Results from Lummicar-2: A Phase 1b/2 Study of Fully Human B-Cell Maturation Antigen-Specific CAR T Cells (CT053) in Patients with Relapsed and/or Refractory Multiple Myeloma

Abstract

CT053 comprises autologous T cells genetically modified with a second-generation chimeric antigen receptor (CAR) incorporating a fully human B-cell maturation antigen (BCMA)-specific single-chain fragment variant (25C2) with high binding affinity. Twenty-four subjects have been treated in phase 1 studies with an 87.5% overall response rate (ORR), 79.2% complete response (CR), and a median duration of response of 21.8 months without inducing immunogenicity [Blood (2019) 134 (Supplement_1): 4435]. Here we present the ongoing phase 1b/2 study (LUMMICAR-2) conducted in North America (NCT03915184) to evaluate safety and clinical efficacy. Eligible subjects with relapsed/refractory multiple myeloma (RRMM) had received ≥3 prior lines of therapy including a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and an anti-CD38 antibody, and had measurable disease per International Myeloma Working Group (IMWG) criteria. All subjects received a lymphodepletion regimen of cyclophosphamide (500 mg/m2/day ×2 days) and fludarabine (25 mg/m2/ day × 3 days). A single infusion of CT053 at the targeted 1.5-3.0×108 CAR+ T-cell dose was administered after lymphodepletion. Primary objectives for phase 1b were to evaluate the safety and tolerability of CT053 and to identify the recommended phase 2 dose. Adverse events (AEs) were graded using CTCAE, v5.0; cytokine release syndrome (CRS) and neurotoxicity were graded according to ASTCT CRS consensus grading system (Lee DW et al, 2019). The response was assessed per 2016 IMWG criteria, and minimal residual disease (MRD) was assessed by next generation flow cytometry or sequencing. As of July 28, 2020, 20 subjects have enrolled, and 14 subjects have received CT053 infusion in the phase 1b portion of the study, including 8 subjects who received 1.5-1.8×108 CAR+ T cells while 6 subjects received 2.5-3.0×108 CAR+ T cells. The treated subjects had a median age of 59 years (range 42-73), had received a median of 6 (range 3-11) prior lines of treatment, 93% were triple refractory to a PI, IMiD, and anti-CD38 antibody, and 64% were penta-refractory. In addition, 36% of the subjects had extramedullary disease at baseline, and 64% had high-risk cytogenetics. All subjects received bridging therapy. The most common ≥ grade 3 AE was hematological toxicity. All subjects experienced ≥ grade 3 neutropenia (100%) and leukopenia (100%), and 36% of subjects had ≥ grade 3 thrombocytopenia within 30 days of treatment. No grade 3 or higher CRS or neurotoxicity was observed. Twelve of 14 subjects (86%) experienced grade 1 or 2 CRS, including 2 subjects who experienced grade 2 CRS and 1 subject who had grade 2 neurotoxicity. CRS events had a generally predictable time to onset, occurring at a median of 2 days post infusion with a median duration of 4 days (range 1-6). Two subjects received tocilizumab, and one subject with grade 2 CRS received both tocilizumab and steroids. One subject experienced grade 2 neurotoxicity with complete resolution within 24 hours upon administration of dexamethasone. At the data cutoff, 10 subjects were evaluable for at least two months of efficacy assessment with a median follow-up of 4.5 months (range 2-8). A 100% ORR was observed, with 2 stringent complete responses, 2 CRs, 1 very good partial response, and 5 partial responses. Of the 12 subjects with evaluable bone marrow samples, 11 were MRD-negative at the 10-5 sensitivity level. Responses were independent of baseline bone marrow BCMA expression. CT053 transgene levels showed expansion and persistence in peripheral blood, with peak expansion at 7-14 days after infusion. All subjects showed similar kinetics of rapid declines in serum free light chains and soluble BCMA (sBCMA) levels within 1 month, and continued depletion in sBCMA suggests CT053-mediated pharmacodynamic activity. Serum C-reactive protein and cytokine levels (i.e., IL-6, IFNγ, IL-8, IL-10) increased post-infusion within 7 days and correlated with the onset of CRS symptoms. Collectively, these results demonstrate that CT053 at a target dose of 1.5-3.0×108 CAR+ T cells delivers early and deep responses, including MRD negativity, with an acceptable safety profile in subjects with heavily pretreated relapsed or refractory MM. The promising results from the ongoing LUMMICAR-2 study are consistent with the previous phase 1 studies and support the launch of a pivotal Phase 2 LUMMICAR-2 study. Updated results will be presented at the conference. Disclosures Kumar: Carsgen: Other, Research Funding; Kite Pharma: Consultancy, Research Funding; Oncopeptides: Consultancy, Other: Independent Review Committee; IRC member; Celgene/BMS: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Genentech/Roche: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Adaptive Biotechnologies: Consultancy; Janssen Oncology: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Dr. Reddy's Laboratories: Honoraria; Tenebio: Other, Research Funding; Genecentrix: Consultancy; BMS: Consultancy, Research Funding; AbbVie: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Amgen: Consultancy, Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments, Research Funding; MedImmune: Research Funding; Cellectar: Other; Merck: Consultancy, Research Funding; Takeda: Other: Research funding for clinical trials to the institution, Consulting/Advisory Board participation with no personal payments; Sanofi: Research Funding; Novartis: Research Funding; Karyopharm: Consultancy. Baz:Sanofi, Karypharm, Janssen, Celgene: Other: Advisory board; Karyopharm, janssen, Bristol Myers Squibb, Celgene, Merck, Sanofi, Abbvie Inc.: Research Funding. Orlowski:Amgen, Inc., AstraZeneca, BMS, Celgene, EcoR1 Capital LLC, Forma Therapeutics, Genzyme, GSK Biologicals, Ionis Pharmaceuticals, Inc., Janssen Biotech, Juno Therapeutics, Kite Pharma, Legend Biotech USA, Molecular Partners, Regeneron Pharmaceuticals, Inc.,: Honoraria, Membership on an entity's Board of Directors or advisory committees; Founder of Asylia Therapeutics, Inc., with associated patents and an equity interest, though this technology does not bear on the current submission.: Current equity holder in private company, Patents & Royalties; STATinMED Research: Consultancy; Sanofi-Aventis, Servier, Takeda Pharmaceuticals North America, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Laboratory research funding from BioTheryX, and clinical research funding from CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Research Funding. Anderson:Amgen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Ma:CARsgen Therapeutics Corp.: Current Employment. Bilgi:CARsgen Therapeutics Corp.: Other: Current shareholder in the company. Kansagra:Alnylam Pharmaceuticals, Bristol Myers Squibb /Celgene, GlaxoSmithKline, Janssen, Pharmacyclics, Takeda Pharmaceuticals, Pfizer, Karyopharm Therpeutics: Other: Advisory Board. Kapoor:Janssen: Research Funding; Cellectar: Consultancy; Takeda: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; Celgene: Honoraria; Amgen: Research Funding; Sanofi: Consultancy, Research Funding. Li:CARsgen Therapeutics Co. LtD: Current Employment, Current equity holder in private company. Brayer:Bristol-Myers Squibb, WindMIL Therapeutics: Research Funding; Janssen: Consultancy; Bristol-Myers Squibb, Janssen, Amgen: Speakers Bureau.

