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

Purpose Current FDA-approved imaging modalities are inadequate for localizing prostate cancer biochemical recurrence (BCR). F-18-DCFPyL is a highly selective, small-molecule prostate-specific membrane antigen-targeted PET radiotracer. CONDOR was a prospective study designed to determine the performance of F-18-DCFPyL-PET/CT in patients with BCR and uninformative standard imaging. Experimental Design: Men with rising PSA >= 0.2 ng/mL after prostatectomy or >= 2 ng/mL above nadir after radiotherapy were eligible. The primary endpoint was correct localization rate (CLR), defined as positive predictive value with an additional requirement of anatomic lesion colocalization between (FDCFPyL)-F-18-PET/Cr and a composite standard of truth (SOT). The SOT consisted of, in descending priority (i) histopathology, (ii) subsequent correlative imaging findings, or (iii) post-radiation PSA response. The trial was considered a success if the lower bound of the 95% confidence interval (CI) for CLR exceeded 20% for two of three F-18-DCFPyL-PET/CT readers. Secondary endpoints included change in intended management and safety. Results: A total of 208 men with a median baseline PSA of 0.8 ng/mL (range: 0.2-98.4 ng/mL) underwent F-18-DCFPyL-PET/CT. The CLR was 84.8%-87.0% (lower bound of 95% CI: 77.8-80.4). A total of 63.9% of evaluable patients had a change in intended management after F-18-DCFPyL-PET/CT. The disease detection rate was 59% to 66% (at least one lesion detected per patient by F-18-DCFPyL-PET/CT by central readers). Conclusions: Performance of F-18-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 F-18-DCFPyL-PET/CT to localize disease in men with recurrent prostate cancer.