Men with nonmetastatic, castration-resistant prostate cancer and a rapidly rising prostate-specific antigen (PSA) level are at high risk for metastasis. We hypothesized that enzalutamide, which prolongs overall survival among patients with metastatic, castration-resistant prostate cancer, would delay metastasis in men with nonmetastatic, castration-resistant prostate cancer and a rapidly rising PSA level.
In this double-blind, phase 3 trial, we randomly assigned, in a 2:1 ratio, men with nonmetastatic, castration-resistant prostate cancer and a PSA doubling time of 10 months or less who were continuing androgen-deprivation therapy to receive enzalutamide (at a dose of 160 mg) or placebo once daily. The primary end point was metastasis-free survival (defined as the time from randomization to radiographic progression or as the time to death without radiographic progression).
A total of 1401 patients (median PSA doubling time, 3.7 months) underwent randomization. As of June 28, 2017, a total of 219 of 933 patients (23%) in the enzalutamide group had metastasis or had died, as compared with 228 of 468 (49%) in the placebo group. The median metastasis-free survival was 36.6 months in the enzalutamide group versus 14.7 months in the placebo group (hazard ratio for metastasis or death, 0.29; 95% confidence interval, 0.24 to 0.35; P<0.001). The time to the first use of a subsequent antineoplastic therapy was longer with enzalutamide treatment than with placebo (39.6 vs. 17.7 months; hazard ratio, 0.21; P<0.001; such therapy was used in 15% vs. 48% of patients) as was the time to PSA progression (37.2 vs. 3.9 months; hazard ratio, 0.07; P<0.001; progression occurred in 22% vs. 69% of patients). At the first interim analysis of overall survival, 103 patients (11%) receiving enzalutamide and 62 (13%) receiving placebo had died. Adverse events of grade 3 or higher occurred in 31% of the patients receiving enzalutamide, as compared with 23% of those receiving placebo.
Among men with nonmetastatic, castration-resistant prostate cancer with a rapidly rising PSA level, enzalutamide treatment led to a clinically meaningful and significant 71% lower risk of metastasis or death than placebo. Adverse events were consistent with the established safety profile of enzalutamide. (Funded by Pfizer and Astellas Pharma; PROSPER ClinicalTrials.gov number, NCT02003924 .).
The New England journal of medicine. 2018 Jun 28 [Epub]
Maha Hussain, Karim Fizazi, Fred Saad, Per Rathenborg, Neal Shore, Ubirajara Ferreira, Petro Ivashchenko, Eren Demirhan, Katharina Modelska, De Phung, Andrew Krivoshik, Cora N Sternberg
From the Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago (M.H.), and Astellas Pharma, Northbrook (D.P., A.K.) - both in Illinois; Institut Gustave Roussy, University of Paris Sud, Villejuif, France (K.F.); the University of Montreal Hospital Center, Montreal (F.S.); Herlev Hospital, Herlev, Denmark (P.R.); Carolina Urologic Research Center, Myrtle Beach, SC (N.S.); State University of Campinas (Unicamp), Campinas, Brazil (U.F.); Kiev City Clinical Hospital 3, Kiev, Ukraine (P.I.); Pfizer, San Francisco (E.D., K.M.); and the Department of Medical Oncology, San Camillo Forlanini Hospital, Rome (C.N.S.).