in Gene Therapy Clinical Trials Gwendolyn Binder-Scholl, Ph.D. University of Pennsylvania Translational Research Program

2 FDA Advisory Committee Meeting November 19, 2010 Overview Challenges of Biologic RCR/L Testing on Cell Products Summary of Retroviral Gene Therapy Trials in the TRP Detailed Testing Summaries for each Trial Discussion Points

3 FDA Advisory Committee Meeting November 19, 2010 Challenges biologic RCR/L testing on cell products Timing Increases enrollment-infusion time ~4-6 weeks (an alternative rapid method such as PCR may be used to provide an initial analysis when transduced patient cells must be administered immediately. But a culture based RCR/L assay should be initiated for retrospective confirmation). Cost cell manufacture ~$15K-$20K vector costs ~$15-30K per patient biological RCL testing is ~$22K Risk Theoretical and never observed

4 FDA Advisory Committee Meeting November 19, 2010 RCR/L Testing Summary 1 PA317 cell line unpublished 2 Lu et al, J. Gene Med., Zufferey et al, Nat. Biotech., 1997 IND Year open Vector typeTransgene Production Method RCR / RCL Vector RCR / RCL in Cells RCR / RCL in vivo Years follow-up MLVCD4-ζ CIR Producer cells 1 0/30/110/105-9yr cr-HIV HIV env antisense Transient transfection 2 0/70/200/181-4 yr SIN-HIVCD19-CIR Transient transfection 3 0/20/3 < SIN-HIV High affinity gag-TCR Transient transfection 3 0/1pending No RCR/L detected: 12 vector and 34 cell lots; 31 patients 3 different vector types and production systems: MLV, crHIV, sinHIV Up to 9 years follow-up in vivo

5 FDA Advisory Committee Meeting November 19, 2010 RCR Testing in IND 8568 (MLV) Clinical indication: HIV; CD4-zeta CIR Target cells: CD4 and CD8 T cells Vector and Cell product: Supernatant and cells cocultured with M. dunni cells -approximately 1% of total cell product/EOP and 300ml supernatant cocultured with M. dunni cells -+ control ( ffu amphotrophic MLV) -5 passages cell product (~3 weeks); 2 passages sup (~1-1.5 week) - test in feline PG-4 S + L - focus forming assay Patient Monitoring: -PCR amplification of a 70 bp region of the amphotrophic envelope in PBMCs -baseline, ~ quarterly to 1 year, and annually thereafter (protocol later modified to reflect current guidance on monitoring for delayed adverse events)

6 FDA Advisory Committee Meeting November 19, 2010 RCL Testing in IND (crHIV) Clinical indication: HIV; env antisense Target Cells: CD4 T cells Vector product: 5% final vector fill and 1% EOP cells at VIRxSYS Corporation in C cells -attenuated HIV positive control (Schonely et al, Bioprocessing J, 2003) Cell product: (no biologic RCL test) -PCR based assay for VSV-G envelope -PCR based assay monitoring HIV gag pre and post expansion Patient Monitoring: -PCR amplification for VSV-G envelope in PBMCs at a minimum quarterly and then annually (if negative at year 1, then archived for look back)

7 FDA Advisory Committee Meeting November 19, 2010 RCL Testing in IND (SIN-HIV) Clinical indication: HIV; HIV gag CTLs Target cells: CD8 T cells Vector product: 300ml sup and 1% EOP cells at Indiana University using the C cell line -R8.71 VSV-G pseudotyped attenuated HIV positive control Cell product: (no biologic RCL) -PCR based assay for VSV-G envelope Patient Monitoring: -PCR amplification for VSV-G envelope in PBMCs at a minimum quarterly and then annually (if negative at year 1, then archived for look back)

8 FDA Advisory Committee Meeting November 19, 2010 Molecular RCL Testing for Cell Product Release case study Day: CD820% CD4Harvest +vector VSV-G DNA RCL testing High affinity HIV gag TCR targeting SL9 epitope expressed by a SIN–HIV vector In consulation with FDA, determined no biologic RCL necessary: 1.ARV in media, no RCL amplification 2.CD4 T cells added after vector washout 3.Retroviruses are not stable at 37°C, losing 90% of titer each 48 hours (Higashikawa and Chang, Virology, 2001). Without amplification, residual RCL from the vector reduced 10,000 fold in 8 day culture. Fewer than 250 IU RCL are added to culture based on the LOD of the vector RCL assay. +ARV

