Real-world outcomes of sipuleucel-T treatment in PROCEED, a prospective registry of men with metastatic castration-resistant prostate cancer.

The large registry, PROVENGE Registry for the Observation, Collection, and Evaluation of Experience Data (PROCEED)(NCT01306890), evaluated sipuleucel-T immunotherapy for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC).

PROCEED enrolled patients with mCRPC receiving 3 biweekly sipuleucel-T infusions. Assessments included overall survival (OS), serious adverse events (SAEs), cerebrovascular events (CVEs), and anticancer interventions (ACIs). Follow-up was for ≥3 years or until death or study withdrawal.

In 2011-2017, 1976 patients were followed for 46.6 months (median). The median age was 72 years, and the baseline median prostate-specific antigen level was 15.0 ng/mL; 86.7% were white, and 11.6% were African American. Among the patients, 1902 had 1 or more sipuleucel-T infusions. The median OS was 30.7 months (95% confidence interval [CI], 28.6-32.2 months). Known prognostic factors were independently associated with OS in a multivariable analysis. Among the 1255 patients who died, 964 (76.8%) died of prostate cancer (PC) progression. The median time from the first infusion to PC death was 42.7 months (95% CI, 39.4-46.2 months). The incidence of sipuleucel-T-related SAEs was 3.9%. The incidence of CVEs was 2.8%, and the rate per 100 person-years was 1.2 (95% CI, 0.9-1.6). The CVE incidence among 11,972 patients with mCRPC from the Surveillance, Epidemiology, and End Results-Medicare database was 2.8%; the rate per 100 person-years was 1.5 (95% CI, 1.4-1.7). One or more ACIs (abiraterone, enzalutamide, docetaxel, cabazitaxel, or radium 223) were received by 77.1% of the patients after sipuleucel-T; 32.5% and 17.4% of the patients experienced 1- and 2-year treatment-free intervals, respectively.

PROCEED provides contemporary survival data for sipuleucel-T-treated men in a real-world setting of new life-prolonging agents, which will be useful in discussing treatment options with patients and in powering future trials with sipuleucel-T. The safety and tolerability of sipuleucel-T in PROCEED were consistent with previous findings.

Cancer. 2019 Sep 04 [Epub ahead of print]

Celestia S Higano, Andrew J Armstrong, A Oliver Sartor, Nicholas J Vogelzang, Philip W Kantoff, David G McLeod, Christopher M Pieczonka, David F Penson, Neal D Shore, Jeffrey Vacirca, Raoul S Concepcion, Ronald F Tutrone, Luke T Nordquist, David I Quinn, Vahan Kassabian, Mark C Scholz, Matt Harmon, Robert C Tyler, Nancy N Chang, Hong Tang, Matthew R Cooperberg

Division of Medical Oncology, Departments of Medicine and Urology, University of Washington and Fred Hutchinson Cancer Research Center, Seattle, Washington., Division of Medical Oncology, Duke University Medical Center, Duke Cancer Institute, Duke University, Durham, North Carolina., Section of Hematology and Medical Oncology, Department of Medicine, Tulane Cancer Center and Tulane University School of Medicine, New Orleans, Louisiana., Division of Hematology/Oncology, Comprehensive Cancer Centers of Nevada, Las Vegas, Nevada., Department of Medicine, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, New York., Department of Surgery, Center for Prostate Disease Research at the Uniformed Services of Health Sciences, Bethesda, Maryland., Associated Medical Professionals, Syracuse, New York., Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee., Department of Urology, Carolina Urologic Research Center, Myrtle Beach, South Carolina., New York Cancer and Blood Specialists, New York, New York., Urology Associates PC, Nashville, Tennessee., Chesapeake Urology, Towson, Maryland., Department of Medical Oncology, GU Research Network, Omaha, Nebraska., Division of Medical Oncology, Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California., Advanced Urology, Atlanta, Georgia., Prostate Cancer Research Institute, Marina del Rey, California., Department of Biometrics, Dendreon Pharmaceuticals LLC, Seattle, Washington., Department of Medical Affairs, Dendreon Pharmaceuticals LLC, Seattle, Washington., Department of Urology, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California.