Definition

An immunoconjugate consisting of a humanized monoclonal antibody that is engineered to contain cysteine residues that are conjugated to the synthetic, DNA cross-linking, pyrrolobenzodiazepine dimer SGD-1882, via the protease-cleavable linker maleimidocaproyl-valine-alanine dipeptide, with potential antineoplastic activity. The monoclonal antibody portion of the vadastuximab talirine specifically binds to the cell surface antigen CD33. This causes the internalization of vadastuximab talirine, and the release of the cytotoxic moiety SGD-1882. SGD-1882 binds to and crosslinks DNA, which results in both cell cycle arrest and the induction of apoptosis in CD33-expressing tumor cells. CD33, a transmembrane receptor, is expressed on myeloid leukemia cells.