Peptide-based radiopharmaceuticals for targeted tumor therapy

Abstract

A series of radiolabeled peptides have been designed and optimized for tumor-targeted peptide receptor radionuclide therapy (PRRT). Pre-clinical and clinical applications of PRRT have shown promising results on tumor response, overall survival, and quality of life in patients with several kinds of tumors. (90)Y-DOTA-TOC and (177)Lu-DOTA-TATE are two of the most common radiopharmaceuticals with symptomatic improvements and complete clinical data. In addition to somatostatin analogs, radiolabeled peptides have been developed to target the relative receptors overexpressed in the tumors, such as integrin αvβ3, gastrin-releasing peptide receptor (GRPR), melanocortin-1 receptor (MC1-R), cholecystokinin (CCK) receptor, and glucagon-like peptide-1 receptor (GLP-1R). Several strategies have been designed to improve the therapeutic efficacy of PRRT. For instance, radiolabeled peptides could be optimized by the amino acid modification and radionuclide selection. Healthy tissue protective agents and multi-cycle procedures could effectively decrease the side effects of PRRT. Furthermore, combination treatments, including PRRT combined with surgery, chemotherapeutic agents, or radiosensitizing agents could be applied to increase the effectiveness of PRRT. In this review, the current progress of peptide-based radiopharmaceuticals for tumor-targeted PRRT was summarized. Radiopharmaceuticals currently under clinical investigation were also described.