B-cell maturation antigen (BCMA) in multiple myeloma: the new frontier of targeted therapies

Outcomes of patients with multiple myeloma (MM) who become refractory to standard therapies are particularly poor and novel agents are greatly needed to improve outcomes in such patients. B-cell maturation antigen (BCMA) has become an important therapeutic target in MM with three modalities of treatment in development including antibody-drug conjugates (ADCs), bispecific T-cell engagers (BITEs), and chimeric antigen receptor (CAR) T-cell therapies. Early clinical trials of anti-BCMA immunotherapeutics have demonstrated extremely promising results in heavily pretreated patients with relapsed/refractory MM (RRMM). Recently, belantamab mafodotin was the first anti-BCMA therapy to obtain approval in relapsed/refractory MM. This review summarizes the most updated efficacy and safety data from clinical studies of BCMA-targeted therapies with a focus on ADCs and BITEs. Additionally, important differences among the BCMA-targeted treatment modalities and their clinical implications are discussed.