Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 2

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Assistance et interventions dans la recherche en matiere de prevision et prevention des risques naturels geologiques

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Response to Bcma CAR-T Cells Correlates with Pretreatment Target Antigen Density and Is Improved By Small Molecule Inhibition of Gamma Secretase

Introduction: The adoptive transfer of B-Cell Maturation Antigen (BCMA) chimeric antigen receptor (CAR) T cells is demonstrating early promise in multiple myeloma [MM], however durable responses remain elusive and most studies report >50% of patients relapsing within 18 months of receiving CAR-T cell therapy. The mechanism of relapse is likely the consequence of multiple factors including the variable distribution of BCMA on tumor cells, allowing cells with low antigen density to escape. Initial target density, receptor downregulation and the emergence of antigen loss variants have all been implicated in relapse following CAR-T cells directed against CD22 and CD19. Reduced or absent BCMA expression may similarly be linked to relapse in MM. We have previously demonstrated that BCMA cleavage by the γ-secretase complex reduces ligand density for CAR-T cell recognition, and that a small molecule γ-secretase inhibitor (GSI) markedly increases surface BCMA levels in a dose-dependent fashion while improving CAR-T cell recognition in preclinical models. Methods and Results: In a phase I first-in-human study (NCT03338972) employing a CAR-T cell construct encoding a fully human BCMA scFv and 4-1BB/CD3z, rapid and deep objective responses at CAR-T cell doses starting at 5 x 107 have been observed. All patients had bone marrow (BM) involvement at baseline (mean 42.5 % CD138+ by IHC) and 14/15 had no detectable disease in the BM 28 days after therapy. One patient with comparatively very low BCMA expression (BCMA antibody binding capacity [ABC; QuantiBRITE] = 269; 16.9% of the malignant plasma cells (PCs) BCMA+ by flow cytometry) was the only subject with persistent tumor cells in the BM 28 days after therapy. Despite complete BM responses in all remaining patients, late relapses have occurred. Differences in the BCMA expression level on tumor cells prior to CAR-T cells between long term responders and those with relapse are evident. Among the 12 subjects with at least 3 months of follow up, those remaining in remission (median 12 months, range 3-16; data cut off 7/15/19) demonstrated a median pre-treatment BCMA ABC of 1761 (range 781-2922, n=5), in contrast patients with relapse (mean of 7.3 months, range 2-12) had a median pre-treatment BCMA ABC of 920 (range 260-1540, n=7). Six patients with a pretreatment mean ABC of 919 (range 260-1540) had BM evaluable for BCMA expression at relapse and the mean ABC decreased to 304 (range 121-519). The percent PCs expressing BCMA decreased from 77.5% (range 13 - 99.8) to 30% (range 10.4-60.4). The impact of gamma secretase inhibition on BCMA expression was assessed on BM cells obtained from a patient relapsing after BCMA CAR-T cells. At relapse a 9.5-fold decrease in ABC from baseline was observed. The cells were cultured for 5 hours in the presence of GSI (JSMD194) at a concentration of 1mM, which is readily achievable by oral administration. A significant increase in BCMA antigen expression was observed (ABC=917). The impact of modulating BCMA expression on tumor cells by concurrently administering an oral GSI with CAR-T cells is being explored in a phase one clinical trial (NCT03502577). In this setting, the GSI has increased BCMA expression when low level residual BCMA was observed following relapse after prior BCMA therapy failure. Two patients have been evaluated for response to an JSMD194 after failing other BCMA targeted agents. One received a prior BCMA CAR-T cell product and after relapse demonstrated a BCMA ABC of 769. Target expression increased in this patient almost nine-fold to 6828 (ABC) after three oral doses of JSMD194. A second patient had a BCMA ABC of 666 after failing a BCMA bispecific T cell engager. BCMA density increased over 14-fold to 9583 after GSI. Comprehensive data from the combination GSI and BCMA CAR-T cell trial are being reported separately. Conclusion: Pretreatment BCMA target density quantified with a uniform flow cytometry method of measurement and performed on all patients enrolled on a single center BCMA CAR-T cell clinical trial is associated with the durability of response. Further, BCMA expression can be significantly increased following GSI exposure in patients evidencing low BCMA ABC at baseline or when downregulation is the consequence of prior BCMA targeting therapy. The capacity for GSIs to increase BCMA target density and decrease soluble BCMA levels is a promising approach to be exploited in clinical trials. Disclosures Green: Juno Therapeutics: Consultancy, Patents & Royalties, Research Funding; Celgene: Consultancy; GSK: Consultancy; Seattle Genetics: Research Funding; Cellectar: Research Funding. Pont: Fred Hutchinson Cancer Research Center: Other: Inventor on a patent. Cowan: Sanofi: Consultancy; Juno: Research Funding; Abbvie: Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Cellectar: Consultancy. Sather: Lyell Immunopharma: Employment, Equity Ownership. Blake: Celgene: Employment, Equity Ownership. Works: Celgene: Employment, Equity Ownership. Maloney: Juno Therapeutics: Honoraria, Patents & Royalties: patients pending , Research Funding; A2 Biotherapeutics: Honoraria, Other: Stock options ; BioLine RX, Gilead,Genentech,Novartis: Honoraria; Celgene,Kite Pharma: Honoraria, Research Funding. Riddell: Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy; Lyell Immunopharma: Equity Ownership, Patents & Royalties, Research Funding. OffLabel Disclosure: Oral Gamma Secretase Inhibitor. Purpose is to increase expression of B Cell Maturation Antige

