Enzalutamide Versus Bicalutamide for Nonmetastatic Castration-Resistant Prostate Cancer
Posted: Thursday, January 14, 2021
In the phase II STRIVE trial, enzalutamide demonstrated efficacy over bicalutamide in patients with metastatic or nonmetastatic castration-resistant prostate cancer; however, patients with nonmetastatic disease are frequently treated with bicalutamide. Celestia S. Higano, MD, of the University of Washington and Fred Hutchinson Cancer Research Center, Seattle, and colleagues conducted a study to highlight the clinical benefit of enzalutamide in this population. The subgroup analysis was presented during the virtual edition of the 2020 Society of Urologic Oncology (SUO) Annual Meeting (Abstract 133).
"Although this nonmetastatic castration-resistant prostate cancer study cohort is limited by a relatively small number of patients, these results are consistent with the clinical benefit of enzalutamide compared with placebo,” the investigators commented. “Enzalutamide is the only novel hormone therapy with demonstrated clinical benefit versus bicalutamide across prostate cancer disease states, including metastatic hormone-sensitive prostate cancer, nonmetastatic castration-resistant prostate cancer, and metastatic castration-resistant prostate cancer."
Patients with nonmetastatic castration-resistant prostate cancer were randomly assigned to receive daily enzalutamide (n = 70) or bicalutamide (n = 69). In both arms, androgen-deprivation therapy continued.
The risk of disease progression or death was reduced by 76% with enzalutamide versus bicalutamide (hazard ratio = 0.24; P < .0001). Across subgroups based on age (< 75 or ≥ 75), Eastern Cooperative Oncology Group performance status score (0 or 1), and Gleason score (≤ 7 or > 8), patients seemed to derive a progression-free survival benefit from treatment with enzalutamide. Compared with bicalutamide, treatment with enzalutamide reduced the risk of prostate-specific antigen progression by 82% (hazard ratio = 0.18; P < .0001). Fatigue (enzalutamide: 36.2%; bicalutamide: 21.7%), hot flush (20.3% vs. 2.9%), decreased appetite (17.4% vs. 5.8%), dizziness (17.4% vs. 4.3%), and nausea (17.4% vs. 13.0%) were the most frequently reported adverse events.
Disclosure: No information regarding conflicts of interest was provided.