GRPr Theranostics: Current Status of Imaging and Therapy using GRPr Targeting Radiopharmaceuticals

Area of Science:

• Oncology
• Nuclear Medicine
• Radiopharmaceutical Chemistry

Background:

• Molecularly targeted therapies are gaining traction in oncology for combined diagnostic and therapeutic applications (theranostics).
• The gastrin-releasing peptide receptor (GRPr), a member of the bombesin family, is overexpressed in several tumor types, making it a significant theranostic target.
• Bombesin derivatives targeting GRPr have demonstrated favorable pharmacokinetic profiles, including rapid blood clearance and urinary excretion, alongside selective tumor binding.

Purpose of the Study:

• To review the theranostic applications of radiolabeled bombesin derivatives targeting the gastrin-releasing peptide receptor (GRPr).
• To highlight the use of the ⁶⁸Ga/¹⁷⁷Lu theranostic pair in GRPr-targeted imaging and therapy.
• To focus on the evaluation of these agents in preclinical and clinical settings, particularly for prostate and breast cancer.

Main Methods:

• Evaluation of preclinical and clinical studies involving radiolabeled bombesin derivatives.
• Assessment of agents targeting the gastrin-releasing peptide receptor (GRPr).
• Focus on theranostic applications using the ⁶⁸Ga/¹⁷⁷Lu radionuclide pair.

Main Results:

• Numerous radiolabeled bombesin derivatives targeting GRPr have been investigated.
• These agents exhibit rapid blood clearance and preferential urinary excretion.
• Selective binding to GRPr-expressing tumors has been consistently observed.

Conclusions:

• Radiolabeled GRPr-targeting bombesin derivatives are effective for theranostic applications in oncology.
• The ⁶⁸Ga/¹⁷⁷Lu pair is a predominant theranostic choice for GRPr-targeted imaging and therapy.
• Further development and application in prostate and breast cancer are supported by existing data.