Racial and ethnic differences in clinical outcomes among multiple myeloma patients treated with CAR T-cell therapy.

Idecabtagene vicleucel (ide-cel) was the first chimeric antigen receptor T-cell therapy to gain FDA approval for patients with relapsed/refractory multiple myeloma (RRMM). The clinical outcomes of standard of care (SOC) ide-cel in racially and ethnically diverse populations have been understudied. This study pooled data from 207 RRMM patients (28% racial and ethnic minority patients) treated with SOC ide-cel across 11 institutions to examine racial and ethnic differences in the incidence of toxicities and adverse events, response to ide-cel, and survival. This study included 22 (11%) Hispanic, 36 (17%) Non-Hispanic Black, and 149 (72%) Non-Hispanic White RRMM patients. Compared to Hispanic and Non-Hispanic White patients, Non-Hispanic Black patients had higher median levels of C-reactive protein (1.0, 0.8, and 3.5 mg/dL, respectively; P=0.02) and baseline ferritin (362.0 vs. 307.0 vs. 680.5, respectively; P=0.08) and were more likely to develop cytokine release syndrome (77%, 85%, and 97%, respectively; P=0.04). Although best overall response rate was lower among Hispanic patients (59%) compared to Non-Hispanic Black (86%) and White patients (86%; P=0.01), there were no racial and ethnic differences in progression-free or overall survival. We provide the first and largest investigation of clinical outcomes of SOC ide-cel by race and ethnicity. Despite differences in safety and response to ide-cel, our findings encourage the use of ide-cel in all RRMM patients. These findings should be confirmed in larger samples of diverse RRMM patients with longer follow-up time.