Comparison of Standard-of-Care Idecabtagene Vicleucel and Ciltacabtagene Autoleucel in Relapsed/Refractory Multiple Myeloma

PURPOSE: Idecabtagene vicleucel (ide-cel) and ciltacabtagene autoleucel (cilta-cel), two B-cell maturation antigen-directed chimeric antigen receptor (CAR) T-cell therapies have demonstrated remarkable efficacy in relapsed/refractory multiple myeloma (RRMM). We compare safety, efficacy, and survival among patients with RRMM treated with standard-of-care (SOC) ide-cel or cilta-cel. METHODS: Data were from a retrospective chart review of patients with RRMM leukapheresed by December 31, 2022, with the intent to receive SOC ide-cel or cilta-cel at 19 institutions. An inverse probability of treatment weighting (IPTW) approach was used to compare outcomes by therapy type. RESULTS: A total of 641 patients were leukapheresed by December 31, 2022, with ide-cel (n = 386) and cilta-cel (n = 255). Five hundred eighty-six patients were infused (n = 350 for ide-cel; n = 236 for cilta-cel) with a median follow-up of 12.6 and 13.0 months for ide-cel and cilta-cel, respectively. After IPTW, patient characteristics were well balanced. Cilta-cel was associated with higher likelihood of grade ≥3 cytokine release syndrome (CRS; odds ratio OR, 6.80 95% CI, 2.28 to 20.33), infections (OR, 2.03 95% CI, 1.41 to 2.92), second primary malignancies (OR, 1.77 95% CI, 0.89 to 3.56), and delayed neurotoxicity (OR, 20.07 95% CI, 4.46 to 90.20). Cilta-cel was also associated with better treatment responses (≥complete response: OR, 2.42 95% CI, 1.63 to 3.60), longer progression-free survival (hazard ratio HR, 0.48 95% CI, 0.36 to 0.63), and longer overall survival (HR, 0.67 95% CI, 0.46 to 0.97). No associations were observed between therapy type and immune effector cell-associated neurotoxicity syndrome, any CRS, severe cytopenia at days 30 and 90, or nonrelapse mortality. We observed consistent findings when repeating the analyses restricting the ide-cel cohort to patients infused during the same time period as Food and Drug Administration approval for cilta-cel (≥March 2022). CONCLUSION: Cilta-cel demonstrated superior efficacy and survival, with higher incidence of certain toxicities, compared with ide-cel.