Gene Therapy for Fanconi Anemia [Group A]: Interim Results of RP-L102 Clinical Trials

Abstract

▪Background: Fanconi anemia (FA) is a disorder of defective deoxyribonucleic acid (DNA) repair, progressive bone marrow failure (BMF), and a predisposition to hematologic malignancies and solid tumors. Approximately 60 to 70% of all cases result from a mutation in the Fanconi Anemia Complementation Group A (FANCA) gene (FA-A). 80% of FA patients experience BMF within the first decade of life. Allogeneic hematopoietic stem cell transplant (alloHSCT) is potentially curative for BMF; however, its efficacy is limited by human leukocyte antigen (HLA)-matched sibling donor availability and transplant-related toxicities. Lentiviral mediated gene therapy utilizing autologous FA-A CD34+ enriched hematopoietic stem and progenitor cells (HSPCs) confers a proliferative advantage to gene-corrected HSPCs as demonstrated in preclinical studies and the FANCOLEN-I clinical trial conducted in Madrid, Spain. We report results from ongoing RP-L102 studies using “Process B” manufacturing optimizations including transduction enhancers, commercial grade vector, and modified cell processing.Methods: Patients (pts) with a FANCA gene mutation, age ≥1 year with no HLA-matched sibling donor and at least 30 CD34+ cells/µL in bone marrow (BM) are eligible. Peripheral blood (PB) mononuclear cells are collected via leukapheresis on 2 consecutive days after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. CD34+ HSPCs are enriched, transduced with a lentiviral vector encoding for the FANCA gene (PGK-FANCA-WPRE) and infused without cryopreservation or conditioning. Patients are followed for 3 years post-infusion for safety assessments (replication competent lentivirus [RCL], insertion site analysis [ISA]) and to ascertain evidence of efficacy (increasing PB and BM vector copy number [VCN] and mitomycin-C [MMC] resistance in BM colony forming units [CFUs]), along with stabilization/correction of cytopenias.Results: As of March 2021, 9 pts (aged 2 to 6 years) have received RP-L102. Evidence of engraftment has been identified in 6 pts with ≥6 months of follow up as indicated by PB VCN. 2 of 3 pts with follow up of ≥12 months have shown increased MMC resistance in BM CFUs. 1 pt developed BMF requiring alloHSCT after influenza B infection. 1 pt had a serious Grade 2 transient RP-L102 infusion-related reaction. Updated safety and efficacy data for pts with ≥12 months of follow-up will be presented.Conclusions: RP-L102's safety profile remains favorable. Increasing evidence of engraftment has been confirmed in 6 subjects as demonstrated by PB VCN; without conditioning, 12+ months of follow up is likely required to observe the proliferative advantage of transduced HSPCs. DisclosuresCzechowicz: Editas Medicine: Current equity holder in publicly-traded company; Rocket Pharmaceuticals, Inc.: Research Funding; Global Blood Therapeutics: Current equity holder in publicly-traded company; Stemodontics: Consultancy, Current equity holder in publicly-traded company; GV: Consultancy, Current equity holder in publicly-traded company; Spotlight Therapeutics: Consultancy, Current equity holder in publicly-traded company; Beam Therapeutics: Consultancy, Current equity holder in publicly-traded company; Magenta Therapeutics: Current equity holder in publicly-traded company, Other: Intellectual property rights; Decibel Therapeutics: Current equity holder in publicly-traded company; Forty Seven Inc.: Divested equity in a private or publicly-traded company in the past 24 months; Gilead Sciences: Other: intellectual property rights; Jasper Therapeutics: Other: Intellectual property rights. Sevilla: Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Sevilla is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, and may be entitled to receive financial benefits from the licensing of such patents., Patents & Royalties: J. Sevilla is a consultant and has licensed medical products from Rocket Pharmaceuticals, Inc. ; Amgen: Consultancy; Novartis: Consultancy; Miltenyi: Consultancy; SOBI: Consultancy. Booth: GSK: Honoraria; Orchard Therapeutics: Consultancy, Honoraria; SOBI: Consultancy, Honoraria; Takeda: Honoraria; Rocket Pharmaceuticals, Inc.: Consultancy. Río: Rocket Pharmaceuticals: Current equity holder in publicly-traded company, Other: Paula Rio has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Research Funding. Navarro: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: Dr. Navarro has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Beard: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Wagner: Magenta Therapeutics: Consultancy; Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company; Vertex Pharmaceuticals: Consultancy; ASC Therapeutics: Consultancy; Bluebird Bio: Consultancy. Rao: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Thrasher: Orchard Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; 4Bio Capital: Consultancy, Membership on an entity's Board of Directors or advisory committees; Generation bio: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Rocket Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Schwartz: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren: Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Bueren is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, may be entitled to receive financial benefits from the licensing of such patents and receives funding for research., Patents & Royalties, Research Funding.