B-cell Maturation Antigen (BCMA) –targeted Immunotherapies. A) Antibody-drug conjugate (ADC): Upon binding to BCMA on the surface of multiple myeloma (MM) cells, ADC is internalized first and the linker is hydrolyzed inside of the lysosomes or endosomes, releasing the payloads that lead to cell death. B) Chimeric antigen receptor cells (CAR-Ts): The ectodomain of the BCMA scFv on the CAR-Ts binds to BCMA on the surface of MM cells. This leads to activation of the CAR-Ts, which release cytotoxic cytokines and cause MM cell death. C) Bispecific T-cell engager (BiTE). The dual BCMA- and CD3-scFv–containing BiTE binds concomitantly to CD3 and BCMA, facilitating T cell/MM cell crosslinking, followed by CD4+/CD8+ T-cell activation and secretion of cytotoxic cytokines, leading to MM cell death.