Cilta-Cel Efficacy and Safety in Patients with Progressive Multiple Myeloma after Exposure to Non-Cellular Anti-BCMA Immunotherapy

ABSTRACT

Introduction: CARTITUDE-2 (NCT04133636) is a phase 2, multicohort study evaluating cilta-cel, an anti-BCMA CAR-T therapy, in several multiple myeloma (MM) patient (pt) populations. Objective(s) To report updated results with longer follow-up on cohort C pts with previous exposure to a non-cellular anti- BCMA immunotherapy. Method(s) Cohort C pts had progressive MM after treatment (tx) with a proteasome inhibitor, immunomodulatory drug, anti-CD38 antibody, and non-cellular BCMA-targeting agent. A single cilta-cel infusion (target dose 0.75x106 CAR+ viable T cells/kg) was administered 5-7 days post lymphodepletion. Primary endpoint was minimal residual disease (MRD) negativity at 10-5. Secondary endpoints included overall response rate (ORR), duration of response (DOR), and adverse events (AEs). Result(s) As of June 1, 2022, 20 pts (13 ADC exposed;7 BsAb exposed) were treated with cilta-cel;4 pts did not receive cilta-cel due to either low cellular yield (n=2, 1 in each group) or death due to progressive disease (PD) prior to dosing (n=2, 1 in each group) and 6 pts received anti-BCMA tx as their last line of therapy (n=4 ADC, n=2 BsAb). During prior anti-BCMA tx, best responses included VGPR (ADC 2 pts;BsAb 1 pt), sCR (ADC 1 pt), and CR (BsAb 1 pt);the rest had best response of stable disease or PD (1 pt not evaluable). Baseline characteristics are presented in Figure 1A. Median time from last anti- BCMA agent to cilta-cel infusion was 195 d;median administered dose of cilta-cel was 0.65x106 CAR+ viable T cells/kg. At a median follow-up of 18.0 mo, 7/10 evaluable pts (70%) were MRD negative at 10-5 (ADC 5/7 [71.4%], BsAb 2/3 [66.7%]). ORR full cohort, 60%;ADC, 61.5%;BsAb, 57.1% (Figure 1B). Median DOR full cohort, 12.8 mo;ADC, 12.8 mo;BsAb, 8.2 mo. Median PFS full cohort, 9.1 mo;ADC, 9.5 mo;BsAb, 5.3 mo. Cilta-cel responders had a shorter median duration of last anti- BCMA agent exposure (29.5 d) compared with non-responders (63.5 d). Responders also had a longer median time from last anti-BCMA tx exposure to apheresis (161.0 d) than non-responders (56.5 d). Most common AEs were hematologic. CRS n=12 (60%;all Gr1/2), median time to onset 7.5 d, median duration 6.0 d. ICANS n=4 (20%, 2 Gr3/4), median time to onset 9.0 d, median duration 7.0 d. No patient had movement or neurocognitive tx emergent AE/parkinsonism. There were 12 deaths (PD 8;COVID-19 pneumonia 2 [not tx related];subarachnoid hemorrhage 1 [not tx related];C. difficile colitis 1 [tx related]). (Figure Presented)(Figure Presented)Conclusions: Pts with heavily pretreated MM and previous exposure to a non-cellular anti-BCMA therapy had favorable responses to cilta-cel. However, depth and DOR appear lower than that seen in anti-BCMA-naive pts treated with cilta-cel (at 27.7 mo, median DOR was not reached in heavily pre-treated but anti-BCMA naive CARTITUDE-1 pts). These data may inform tx plans, including sequencing and washout period between BCMA-targeting agentsCopyright © 2023 American Society for Transplantation and Cellular Therapy