Abstract 4139: Diagnostic performance of the F-18 labeled bombesin analog BAY 86-4367 in patients with primary prostate cancer

Abstract

Abstract Purpose: BAY 86-4367 is a new directly F-18 labeled, synthetic bombesin analog (3-Cyano-4-[18F]fluorobenzoyl-Ala(SO3H)-Ala(SO3H)-Ava-Gln-Trp-Ala-Val-NMeGly-His-Sta-Leu-NH2) with antagonistic properties, targeting Gastrin-releasing-peptide receptors (GRPr). The aim of this proof of mechanism (PoM) study is to demonstrate the feasibility, safety, tolerability, biodistribution and diagnostic performance of the PET tracer BAY 86-4367 in patients with primary prostate cancer. Methods: 5 patients with non-treated primary prostate cancer (PSA range 7 to 24 µg/l) were prospectively included in the study. All patients had standardized biopsy proven primary prostate cancer with Gleason scores ranging from 6 (3+3) to 9 (4+5). All patients had standardized sequential dynamic and static PET/CT using the F-18 labeled tracer BAY 86-4367 for primary staging. Safety data (vital signs, ECG, adverse effects) were assessed in all patients. Four patients had a prior PET/CT scan with F-18 choline. Patients were scheduled for prostatectomy of primary prostate cancer. Full prostate samples were histopathologically analyzed to further confirm the imaging localisation data. Results: The tracer BAY 86-4367 was well tolerated after injection of ∼300 MBq and a peptide mass dose <40 µg per patient. Safety data showed no relevant changes in the sequential blood values, electrocardiograms, urine testing or physical examination. Malignant lesions were depicted in 3/5 patients with the F-18 labeled BAY 86-4367 tracer. Biopsy verified the correct tumor localisation of these imaging findings. In two patients with histologically proven primary prostate cancer, BAY 86-4367 showed no active accumulation in the prostate. F-18 choline PET/CT was performed in 4/5 patients with positive signals in all 4 patients. Correlation with biopsy showed correct localisation of F-18 choline in tumor tissue. However, there was false positive F-18 choline accumulation in benign hyperplasia of the prostate. Conclusion: PET imaging with the F-18 labeled bombesin analog BAY 86-4367 is safe. The tracer BAY 86-4367 correctly depicts primary prostate cancer in a subset of patients. However, diagnostic accuracy of bombesin analogs in GRPr imaging needs to be further explored. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4139. doi:10.1158/1538-7445.AM2011-4139