Definition

A tetravalent, bispecific antibody directed against both the tumor-associated antigen (TAA) human B-cell maturation antigen (BCMA; tumor necrosis factor receptor superfamily member 17; TNFRSF17) and the T-cell surface antigen CD3, with potential immunostimulating and antineoplastic activities. Upon administration, anti-BCMA/anti-CD3 bispecific antibody EMB-06 binds to both CD3 on cytotoxic T lymphocytes (CTLs) and BCMA on BCMA-expressing tumor cells. This activates and redirects CTLs to BCMA-expressing tumor cells, leading to CTL-mediated killing of BCMA-expressing tumor cells. BCMA, a receptor for a proliferation-inducing ligand (APRIL) and B-cell activating factor (BAFF), is a member of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF) and plays a key role in plasma cell survival; it is found on the surfaces of plasma cells and overexpressed on malignant plasma cells. In EMB-06, the two antigen-binding fragments (Fabs) are fused directly in a crisscross orientation resulting in four active and independent antigen binding sites.