Fully Human Bcma Targeted Chimeric Antigen Receptor T Cells Administered in a Defined Composition Demonstrate Potency at Low Doses in Advanced Stage High Risk Multiple Myeloma

Abstract Background: Despite advances in the treatment of multiple myeloma (MM) almost all patients relapse and high risk features continue to portend a short median survival. The adoptive transfer of B-Cell Maturation Antigen (BCMA) chimeric antigen receptor (CAR) T cells is demonstrating early promise in MM, but the durability of response has not been established. The infusion of genetically modified CD8+ and CD4+ T cells of a defined composition facilitates the evaluation of each subset's function and has contributed to reproducible efficacy and safety in clinical trials with CD19-specific CAR T cells. In this phase I first-in-human study employing a human scFv containing BCMA CAR T cell construct, we report rapid and deep objective responses at a low CAR T cell dose level (5 x 107) suggesting that construct specific features and differences in product formulation may substantially impact efficacy. Methods: Eligible patients had relapsed or treatment refractory MM, ≥10% CD138+ bone marrow (BM) plasma cells (PC), and ≥5% BCMA expression by flow cytometry (FC). Patients were stratified by tumor burden (CD138+ IHC) into two cohorts; 10-30% MM cells [cohort A] or >30% BM involvement [cohort B] to facilitate assessment of impact of disease burden on outcome. Eligible patient's CD8+ and CD4+ T cells were isolated via positive selection, enriched separately by immunomagnetic selection and cryopreserved. The CD8+ and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads and transduced with a 3rd generation lentiviral vector encoding a fully human BCMA scFv and 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ BCMA CAR T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) was encoded in the transgene cassette to identify transduced T cells. Lymphodepleting chemotherapy preceded infusion of EGFRt+ CAR T cells at a starting dose of 5 x 107 EGFRt+ cells (n=5) for each cohort. Results: Seven patients (median age of 63 years; range 49 to 76) with a median of 8 prior regimens (range 6 to 11) have received treatment. The median %PC in BM (IHC) at enrollment was 58% (range 20% to >80%). In cohort B the dose has been escalated to 15 x107 EGFRt+ cells (n=2). All patients (7/7) had at least one high risk cytogenetic feature (17p- [n=4], t(4;14) [n=2], t(14;16) [n=1]), 71% had ≥ 2 high risk cytogenetic features, 71% had prior autologous stem cell transplant, 43% had prior allogeneic transplant, and one patient (14%) had PCL. The median involved free light chain (FLC) at enrollment was 180 mg/dL (range 40.37 to 502.96 mg/dL; n=5) and the median monoclonal protein was 3.8 g/dL (range 1.6 to 6.5 g/dL; n=5). The overall response rate at 28 days was 100%; at this time all evaluable patients (n=6) had no detectable abnormal BM PC clone by both IHC and high sensitivity FC. Within 28 days of treatment the involved FLC was normal or sub-normal in all patients and the M-protein had decreased by a median of 73% (range 56.25 to 83% reduction). BCMA CAR T cells remained detectable 90 days after infusion, representing up to 41.5 percent of CD3+ lymphocytes. All patients were surviving at a median of 16 wks (range 2 to 26 wks). One patient relapsed (day +60) and a tumor biopsy demonstrated the presence of a BCMAneg PC population, a 70% reduction in the fraction of MM cells expressing BCMA by FC and a fivefold reduction in BCMA antigen binding capacity on MM cells retaining target expression. A cytotoxic T lymphocyte response to the trans-gene product was not identified in this patient. No dose limiting toxicity has been observed during the 28 day monitoring window and treatment has been well tolerated with no cytokine release syndrome (CRS) observed in one patient and grade 2 or lower CRS (Lee Criteria) for all other patients. No neurological toxicity has been observed. Conclusion: BCMA CAR T cells harboring a fully human scFv with a defined composition of CD4+:CD8+ T cells were well tolerated and potent, demonstrating complete objective responses in heavily pretreated high-risk MM at total cell doses as low as 5 x 107. Next generation sequencing and multiparameter high sensitivity flow cytometry studies to evaluate for minimal residual disease are ongoing. Peak expansion levels and persistence of the CAR T cells are being monitored with early findings suggesting an absence of transgene product immunogenicity. Disclosures Green: Juno Therapeutics: Patents & Royalties, Research Funding. Sather:Juno Therapeutics: Employment. Cowan:Janssen: Research Funding; Abbvie: Research Funding; Juno Therapeutics: Research Funding; Sanofi: Research Funding. Turtle:Caribou Biosciences: Consultancy; Gilead: Consultancy; Bluebird Bio: Consultancy; Precision Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Aptevo: Consultancy; Eureka Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Nektar Therapeutics: Consultancy, Research Funding; Juno Therapeutics / Celgene: Consultancy, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy. Till:Mustang Bio: Patents & Royalties, Research Funding. Becker:GlycoMimetics: Research Funding. Blake:Celgene: Employment, Equity Ownership. Works:Juno Therapeutics: Employment. Maloney:GlaxoSmithKline: Research Funding; Juno Therapeutics: Research Funding; Seattle Genetics: Honoraria; Roche/Genentech: Honoraria; Janssen Scientific Affairs: Honoraria. Riddell:Cell Medica: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy; NOHLA: Consultancy

