A proprietary recombinant 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 of anti-CD33/CD3 BiTE antibody AMG 330, this bispecific antibody 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 neoplastic cells in patients with acute myeloid leukemia.