Definition

A bispecific antibody and T-cell engager (TCE) targeting both the tumor-associated antigen (TAA) CD20 and the T-cell surface antigen CD3, with potential immunomodulating and antineoplastic activities. Upon administration, anti-CD20/anti-CD3 bispecific antibody MBS303 binds to both T cells and CD20-expressing B-lineage tumor cells. The resulting cross-linkage may trigger a potent cytotoxic T-lymphocyte (CTL) response against the CD20-expressing tumor B-cells. CD20 is exclusively expressed on B cells during most stages of B-cell development and is often overexpressed in B-cell malignancies. MBS303, composed of a 2:1 bispecific antibody structure, binds to CD20 with two arms and CD3 molecule with one arm to increase affinity with tumor cells and decrease the off-target toxicity of T cells.