Absence of Replication-Competent Retrovirus in Vectors, T Cell Products, and Patient Follow-Up Samples
Authors: Deborah Lyon, Natasha Lapteva, Adrian P. Gee
Journal: Molecular Therapy (2017)

Two papers published in this issue of Molecular Therapy report on the results of testing for replication-competent lentivirus (RCL) or retrovirus (RCR) in the vector product as well as the infused vector-transduced T cell lines and patient follow-up samples in recipients of genetically modified T cells.1Cornetta K. Duffy L. Turtle C.J. Jensen M. Forman S. Binder-Scholl G. Fry T. Chew A. Maloney D.G. June C.H. Absence of Replication-Competent Lentivirus in the Clinic: Analysis of Infused T Cell Products.Mol. Ther. 2017; 26 (this issue): 280-288Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar, 2Marcucci K.T. Jadlowsky J.K. Hwang W.-T. Suhoski-Davis M. Gonzalez V.E. Kulikovskaya I. Gupta M. Lacey S.F. Plesa G. Chew A. et al.Retroviral and Lentiviral Safety Analysis of Gene-Modified T Cell Products and Infused HIV and Oncology Patients.Mol. Ther. 2017; 26 (this issue): 269-279Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar In the first study, the National Gene Vector Biorepository (NGVB) reports results from 26 trials using third-generation lentiviral vectors produced by transient transfection and that all assays for RCL in vector lots, 460 infused products, and 296 follow-up samples from patients were negative.1Cornetta K. Duffy L. Turtle C.J. Jensen M. Forman S. Binder-Scholl G. Fry T. Chew A. Maloney D.G. June C.H. Absence of Replication-Competent Lentivirus in the Clinic: Analysis of Infused T Cell Products.Mol. Ther. 2017; 26 (this issue): 280-288Abstract Full Text Full Text PDF PubMed Scopus (66) Google Scholar In the second report, investigators at the University of Pennsylvania reported data for 17 vector lots, 375 manufactured T cell products, and 308 patient follow-up samples, showing no evidence of RCR/L.2Marcucci K.T. Jadlowsky J.K. Hwang W.-T. Suhoski-Davis M. Gonzalez V.E. Kulikovskaya I. Gupta M. Lacey S.F. Plesa G. Chew A. et al.Retroviral and Lentiviral Safety Analysis of Gene-Modified T Cell Products and Infused HIV and Oncology Patients.Mol. Ther. 2017; 26 (this issue): 269-279Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar Both groups concluded that, with this body of safety testing, it may be appropriate to re-evaluate the current guidelines for T cell gene therapy product testing and long-term patient monitoring. In 2012, the experience of our group with RCR testing of vector products, transduced cell lines, and patient samples was included in a multicenter report that detailed negative testing on 297 infused T cell lines and 629 patient follow-up samples.3Bear A.S. Morgan R.A. Cornetta K. June C.H. Binder-Scholl G. Dudley M.E. Feldman S.A. Rosenberg S.A. Shurtleff S.A. Rooney C.M. et al.Replication-competent retroviruses in gene-modified T cells used in clinical trials: is it time to revise the testing requirements?.Mol. Ther. 2012; 20: 246-249Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar Here we present updated data that includes testing performed in the last 6 years and not reported in our previous publication. As summarized in Table 1 we have manufactured vectors for 17 clinical trials, using 9 different retroviral constructs where we have tested 9 lots. A total of 266 cell lines have been manufactured, and all have tested negative for RCR using a co-culture assay. 220 patients have been infused with these products and have had follow-up RCR assays run by the NGVB in the first year post infusion, with subsequent follow-up assays archived. A total of 549 patient samples have been assayed, and all have been negative.Table 1Testing Results for RCRClinical Trial NoRetroviral VectorVector Supernatant ResultsCell Line ResultsPatient Follow-Up ResultsNCT00368082NCT02379520NCT02065362TGF-β RIIdcyt (DNRII)negative17 negative5 negative7 negative54 negative4 negative15 negativeNCT005863914Savoldo B. Ramos C.A. Liu E. Mims M.P. Keating M.J. Carrum G. Kamble R.T. Bollard C.M. Gee A.P. Mei Z. et al.CD28 costimulation improves expansion and persistence of chimeric antigen receptor-modified T cells in lymphoma patients.J. Clin. Invest. 