177Lu-DO3A-4B4

177Lu-DO3A-4B4 is a radiolabeled agent consisting of the radionuclide lutetium-177 conjugated to the small-molecule ligand DO3A-4B4. This compound is classified as a targeted radiopharmaceutical, in which the DO3A-4B4 peptide/ligand is used to selectively bind to a specific molecular target (not explicitly defined in the available data, but likely a receptor or biomarker over-expressed on certain tumor types) and deliver a therapeutic dose of beta radiation from the lutetium-177. There is insufficient publicly available information to definitively specify the precise molecular target, indication, or developer for 177Lu-DO3A-4B4. Based on naming convention and structure, it represents a targeted radioligand therapy similar in concept to lutetium-labeled peptides used in neuroendocrine tumors or prostate cancer, but the exact indication, mechanism, and developer are unclear from available sources.