Peptide receptor radionuclide therapy: current status and future directions

Results from preclinical and clinical multicenter studies with radiolabeled somatostatin ana-logues for peptide receptor radionuclide therapy(PRRT) already have shown an effective therapeutic response. The combination of different therapy modalities holds interest as a means of improving the clinical therapeutic effects of radiolabeled peptides. The combination of different radionuclides, such as ¹⁷⁷Lu- and ⁹⁰Y-labeled somatostatin analogues, to reach a wider tumor region of high curability, has been described. A variety of other peptide-based radioligands, such as bombesin and NPY analogues, receptors for which are expressed on common cancers such as prostate and breast cancer, are currently under development. Multireceptor tumor targeting using the combination of bombesin and NPY analogues is promising for scintigraphy and PRRT of breast carcinomas and their lymph node metastases.