9 FDA Advisory Committee Meeting November 19, 2010 Molecular RCL Testing on Cell Products case study-PCR sensitivity Testing 1% of cell product not feasible. The # of cells required to have 95% confidence that the sample is negative = 10,000 cells / 0.06 µg DNA Established test evaluates 450,000 cells / 3 µg DNA Adapt p=1-exp(-cV t ) : the probability of not detecting at least 1 RCR (FDA 2006 Supplemental Guidance on RCR testing)

10 FDA Advisory Committee Meeting November 19, 2010 Molecular RCL Testing on Cell Products case study-PCR sensitivity Assay can detect ≤ 50 VSV-G copies / µg genomic DNA: V t =-(1/50)ln(1-0.95) -FDA Guidance -Feasible LOD for a PCR assay -Empirically determined through spike and recovery studies V t =-(1/c)ln(1-p) Current Guidance -V t is the volume -c is the 1 IU/100ml -p is 95% confidence Adapted for DNA testing -V t is the ug of DNA (# cells) -c is 50 copies / ug genomic DNA (1:3000 cells) -p is 95% confidence

11 FDA Advisory Committee Meeting November 19, 2010 RCL Testing in IND (SIN-HIV) Clinical indication: CD19+ leukemia and lymphomas; CD19-CAR Target cells: CD4 and CD8 T cells Vector product: 300ml sup and 1% EOP cells at Indiana University using the C cell line Cell product: -p24 in T cell culture -PCR based assay for VSV-G envelope and HIV gag -Coculture of final product (1% or 1e8 cells) with C cells in method used in Escarpe et al, Mol Ther., 2006) -R8.71 positive control ~100 IU Patient Monitoring: -PCR amplification for HIV-gag in PBMCs at a minimum quarterly and then annually (if negative at year 1, then archived for look back)

12 FDA Advisory Committee Meeting November 19, 2010 Molecular RCL Testing on Cell Products IND Case Study Day: CD4/8Harvest +vector HIV gag DNA P24 VSV-G DNA Co-culture with C8166 cells RCL testing CD19-41BB-ζ CAR, expressed by a SIN–HIV vector Biological RCL assay because: 1.Antiretrovirals are not included in the culture media, 2.Spiking studies with R8.71 showed that 100 IU RCL could be carried through to the end of culture -not detectable by end of culture p24 -not detectable by amplification of end of culture supernatant with C8166 -detectable by co-culture with C8166 cells 3. The amount of vector used could theoretically contain >500 IU RCL given a LOD of 5 IU/ml from the vector RCL assay

13 FDA Advisory Committee Meeting November 19, 2010 Molecular RCL Testing on Cell Products IND Case Study-Residual vector protein/DNA p24 pg/ml Culture day HIVgag copies/µg Negative Cell population doubling Patient 1Patient 2Patient 3

14 FDA Advisory Committee Meeting November 19, 2010 Discussion Points 1.Not all cell manufacturing processes are equal. When might biologic RCL testing for cell products be informative?: -when using vectors with high levels of residual packaging DNA/protein -addition of high amounts of vector (low titer) 2.Biological RCL testing on cell products is a major burden. Potential solutions are: a. Use molecular approaches for RCR/L testing on cell products-in which cases would this be acceptable? b. Develop a funding initiative to defray the costs associated with amplification based RCR/L testing, or, c. Establish discounted services to perform amplification based RCL testing (such as the NGVL initiative) 3.FDA Guidance for RCR/L annual archive could follow current guidance for monitoring for delayed adverse events. If gene modified cells no longer detected at 5 year, no RCR/L sample collection for archive should be required.

15 FDA Advisory Committee Meeting November 19, 2010 Acknowledgements University of PennsylvaniaCity of Hope, Center for Biomedicine & Genetics Carl JuneLarry Couture Bruce LevineDavid Hsu Zoe Zheng Cell GenesysNIH, NIAID Kristen HegeSarah Read Mitch FinerFrosso Voulgaropoulou Sandra Bridges VIRxSYSU19 AI Gerard McGarrityU19 AI Laurent Humeau Alliance for Cancer Gene Therapy Lentigen Boro Dropulic


Download ppt "FDA Advisory Committee Meeting November 19, 2010 Findings and Challenges in Product Testing and Patient Monitoring for RCR/L in Gene Therapy Clinical Trials."

Similar presentations


Ads by Google