Definition

A humanized bispecific antibody composed of a monovalent unit directed against the tumor-associated antigen (TAA) human epidermal growth factor 2 (HER2; ErbB2; HER-2) and a single chain unit directed against CD3 found on T lymphocytes, with potential immunostimulatory and antineoplastic activities. Upon administration, anti-HER2/anti-CD3 bispecific antibody M802 binds to both CD3 on cytotoxic T lymphocytes (CTLs) and HER2 on HER2-expressing tumor cells. This activates and redirects CTLs to HER2-expressing tumor cells, which results in the CTL-mediated cell death of HER2-expressing tumor cells. HER2 is overexpressed in a variety of cancer cell types and is associated with increased tumor cell proliferation.