Definition

A radioimmunoconjugate containing vofatamab, a human immunoglobulin G1 (IgG1) monoclonal antibody directed against the fibroblast growth factor receptor type 3 (FGFR3) labeled, via a chelating agent, with the alpha-emitting radioisotope actinium Ac 225, with potential antineoplastic activity. Upon administration of actinium Ac 225 vofatamab, the vofatamab moiety specifically targets and binds to FGFR3. Upon binding, the radioisotope moiety delivers a cytotoxic dose of alpha radiation to FGFR3-expressing tumor cells. FGFR3, a receptor tyrosine kinase upregulated or mutated in many tumor cell types, plays a key role in tumor cell proliferation.