Radiolabeled bombesin-derived compounds for in vivo imaging of gastrin-releasing peptide receptor (GRPR) and treatment of GRPR-related disorders

Abstract

To provide an improved radiotherapeutic agent for treating a disease associated with abnormal expression of a gastrin-releasing peptide receptor.SOLUTION: Provided is a bombesin-derived compound of formula Ia (RX-L-Xaa1-Gln-Trp-Ala-Val-Xaa2-His-Xaa3-ψ-Xaa4-NH2). RX includes a radionuclide chelator or trifluoroborate-containing prosthetic group. L is a linker. Xaa1 is D-Phe or the like, and Xaa2 is Gly or the like. Xaa3 is Leu or the like, and Xaa4 is Pro or the like. A symbol ψ denotes reduced peptide bond between Xaa3 and Xaa4. In the case where Xaa4 is Pro or the like, ψ is CH2-N, or in the case where Xaa4 is Phe or Nle, ψ is CH2 N(R). R is H or a C1-C5 linear or branched alkyl. Use of the compound as a contrast medium or therapeutic agent is also provided.SELECTED DRAWING: None

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