actinium Ac 225-ABD147

A radioimmunoconjugate consisting of ABD147, an antibody fragment directed against the tumor-associated antigen (TAA) delta-like protein 3 (DLL3) conjugated with a linker-chelator to the alpha-emitting radioisotope actinium Ac 225 (225Ac), with potential antineoplastic activity. Upon administration of actinium Ac 225-ABD147, ABD147 targets and binds to DLL3 on DLL3-expressing tumor cells. Upon binding, the radioisotope moiety delivers a cytotoxic dose of alpha radiation to DLL3-expressing tumor cells. DLL3, a Notch pathway protein, is overexpressed on a variety of cancer cell types. It plays a key role in embryonic development and in tumor initiation and proliferation.