Organ protection in PSMA-targeted radionuclide therapy of prostate cancer

A method of reducing radiation exposure of a non-cancerous tissue of a patient diagnosed with prostate cancer, the method comprising:

• administering to the patient a compound comprising a radionuclide and a recognition moiety for Prostate Specific Membrane Antigen (“PSMA”), the compound binding to both cancerous prostate tissue and the non-cancerous tissue, and,
• after a waiting period of 1 hour to 60 hours, administering an agent in an amount sufficient to cause a displacement of the bound compound from the binding sites in the non-cancerous tissue by binding of the agent thereto while retaining the radionuclide in the cancerous tissue thereby reducing the exposure of the non-cancerous tissue to the radionuclide;
• wherein:
• the binding sites are attached to both the agent and the compound, and
• the agent has a different chemical structure from the compound, or
• the agent has the same chemical structure as the compound absent the radionuclide, and
• the agent comprises a recognition moiety for PSMA:
• the compound is a Glu-urea-based PSMA ligand;
• and the agent comprises a Glu-urea-based PSMA ligand, a phosphinyl containing moiety, 7-(L-2-amino-2-carboxyethylthio)-2-(2,2-dimethylcyclopropanecarboxamide)-2-heptenoic acid, 2-(phosphonomethyl)pentanedioic acid, or 2-(3-mercaptopropyl)pentanedioic acid (2-MPPA).