Synthesis and Evaluation of Novel C-X-C Chemokine Receptor 4-Targeted Radiotracers for Oncological Imaging

C-X-C chemokine receptor 4 (CXCR4), which is overexpressed in various cancers, has been considered as an important target for cancer theranostics. In this study, a series of small molecule radiotracers targeting CXCR4 were developed and obtained with high radiochemical purity (>95%). Among seven radiotracers, [68Ga]Ga-SDNUM04 showed favorable binding affinity (Kd = 32.21 ± 0.71 nM), tumor uptake (SUVmean = 0.63 ± 0.02) and tumor-to-liver ratio (T/L = 1.07). In addition, [68Ga]Ga-SDNUM04 exhibited satisfactory imaging outcomes and biodistribution properties in various CXCR4-positive tumors, making it a promising radiotracer for the clinical diagnosis of CXCR4-positive cancers.