A Phase 2/3 Prospective Multicenter Study of the Diagnostic Accuracy of Prostate Specific Membrane Antigen PET/CT with 18F-DCFPyL in Prostate Cancer Patients (OSPREY)

J Urol. 2021 Jul;206(1):52-61. doi: 10.1097/JU.0000000000001698. Epub 2021 Feb 26.


Purpose: Prostate specific membrane antigen-targeted positron emission tomography/computerized tomography has the potential to improve the detection and localization of prostate cancer. OSPREY was a prospective trial designed to determine the diagnostic performance of 18F-DCFPyL-positron emission tomography/computerized tomography for detecting sites of metastatic prostate cancer.

Materials and methods: Two patient populations underwent 18F-DCFPyL-positron emission tomography/computerized tomography. Cohort A enrolled men with high-risk prostate cancer undergoing radical prostatectomy with pelvic lymphadenectomy. Cohort B enrolled patients with suspected recurrent/metastatic prostate cancer on conventional imaging. Three blinded central readers evaluated the 18F-DCFPyL-positron emission tomography/computerized tomography. Diagnostic performance of 18F-DCFPyL-positron emission tomography/computerized tomography was based on imaging results compared to histopathology. In cohort A, detection of pelvic nodal disease (with specificity and sensitivity as co-primary end points) and of extrapelvic metastases were evaluated. In cohort B, sensitivity and positive predictive value for prostate cancer within biopsied lesions were evaluated.

Results: A total of 385 patients were enrolled. In cohort A (252 evaluable patients), 18F-DCFPyL-positron emission tomography/computerized tomography had median specificity of 97.9% (95% CI: 94.5%-99.4%) and median sensitivity of 40.3% (28.1%-52.5%, not meeting prespecified end point) among 3 readers for pelvic nodal involvement; median positive predictive value and negative predictive value were 86.7% (69.7%-95.3%) and 83.2% (78.2%-88.1%), respectively. In cohort B (93 evaluable patients, median prostate specific antigen 11.3 ng/ml), median sensitivity and positive predictive value for extraprostatic lesions were 95.8% (87.8%-99.0%) and 81.9% (73.7%-90.2%), respectively.

Conclusions: The primary end point for specificity was met while the primary end point for sensitivity was not. The high positive predictive value observed in both cohorts indicates that 18F-DCFPyL-positive lesions are likely to represent disease, supporting the potential utility of 18F-DCFPyL-positron emission tomography/computerized tomography to stage men with high-risk prostate cancer for nodal or distant metastases, and reliably detect sites of disease in men with suspected metastatic prostate cancer.

Keywords: molecular imaging; neoplasm metastasis; neoplasm staging; prostatic neoplasms.

Publication types

  • Clinical Trial, Phase II
  • Clinical Trial, Phase III
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Humans
  • Lysine / analogs & derivatives*
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Positron Emission Tomography Computed Tomography* / methods
  • Prospective Studies
  • Prostate-Specific Antigen*
  • Prostatic Neoplasms / diagnostic imaging*
  • Prostatic Neoplasms / pathology
  • Reproducibility of Results
  • Urea / analogs & derivatives*


  • 2-(3-(1-carboxy-5-((6-fluoropyridine-3-carbonyl)amino)pentyl)ureido)pentanedioic acid
  • Urea
  • Prostate-Specific Antigen
  • Lysine