[⁶⁸Ga]Ga-FAP-2286, a novel promising theragnostic approach for PET/CT imaging in patients with various type of metastatic cancers

Fibroblast activation protein (FAP) has emerged as a promising target for diagnosis and therapeutic intervention due to high expression and accumulation in the stromal compartments of a variety of malignant tumors. FAP-2286 utilizes cyclic peptides with FAP-binding characteristics to enhance the retention of the imaging agent within tumors, in contrast to the small-molecule FAP inhibitors (FAPI) like FAPI-04/46. The aim of this study was to quantify the tumor uptake of [⁶⁸Ga] Gallium-FAP-2286 within primary solid tumors, adjacent excised tissues, and metastatic lesions.

In this prospective study, 21 patients (average age 51.9) with various diagnoses of remaining and metastatic cancers participated. Among them, six had metastatic sarcoma, and 14 had adenocarcinoma, including eight breast, two rectum, two lung, two pancreas, and one thyroid cases. The patients underwent a [⁶⁸Ga]Ga-FAP-2286 PET/CT scan. An hour post-administration of [⁶⁸Ga]Ga-FAP-2286, a visual assessment of whole body scans and semi-quantification of the PET/CT results were carried out. The standardized uptake values (SUV)_max of [⁶⁸Ga]Ga-FAP-2286 in tumor lesions and the tumor-to-background ratio (TBR) were then calculated.

The vital signs of the patients, such as heart rate, blood pressure, and temperature, were observed before, during, and after the diagnostic procedure during the 4-h follow-up. All individuals underwent the [⁶⁸Ga]Ga-FAP-2286 PET/CT scans without any signs of drug-associated pharmacological effects. The PET/CT scans displayed substantial absorption of [⁶⁸Ga]Ga-FAP-2286 in tumor lesions in all patients (100% (21/21)). Irrespective of the tumors’ origins (epithelial or mesothelium) and whether they exhibited local recurrence, distant recurrence, or metastatic lesions, the PET/CT scans revealed the uptake of [⁶⁸Ga]Ga-FAP-2286 in these lesions.

Overall, these data suggest that [⁶⁸Ga]Ga-FAP-2286 is a promising FAP derivative for efficient metastatic cancer diagnosis and being considered as a potential compound for therapeutic application in patients with advanced metastatic cancers.