A recombinant, proprietary bispecific T-cell engagers (BiTE) antibody directed against human carcinoembryonic antigen (CEA), with potential immunostimulating and antineoplastic activities. Anti-CEA BiTE monoclonal antibody MEDI-565 possesses two antigen-recognition sites, one for CEA and one for the CD3 complex, a group of T cell surface glycoproteins that complex with the T cell receptor (TCR). This bispecific monoclonal antibody brings CEA-expressing tumor cells and cytotoxic T lymphocytes (CTLs) and helper T lymphocytes (HTLs) together, which may result in the CTL- and HTL-mediated cell death of CEA-expressing cells. CEA, a tumor associated antigen, is overexpressed in many cancer types, including gastrointestinal, breast, non-small cell lung, and thyroid cancers.