2011; 121: 1822-1826Crossref PubMed Scopus (767) Google ScholarCAR-CD19. CD28. ζ andCAR-CD19. ζnegative27 negative37 negativeNCT01853631CAR-CD19. CD28. ζ andCAR-CD19.41BB .CD28. Ζnegative34 negative33 negativeNCT007108925Di Stasi A. Tey S.K. Dotti G. Fujita Y. Kennedy-Nasser A. Martinez C. Straathof K. Liu E. Durett A.G. Grilley B. et al.Inducible apoptosis as a safety switch for adoptive cell therapy.N. Engl. J. Med. 2011; 365: 1673-1683Crossref PubMed Scopus (1047) Google ScholarNCT014941036Zhou X. Dotti G. Krance R.A. Martinez C.A. Naik S. Kamble R.T. Durett A.G. Dakhova O. Savoldo B. Di Stasi A. et al.Inducible caspase-9 suicide gene controls adverse effects from alloreplete T cells after haploidentical stem cell transplantation.Blood. 2015; 125: 4103-4113Crossref PubMed Scopus (154) Google ScholariCaspase9. ACD19negative11 negative14 negative33 negative26 negativeNCT02050347 NCT008408537Cruz C.R. Micklethwaite K.P. Savoldo B. Ramos C.A. Lam S. Ku S. Diouf O. Liu E. Barrett A.J. Ito S. et al.Infusion of donor-derived CD19-redirected virus-specific T cells for B-cell malignancies relapsed after allogeneic stem cell transplant: a phase 1 study.Blood. 2013; 122: 2965-2973Crossref PubMed Scopus (401) Google ScholarCAR-CD19.CD28. ζnegative6 negative21 negative10 negative50 negativeNCT00889954CAR-HER2. CD28. ζ TGFβ RIIdcyt (DNRII)negative22 negative42 negativeNCT009020448Ahmed N. Brawley V.S. Hegde M. Robertson C. Ghazi A. Gerken C. Liu E. Dakhova O. Ashoori A. Corder A. et al.Human Epidermal Growth Factor Receptor 2 (HER2) -Specific Chimeric Antigen Receptor-Modified T Cells for the Immunotherapy of HER2-Positive Sarcoma.J. Clin. Oncol. 2015; 33: 1688-1696Crossref PubMed Scopus (663) Google ScholarNCT011090959Ahmed N. Brawley V. Hegde M. Bielamowicz K. Kalra M. Landi D. Robertson C. Gray T.L. Diouf O. Wakefield A. et al.HER2-Specific Chimeric Antigen Receptor-Modified Virus-Specific T Cells for Progressive Glioblastoma: A Phase 1 Dose-Escalation Trial.JAMA Oncol. 2017; 3: 1094-1101Crossref PubMed Scopus (428) Google ScholarCAR-HER2. CD28. ζnegative26 negative18 negative68 negative35 negativeNCT01192464 NCT0131614610Ramos C.A. Ballard B. Zhang H. Dakhova O. Gee A.P. Mei Z. Bilgi M. Wu M.F. Liu H. Grilley B. et al.Clinical and immunological responses after CD30-specific chimeric antigen receptor-redirected lymphocytes.J. Clin. Invest. 2017; 127: 3462-3471Crossref PubMed Scopus (245) Google ScholarCAR-CD30. CD28. ζnegative4 negative10 negative10 negative37 negativeNCT0088192011Ramos C.A. Savoldo B. Torrano V. Ballard B. Zhang H. Dakhova O. Liu E. Carrum G. Kamble R.T. Gee A.P. et al.Clinical responses with T lymphocytes targeting malignancy-associated κ light chains.J. Clin. Invest. 2016; 126: 2588-2596Crossref PubMed Scopus (211) Google ScholarCAR-Kappa.CD28. ζnegative17 negative49 negativeNCT0182265212Heczey A. Louis C.U. Savoldo B. Dakhova O. Durett A. Grilley B. Liu H. Wu M.F. Mei Z. Gee A. et al.CAR T Cells Administered in Combination with Lymphodepletion and PD-1 Inhibition to Patients with Neuroblastoma.Mol. Ther. 2017; 25: 2214-2224Abstract Full Text Full Text PDF PubMed Scopus (293) Google ScholarNCT01953900CAR-GD2.CD28. OX40. ζnegative18 negative9 negative31 negative15 negativeTotal–9 negative266 negative549 negative Open table in a new tab These data presented on RCR testing supplement our previous report and support the data on RCL testing presented in the two papers in this issue, which suggest that RCR/RCL testing of the transduced lines and patient follow-up samples are no longer needed if the viral vector supernatant used to genetically modify the T cells initially tested negative for replication-competent virus. D.L. supervised the RCR assays and collated the data. N.L. and A.P.G. provided QA review. All authors reviewed the letter. This work was supported by the National Cancer Institute (P50CA126752 and P01CA094237) and the Leukemia and Lymphoma Society. The clinical trials also received support from the shared resources of the Dan L. Duncan Cancer Center support grant (5P30CA125123) and the National Gene Vector Biorepository.