Definition

A bispecific T-cell engager (BiTE) antibody composed of two single-chain variable fragments (scFv), one directed against the tumor-associated antigen (TAA) CD33 fused to one that is directed against the CD3 antigen found on T lymphocytes, with potential immunostimulating and antineoplastic activities. Upon administration, emerfetamab binds to both the CD3 antigen on cytotoxic T lymphocytes (CTLs) and the CD33 antigen found on CD33-expressing tumor cells. This activates and redirects CTLs to CD33-expressing tumor cells, which results in the CTL-mediated cell death of CD33-expressing tumor cells. CD33, a myeloid differentiation antigen, is expressed on normal non-pluripotent hematopoietic stem cells and overexpressed on a variety of cancer cell types, including acute myeloid leukemia (AML). It plays a key role in tumor initiation, proliferation and progression.