Novel Experimental Drugs for Treatment of Multiple Myeloma

“…This product, manufactured in nearly 8–10 days, was at first assessed in a phase I study in China 86 and after a follow-up of 24 months, among 24 patients enrolled in one year, ORR was 87% including 79% with CR/sCR and median PFS 18.8 months. In the USA, the phase I trial Ib/II Lummicar-2 study, 87 using CT053, has enrolled 20 patients to date. Preliminary data presented at the last ASH meeting showed the achievement of ORR in 94% of patients with 11/12 evaluable patients obtaining MRD negativity at level of 10 −5 .…”

Rapid Progress in Immunotherapies for Multiple Myeloma: An Updated Comprehensive Review

“…CRB-402, bb21217, a phase 1 dose escalation trial of bb21217 in 46 RRMM patients was conducted, and BCMA+ CAR-T cells across a dose range of 150–450 × 10 6 /kg were given [ 149 ]. The updated results included a 55% ORR with 18% CR, and 30% VGPR.…”

“…In contrast, CRS with a grade > 3 occurred only in 4% of patients. Twenty-two percent of patients experienced neurotoxicity, including 6% of grade > 3 events with a median time to onset of seven days [ 149 ] ( Table 5 ).…”

CART-Cell Therapy: Recent Advances and New Evidence in Multiple Myeloma

“…Twenty-four subjects have been treated in phase 1 studies with an 87.5% ORR, 79.2% CR, and a median duration of response of 21.8 months without inducing immunogenicity [ 41 ]. Kumar et al presented the results of the ongoing phase 1b/2 study (LUMMICAR-2) conducted in North America (NCT03915184) to evaluate the safety and clinical efficacy [ 42 ]. At the data cutoff, ten subjects were evaluable for at least two months of efficacy assessment with a median follow-up of 4.5 months (range 2–8).…”