Efficacy and Safety of Fully Human Bcma CAR T Cells in Combination with a Gamma Secretase Inhibitor to Increase Bcma Surface Expression in Patients with Relapsed or Refractory Multiple Myeloma

Background: Although the median survival for patients with multiple myeloma has improved dramatically, almost all patients will eventually relapse and become resistant to standard therapies. Chimeric antigen receptor T cells (CAR T cells) targeting B cell maturation antigen (BCMA) have shown early promise in MM, with high initial response rates. Responses are often incomplete and durability has been a key concern, with most patients relapsing within 1 year (Raje N et al NEJM 2019). We have previously demonstrated that gamma secretase inhibitors (GSI) increase BCMA surface density, decrease soluble BCMA levels and augment anti-tumor efficacy of BCMA CAR T cells in preclinical models. In a phase I first-in-human trial (NCT03502577), we combined CAR T cells expressing a fully human BCMA scFv with an orally administered gamma secretase inhibitor (JSMD194). Methods: Eligible patients had relapsed/refractory MM, with ≥ 10% plasma cells in the bone marrow by CD138 IHC, and measurable disease by IMWG criteria. BCMA was measured on CD138+ plasma cells by flow cytometry. CD8+ and CD4+ T cells were isolated via positive selection. The T cells were stimulated in separate cultures and transduced with lentiviral vector encoding a fully human BCMA scFv in conjunction with 41BB and CD3 zeta signaling domains. Following expansion, the cell product was formulated in a 1:1 ratio of CD4+:CD8+ BCMA CAR T cells. To assess the discreet impact of the GSI on plasma cell BCMA expression, patients received a GSI (JSMD194) monotherapy "run-in" involving three oral doses (25 mg) administered 48 hours apart over 5 days. A bone marrow aspirate was obtained on day 5 and BCMA expression on tumor cells was compared to baseline. Then, after lymphodepleting chemotherapy, BCMA CAR T cells were infused at a total starting dose of 5 x 10^7 EGFRt+ cells, in combination with JSMD194 dosed at 25 mg thrice weekly for three weeks, starting on the day of CAR infusion. Results: Eight patients, with a median age of 64.5 (range, 50-70 years) and a median of 10 prior regimens (range, 4-23), were screened, and seven patients have been treated. One patient had not responded to prior treatment with BCMA CAR T cells using a different construct, and another had progressed on a clinical trial employing a BCMA bispecific antibody. Median bone marrow plasma cell involvement by IHC was 32.5% (range, 10-80%) at enrollment. High-risk features were present in 75% of patients. Median involved serum free light chain at screening was 68.7 mg/dL (range18.45 - 365.61 mg/dL) and median monoclonal protein was 2.55 g/dL (range 0.1 - 5.1 g/dL). Following 3 oral doses (run in) of JSMD194, the percent of plasma cells expressing BCMA increased from 75% to 99% (7.6 to 98% pre, 75 to 100% post), soluble BCMA decreased by 2.0 fold (range 1.6 to 2.6 fold) after 3 oral doses, and BCMA antigen binding capacity increased from a median of 718 receptors to 13355 receptors per cell, or a median of 20-fold (range, 7.55-fold to 156.68-fold). Among 6 assessable patients, the best overall response rate was 100% (5 VGPR, 1 PR), with 5/6 patients MRD negative by flow. At data