Immune cell therapies targeting B-cell maturation antigen (BCMA) have been developed for relapsed and refractory multiple myeloma (RR-MM). Chimeric antigen receptor (CAR)-T cell therapies appear promising for RR-MM, and two BCMA-targeting CAR-T cell products, idecabtagene vicleucel and ciltacabtagene autoleucel, have achieved the highest response rates in heavily treated patients to date. These CAR-T products have been approved for RR-MM previously treated with 3 agents (proteasome inhibitors, immunomodulatory drugs, and anti-CD38 antibodies) in Japan. Despite the promising efficacy of CAR-T therapy, several issues remain to be resolved to establish its best use in routine clinical practice. In addition, most patients who receive CAR-T cell therapy eventually relapse after a long or short remission, and a better understanding of mechanisms of resistance and relapse following CAR T-cell therapy for MM will be necessary to overcome resistance to CAR-T therapy. In the near future, early initiation of CAR-T therapy for RR and development of next-generation CAR-T cell products should further improve prognosis in patients with MM.
Keywords: B-cell maturation antigen; Chimeric antigen receptor-T cell; Multiple myeloma.