Definition

A radioimmunoconjugate containing daratumumab, a human immunoglobulin G1 kappa (IgG1k) monoclonal antibody directed against the cell surface glycoprotein CD38, conjugated to 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 of actinium Ac 225-DOTA-daratumumab, the monoclonal antibody moiety specifically targets and binds to cell surface antigen CD38. Upon binding, the radioisotope moiety delivers a cytotoxic dose of alpha radiation to CD38-expressing tumor cells. CD38, a cell surface glycoprotein, is expressed on various hematopoietic cells and is overexpressed on multiple myeloma (MM) cells.