177Lu-DOTA-acidic oligopeptide conjugate

177Lu-DOTA-acidic oligopeptide conjugate is a hydroxyapatite-targeted radioligand therapy (RLT) being developed for the treatment of bone metastases. The therapeutic consists of an acidic oligopeptide ligand designed to bind specifically to hydroxyapatite, a mineral component of bone that becomes exposed in both osteolytic (e.g., breast cancer) and osteoblastic (e.g., prostate cancer) lesions but remains occluded in healthy bone by a cartilaginous sheath. This ligand is conjugated via a stable linker to a DOTA chelator carrying the beta-emitting radioisotope Lutetium-177 (177Lu). By selectively accumulating in bone lesions, the conjugate delivers localized cytotoxic radiation to tumor cells while sparing healthy tissues, including bone marrow. Preclinical data presented at AACR 2026 demonstrated high tumor-to-tissue ratios and significant suppression of tumor growth in mouse models, supporting its progression into IND-enabling studies.