Pilot-phase PET/CT study targeting integrin αβ in pancreatic cancer patients using the cystine-knot peptide-based F-FP-R1-MG-F2.

Purpose: A novel cystine-knot peptide-based PET radiopharmaceutical, F-FP-R1-MG-F2 (knottin), was developed to selectively bind to human integrin αβ which is overexpressed in pancreatic cancer. The purpose of this study is to evaluate the safety, biodistribution, dosimetry, and lesion uptake of F-FP-R1-MG-F2 in patients with pancreatic cancer.

Methods: Fifteen patients (6 men, 9 women) with histologically confirmed pancreatic cancer were prospectively enrolled and underwent knottin PET/CT between March 2017 and February 2021 (ClinicalTrials.gov Identifier NCT02683824). Vital signs and laboratory results were collected before and after the imaging scans. Maximum standardized uptake values (SUV) and mean SUV (SUV) were measured in 24 normal tissues and pancreatic cancer lesions for each patient. From the biodistribution data, the organ doses and whole-body effective dose were calculated using OLINDA/EXM software.

Results: There were no significant changes in vital signs or laboratory values that qualified as adverse events or serious adverse events. At 1 h post-injection, areas of high F-FP-R1-MG-F2 uptake included the pituitary gland, stomach, duodenum, kidneys, and bladder (average SUV: 9.7-14.5). Intermediate uptake was found in the normal pancreas (average SUV: 4.5). Mild uptake was found in the lungs and liver (average SUV < 1.0). The effective dose was calculated to be 2.538 × 10 mSv/MBq. Knottin PET/CT detected all known pancreatic tumors in the 15 patients, although it did not detect small peri-pancreatic lymph nodes of less than 1 cm in short diameter in two of three patients who had lymph node metastases at surgery. Knottin PET/CT detected distant metastases in the lungs (n = 5), liver (n = 4), and peritoneum (n = 2), confirmed by biopsy and/or contrast-enhanced CT.

Conclusion: F-FP-R1-MG-F2 is a safe PET radiopharmaceutical with an effective dose comparable to other diagnostic agents. Evaluation of the primary pancreatic cancer and distant metastases with F-FP-R1-MG-F2 PET is feasible, but larger studies are required to define the role of this approach.

Trial Registration: NCT02683824.