Standard-of-care idecabtagene vicleucel for relapsed/refractory multiple myeloma

ABSTRACT: Idecabtagene vicleucel (ide-cel) was the first US Food and Drug Administration-approved chimeric antigen receptor T-cell (CAR-T) therapy for multiple myeloma (MM). However, because clinical trials are highly selective with stringent eligibility criteria, the objective of this study was to evaluate the safety and effectiveness of standard-of-care (SOC) ide-cel in the real world. Using the Center for International Blood and Marrow Transplant Research registry, we evaluated 821 patients who received SOC ide-cel. Median follow-up was 11.6 months. Median age was 66 years, and the cohort included 31% patients aged ≥70 years, with 15% Black and 7% Hispanic, and 77% of patients with ≥1 significant comorbidity. The median number of prior lines of therapy was 7, 15% patients previously received B-cell maturation antigen-directed therapy, 17% had extramedullary disease, and 27% had high-risk cytogenetics. Overall response rate was 73%, and complete response rate was 25%. Median progression-free survival was 8.8 months. Treatment-related mortality was reported in 6% of patients. Cytokine release syndrome was diagnosed in 80% of patients (grade ≥3, 3%). Immune effector cell-associated neurotoxicity syndrome was observed in 28% (grade ≥3, 5%), with no cases of Parkinsonism reported. Clinically significant infections were seen in 45% of patients. Second primary malignancies were reported in 4%, including 1% myeloid malignancies. This is, to our knowledge, the largest real-world study of ide-cel CAR-T therapy in patients with relapsed/refractory (R/R) MM. We observed a favorable safety and efficacy profile that mirrors trial experience, even in the setting of significant comorbidities in 77% of patients, many of which would have made them ineligible for the registrational KarMMa clinical trial. This trial was registered at www.clinicaltrials.gov as #NCT03361748.