fluorine F-18 AlF-NOTA-BCP137

Fluorine F-18 AlF-NOTA-BCP137 is a radiopharmaceutical imaging agent consisting of a bicyclic peptide (BCP137) linked to the radionuclide fluorine-18 (18F) through the macrocyclic chelating agent NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) using aluminum fluoride (AlF) chemistry. This PET tracer targets CD137 (4-1BB), a receptor expressed on activated T cells, enabling noninvasive visualization and quantification of tumor-infiltrating activated T cells in the tumor microenvironment. The agent was developed for evaluating immune checkpoint inhibitor therapy responses in cancer patients, particularly those with hepatocellular carcinoma. Preclinical studies demonstrated that tracer uptake predicted early therapeutic responses to combination immunotherapies and correlated positively with increased survival rates in tumor-bearing mice. Initial clinical evaluation in five hepatocellular carcinoma patients showed the tracer could stratify patients into immunotherapy responders and nonresponders based on tumor-to-muscle standardized uptake value ratios. The imaging is performed approximately 50 minutes after intravenous injection using whole-body PET/CT scanning. Development was led by researchers at Shandong First Medical University in Jinan, China.