Definition

A radioimmunoconjugate comprised of M5A, a humanized monoclonal antibody directed against carcinoembryonic antigen-related cell adhesion molecule 5 (CEA or CEACAM5), conjugated with the bifunctional, macrocyclic chelating agent tetra-azacyclododecanetetra-acetic acid (DOTA), and labeled with the alpha-emitting radioisotope actinium Ac 225, with potential antineoplastic activity. Upon administration, the monoclonal antibody moiety of actinium Ac 225-DOTA-anti-CEA monoclonal antibody M5A specifically targets and binds to CEA, thereby delivering a cytotoxic dose of alpha radiation to CEA-expressing tumor cells. CEA, a tumor-associated antigen (TAA) and a member of the CEA family of proteins, plays a key role in cell migration, cell invasion and cell adhesion, and is overexpressed by a variety of cancer types.