An antibody-drug conjugate (ADC) consisting of a monoclonal antibody against the tumor-associated antigen (TAA) B-cell maturation antigen (BCMA, TNFRSF17), linked to an as of yet undisclosed cytotoxic agent, with potential antineoplastic activity. Upon administration of anti-BCMA ADC CC-99712, the antibody moiety targets and binds to the cell surface antigen BCMA expressed on certain cancer cells. Upon binding and internalization, the cytotoxic agent is released and kills the BCMA-expressing cancer cells through an as of yet unknown mechanism of action. BCMA, a receptor for a proliferation-inducing ligand (APRIL; tumor necrosis factor ligand superfamily member 13; TNFSF13), and B-cell activating factor (BAFF), is a member of the tumor necrosis factor (TNF) receptor superfamily and plays a key role in plasma survival. It is found on the surfaces of plasma cells and is overexpressed on malignant plasma cells.