anti-TAG-72 monoclonal antibody CC49-streptavidin conjugate

An immunoconjugate containing CC49, a monoclonal antibody (MAb) directed against the tumor-associated antigen (TAA) tumor-associated glycoprotein 72 (TAG-72), conjugated to streptavidin, a nonglycosylated homotetrameric protein that has four high affinity binding sites for biotin, with potential use in pre-targeted radioimmunotherapy (PRIT). Upon administration of anti-TAG-72 MAb CC49-streptavidin conjugate, the MAb moiety targets and binds to TAG-72 expressed on cancer cells. Upon subsequent administration of a biotin-based radioconjugate, such as yttrium Y 90 DOTA-biotin, the biotin moiety of the radioconjugate binds to the streptavidin moiety of MAb CC49-streptavidin conjugate, which localizes the biotin-conjugated radionuclide to the tumor site. Upon cellular internalization, a cytotoxic does of radiation may be specifically delivered to TAG-72-expressing tumor cells. TAG-72, a human pancarcinoma antigen, is overexpressed on a variety of cancer cell types.