Development and Characterization of Ga-68 Somatostatin Peptidomimetic Imaging Agents

Overexpression of somatostatin receptors (SSTRs) is strongly associated with various endocrine and non-endocrine tumors, where expression of SSTR2 (subtype 2) is the most prevalent. Currently, FDA approved SSTR-targeting imaging agents, Octeoscan and NeoTect, are peptide-based and designed only for Single Photon Emission Computed Tomography (SPECT). However, due to less bio-stability of peptides, many cases of false results have limited their applications. Hence, to overcome these outstanding challenges, there is an utmost need to develop enhanced imaging agents with: (1) improved bio-stability using peptidomimetics; (2) access to a more sensitive imaging technique--Positron Emission Tomography (PET). This project intends to discover highly potent and selective somatostatin (SRIF) peptidomimetics labeled with 68Ga, which may serve as the leads for developing small molecule-based imaging agents targeting at SSTR2 with improved detection sensitivity, and also providing PET tracers for those hospitals without cyclotron for PET tracer production. The specific aims of this two-year project include: (1) synthesis of peptidomimetic ligands and development of the labeling and analysis procedures for novel 68Ga tracers; (2) in vivo biodistribution and PET imaging studies of 68Ga labeled peptidomimetics will be evaluated in tumor (expressing SSTRs)-bearing mice model.

Project ID:PC9706-1043
External Project ID:NSC97-NU-7182-002