Diagnostic Performance of 18F-DCFPyL-PET/CT in Men with Biochemically Recurrent Prostate Cancer: Results from the CONDOR Phase III, Multicenter Study

Abstract

PURPOSE: Current FDA-approved imaging modalities are inadequate for localizing prostate cancer biochemical recurrence (BCR). ¹⁸F-DCFPyL is a highly selective, small-molecule PSMA-targeted PET radiotracer. CONDOR was a prospective study designed to determine the performance of ¹⁸F-DCFPyL-PET/CT in patients with BCR and uninformative standard imaging. METHODS: Men with rising PSA {greater than or equal to}0.2 ng/mL after prostatectomy or {greater than or equal to}2 ng/mL above nadir after radiation therapy were eligible. The primary endpoint was correct localization rate (CLR) defined as positive predictive value with an additional requirement of anatomic lesion co-localization between ¹⁸F-DCFPyL-PET/CT and a composite standard of truth (SOT). The SOT consisted of, in descending priority: 1) histopathology, 2) subsequent correlative imaging findings, or 3) post-radiation PSA response. The trial was considered a success if the lower bound of the 95% confidence interval for CLR exceeded 20% for 2 of 3 ¹⁸F‑DCFPyL-PET/CT readers. Secondary endpoints included change in intended management and safety. RESULTS: 208 men with a median baseline PSA of 0.8 ng/mL (range: 0.2-98.4 ng/mL) underwent ¹⁸F-DCFPyL-PET/CT. The CLR was 84.8%-87.0% (lower bound of 95% CI: 77.8%-80.4%). 63.9% of evaluable patients had a change in intended management after ¹⁸F-DCFPyL-PET/CT. The disease detection rate was 59% to 66% (at least one lesion detected per patient by ¹⁸F-DCFPyL-PET/CT by central readers). CONCLUSION: Performance of ¹⁸F-DCFPyL-PET/CT achieved the study's primary endpoint, demonstrating disease localization in the setting of negative standard imaging and providing clinically meaningful and actionable information. These data further support the utility of ¹⁸F-DCFPyL-PET/CT to localize disease in men with recurrent prostate cancer.