cutoff of July 15, 2019, no patient has relapsed, with a median follow-up of 5 months (range 1-11 months). One patient died at day 33 post-CAR T cell in the setting of cytokine release syndrome and concurrent fungal infection. The most common non-hematologic ≥ Grade 3 AE was neutropenic fever in 70%. CRS occurred in 100% of patients, primarily grades 1-2 (Lee Criteria), and neurotoxicity in 70%. Conclusions: Although BCMA CAR T cell therapy has demonstrated potent anti-tumor efficacy in multiple myeloma, a significant proportion of patients relapse. The mechanism of myeloma recrudescence requires further study, however BCMA antigen loss has been observed after CAR T cell therapy and is a putative pathway for tumor escape. In this study we demonstrate that gamma secretase inhibition with JSMD194 routinely increases BCMA surface density on myeloma cells in treated patients and reduces soluble BCMA. The combination of a gamma secretase inhibitor with BCMA CAR T cells leads to rapid responses including in patients that have failed prior BCMA targeted therapy. These responses are achieved with low CAR T cell doses. Longer follow up is required to determine if the durability of response is improved. Disclosures Cowan: Cellectar: Consultancy; Juno: Research Funding; Sanofi: Consultancy; Janssen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Abbvie: Research Funding. Pont:Fred Hutchinson Cancer Research Center: Other: Inventor on a patent. Sather:Lyell Immunopharma: Employment. Turtle:T-CURX: Membership on an entity's Board of Directors or advisory committees; Allogene: Other: Ad hoc advisory board member; Precision Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Humanigen: Other: Ad hoc advisory board member; Juno Therapeutics: Patents & Royalties: Co-inventor with staff from Juno Therapeutics; pending, Research Funding; Nektar Therapeutics: Other: Ad hoc advisory board member, Research Funding; Eureka Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Caribou Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Kite/Gilead: Other: Ad hoc advisory board member; Novartis: Other: Ad hoc advisory board member. Till:Mustang Bio: Patents & Royalties, Research Funding. Libby:Alnylam: Consultancy; Abbvie: Consultancy; Pharmacyclics and Janssen: Consultancy; Akcea: Consultancy. Becker:AbbVie, Amgen, Bristol-Myers Squibb, Glycomimetics, Invivoscribe, JW Pharmaceuticals, Novartis, Trovagene: Research Funding; Accordant Health Services/Caremark: Consultancy; The France Foundation: Honoraria. Blake:Celgene: Employment, Equity Ownership. Works:Celgene: Employment, Equity Ownership. Maloney:Juno Therapeutics: Honoraria, Patents & Royalties: patients pending , Research Funding; Celgene,Kite Pharma: Honoraria, Research Funding; BioLine RX, Gilead,Genentech,Novartis: Honoraria; A2 Biotherapeutics: Honoraria, Other: Stock options . Riddell:Juno Therapeutics: Equity Ownership, Patents & Royalties, Research Funding; Adaptive Biotechnologies: Consultancy; Lyell Immunopharma: Equity Ownership, Patents & Royalties, Research Funding. Green:Juno Therapeutics: Consultancy, Patents & Royalties, Research Funding; GSK: Consultancy; Celgene: Consultancy; Seattle Genetics: Research Funding; Cellectar: Research Funding. OffLabel Disclosure: Gamma secretase inhibitor to increase BCMA expression in multiple myelom