Advancements in bispecific antibodies for multiple myeloma: What's new and what lies ahead

Recent advancements in multiple myeloma (MM) treatment—including immunomodulatory drugs, proteasome inhibitors, monoclonal antibodies, and T cell–redirecting therapies like chimeric antigen receptor (CAR) T cells and bispecific antibodies (BsAbs)—have significantly improved patient outcomes. However, MM remains incurable, highlighting the need for novel therapeutic strategies. BsAbs, which simultaneously target a tumor-specific antigen and CD3 on T cells, have shown promising efficacy. Three BsAbs - teclistamab, elranatamab, and talquetamab - have been approved for relapsed or refractory MM, demonstrating response rates of 60 %-74 % and median progression-free survival of approximately 1 year. This review provides a comprehensive overview of the latest advancements in BsAb therapy for MM, focusing on new therapeutic targets such as BCMA, GPRC5D, and FcRH5, recent clinical trial data, safety considerations, and future directions. We discuss tumor-intrinsic mechanisms of resistance, including antigen expression variability and antigen escape, as well as immune-related factors like T-cell exhaustion and an immunosuppressive microenvironment. Future strategies involve integrating BsAbs earlier in treatment, combining them with other agents to enhance efficacy and overcome resistance, and optimizing administration protocols to mitigate adverse effects. By examining these developments, we highlight how BsAbs are reshaping the treatment landscape of MM and underscore the importance of ongoing research to improve survival and quality of life for patients.