Definition

A bispecific antibody directed against two distinct domains of the tumor-associated antigen (TAA) human tyrosine kinase receptor epidermal growth factor receptor 2 (HER2; ErbB2; HER-2), with potential immunomodulating and antineoplastic activities. Upon administration, anti-HER2 bispecific antibody KM257 simultaneously targets and binds to two different domains of HER2. This prevents the activation of HER2 signaling pathways. In addition, by binding to HER2, KM257 induces an antibody-dependent cell-mediated cytotoxicity (ADCC) against tumor cells that express HER2. This results in tumor cell apoptosis and inhibits the proliferation of HER2-expressing tumor cells. HER2, overexpressed on a variety of tumor cell types, plays an important role in tumor cell proliferation, differentiation and survival.