[Mechanism of action and clinical results of immunotherapy for multiple myeloma].

Treatment outcomes for multiple myeloma (MM) have improved due to the introduction of autologous stem cell transplantation and novel drugs. However, many patients develop resistance to existing therapies; hence, novel treatment strategies for these patients must be established. Therapeutic antibodies, including daratumumab and isatuximab targeting CD38 and elotuzumab targeting SLAMF7, have been introduced as immunotherapies for MM. These antibodies exert cytotoxic effects on myeloma cells through the activation of effectors such as natural killer cells and complement, and induction of phagocytosis by macrophages. Suppressed anti-tumor immunity may be related to acquisition of drug resistance by myeloma cells in patients with MM. It has been reported that the effect of therapeutic antibodies is through the stimulation of anti-tumor immunity. Thus, as each therapeutic antibody displays its own mechanism of action, therapy based on this mechanism of action should be introduced. Furthermore, chimeric antigen receptor (CAR) T-cell therapy, antibody drug conjugates (ADC), and bispecific antibodies (BsAbs) are gradually being introduced as novel immunotherapies for MM. CAR T-cells with high proliferation levels and persistence in recipients to improve the duration of therapeutic response are currently being developed.