Outcomes of Idecabtagene Vicleucel in relapsed/refractory Multiple Myeloma across Racial and Ethnic Groups: Real-World Evidence from the CIBMTR

Idecabtagene Vicleucel (ide-cel) is a standard therapy for relapsed/refractory multiple myeloma (RRMM), but real-world data on racial and ethnic disparities in outcomes remain limited. To evaluate racial and ethnic disparities in real-world response, survival, and toxicity outcomes following Idecabtagene Vicleucel therapy for relapsed/refractory multiple myeloma. A retrospective multicenter study was conducted on RRMM patients using the CIBMTR database between 2021 and 2023, based on the P6122 dataset. Outcomes assessed included overall response rate (ORR), complete response (CR), relapse, treatment-related mortality (TRM), overall survival (OS), progression-free survival (PFS), cytopenias, infection, cytokine release syndrome (CRS), and immune effector cell-associated neurotoxicity syndrome (ICANS). Chi-square tests, independent samples t-test, Kaplan–Meier analysis and Cox regression analyses were conducted. Analyses were done using SPSS, with a p-value < 0.05 statistically significant. A total of 813 patients were included in the study. The cohort comprised 610 non-Hispanic White patients, 117 non-Hispanic Black patients, 55 Hispanic patients, and 31 patients of other racial backgrounds. The ORR was 75.2% in White patients, 70.9% in Black patients, 49.1% in Hispanic patients, and 58.1% in others (p < 0.001). CR rates were highest in White patients (26.6%), followed by Black (23.9%), Hispanic (14.5%), and other patients (12.9%) (p < 0.001). Relapse occurred in 45.4% of White patients, 41.0% of Black patients, 49.1% of Hispanic patients, and 48.4% of other patients (p = 0.011). Median OS was comparable across racial groups (p = 0.772), with a median of 15.6 months in White patients, 17.5 months in Hispanic patients, and 13.1 months in other patients; the median OS was not reached for Black patients. Median PFS was also similar across groups (p = 0.842), with values of 8.9 months for White patients, 11.4 for Black patients, 8.5 for Hispanic patients, and 8.0 for others. Multivariable Cox regression analysis reported an insignificant association between race and OS and PFS. TRM was more common in White patients (4.8%) compared to Black (3.4%), Hispanic (1.8%), and other patients (3.2%, p = 0.011). Neutropenia was most frequent in Black patients (22.2%) compared to White (10.0%), Hispanic (5.5%), and other patients (3.2%) (p = 0.001). Thrombocytopenia was reported in 23.8% of White patients, 29.1% of Black patients, 18.2% of Hispanic patients, and 22.6% of others (p = 0.011). Infection rate, CRS and ICANS were comparable across all races. Certain disparities exist across different racial groups receiving CAR-T therapy, which might reflect small numbers of minority groups included in the patients receiving CAR-T or could reflect genetic/disease characteristics differences, and warrant further investigations.