Definition

A bispecific antibody and T-cell engager composed of two single chain variable fragments (bi-scFvs) directed against both a mutant form of the human epidermal growth factor receptor (EGFR), EGFR variant III (EGFRvIII), and the epsilon subunit of the human T-cell surface antigen CD3, with potential immunostimulating and antineoplastic activities. Upon administration, anti-EGFRvIII/CD3 bispecific antibody hEGFRvIII:CD3 bi-scFv specifically binds to both CD3 on cytotoxic T lymphocytes (CTLs) and hEGFRvIII on hEGFRvIII-expressing tumor cells. This crosslinks T cells and tumor cells, and activates and redirects CTLs to hEGFRvIII-expressing tumor cells. This leads to CTL-mediated killing of hEGFRvIII-expressing tumor cells. hEGFRvIII, a mutant form of EGFR expressed in certain tumor cell types and frequently seen in malignant glioma, plays a key role in tumor cell proliferation and survival.