Definition

A radioimmunoconjugate composed of the F(ab’)2 fragment of monoclonal antibody MX35 targeting the sodium-dependent phosphate transport protein 2b (NaPi2b; SLC34A2) labeled with the alpha-emitting radionuclide astatine (At) 211 (211At), with potential antineoplastic activity. Upon administration of astatine At 211 F(ab’)2 MX35, the F(ab’)2 MX35 moiety targets and binds to NaPi2b-expressing tumor cells, thereby delivering a cytotoxic dose of alpha radiation directly to the NaPi2b-expressing tumor cells. NaPi2b, a multi-transmembrane, sodium-dependent phosphate transporter, is highly expressed in certain types of tumor cells.