Darolutamide in Nonmetastatic, Castration-Resistant Prostate Cancer.

Background: Darolutamide is a structurally unique androgen-receptor antagonist that is under development for the treatment of prostate cancer. We evaluated the efficacy of darolutamide for delaying metastasis and death in men with nonmetastatic, castration-resistant prostate cancer.

Methods: We conducted a randomized, double-blind, placebo-controlled, phase 3 trial involving men with nonmetastatic, castration-resistant prostate cancer and a prostate-specific antigen doubling time of 10 months or less. Patients were randomly assigned in a 2:1 ratio to receive darolutamide (600 mg [two 300-mg tablets] twice daily) or placebo while continuing androgen-deprivation therapy. The primary end point was metastasis-free survival, with the presence of metastasis determined by independent central review of radiographic imaging every 16 weeks.

Results: In total, 1509 patients underwent randomization (955 to the darolutamide group and 554 to the placebo group). In the planned primary analysis, which was performed after 437 primary end-point events had occurred, the median metastasis-free survival was 40.4 months with darolutamide, as compared with 18.4 months with placebo (hazard ratio for metastasis or death in the darolutamide group, 0.41; 95% confidence interval, 0.34 to 0.50; P<0.001). Darolutamide was also associated with benefits with regard to all secondary end points, including overall survival, time to pain progression, time to cytotoxic chemotherapy, and time to a symptomatic skeletal event. The incidence of adverse events that occurred or worsened during the treatment period and had a frequency of 5% or more or were of grade 3 or higher was similar in the two groups; all such events except fatigue occurred in less than 10% of patients in either group. The percentage of patients who discontinued the assigned regimen because of adverse events was 8.9% in the darolutamide group and 8.7% in the placebo group. Darolutamide was not associated with a higher incidence of seizures, falls, fractures, cognitive disorder, or hypertension than placebo.

Conclusions: Among men with nonmetastatic, castration-resistant prostate cancer, metastasis-free survival was significantly longer with darolutamide than with placebo. The incidence of adverse events was similar for darolutamide and placebo. (Funded by Bayer HealthCare and Orion Pharma; ARAMIS ClinicalTrials.gov number, NCT02200614.).