Therapeutic Efficacy of a Bivalent Inhibitor of Prostate-Specific Membrane Antigen Labeled with Cu.

Radionuclide therapy targeting prostate-specific membrane antigen (PSMA) is promising for prostate cancer. We previously reported a ligand, Cu-CuSarbisPSMA, featuring 2 lysine-ureido-glutamate groups. Here, we report the therapeutic potential of Cu-CuSarbisPSMA. Growth of PSMA-positive xenografts was evaluated after treatment with Cu-CuSarbisPSMA or Lu-LuPSMA imaging and therapy (I&T). At 13 d after injection, tumor growth was similarly inhibited by the 2 tracers in a dose-dependent manner. Survival was comparable after single (30 MBq) or fractionated (2 × 15 MBq, 2 wk apart) administrations. Cu-CuSarbisPSMA is efficacious in a PSMA-expressing model of prostate cancer.