Enzalutamide versus bicalutamide in patients with nonmetastatic castration-resistant prostate cancer: a prespecified subgroup analysis of the STRIVE trial

David F Penson,Andrew J Armstrong,Carl A Olsson,Raoul S Concepcion,Lawrence I Karsh,William Duggan,Gabriel P Haas,Curtis J Dunshee,Neeraj Agarwal,Celestia S Higano,Qi Shen,Jennifer Sugg

doi:10.1038/s41391-021-00465-7

Abstract

BackgroundIn the phase 2, randomized, double-blind STRIVE trial, enzalutamide significantly reduced the risk of prostate cancer progression or death versus bicalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) and nonmetastatic CRPC (nmCRPC). The objective of this protocol-specified subgroup analysis of STRIVE was to investigate the benefit of enzalutamide versus bicalutamide specifically in patients with nmCRPC.MethodsPatients (N = 139) were stratified by disease stage and randomized to enzalutamide 160 mg/day plus androgen deprivation therapy (ADT; n = 70) or bicalutamide 50 mg/day plus ADT (n = 69).ResultsBaseline characteristics of patients with nmCRPC were comparable between groups. At a median of 17 months follow-up, enzalutamide reduced the risk of progression or death by 76% versus bicalutamide in patients with nmCRPC (hazard ratio [HR], 0.24; 95% CI 0.14–0.42). Enzalutamide reduced risk of prostate-specific antigen progression by 82% versus bicalutamide in patients with nmCRPC (HR, 0.18; 95% CI 0.10–0.34). The most frequently reported adverse events by patients receiving enzalutamide were fatigue (36.2%), hot flush (20.3%), decreased appetite (17.4%), dizziness (17.4%), and nausea (17.4%).ConclusionsThis STRIVE subgroup analysis of patients with nmCRPC illustrates the benefit of enzalutamide in reducing the risk of progression or death versus bicalutamide in patients with nmCRPC.Trial registrationClinicalTrials.gov identifier NCT01664923.

Highlights

In the phase 2, randomized, double-blind STRIVE trial, enzalutamide significantly reduced the risk of prostate cancer progression or death versus bicalutamide, in patients with metastatic castration-resistant prostate cancer and nonmetastaticCRPC [1]
The objective of this prespecified subgroup analysis of STRIVE was to investigate the clinical benefit of enzalutamide versus bicalutamide in patients with nonmetastatic CRPC (nmCRPC) by reporting progression-free survival (PFS), time to prostate-specific antigen progression (TTPP), and associated safety data not previously reported in METHODS The STRIVE trial, described previously [1], was a randomized, double-blind, phase 2 study of enzalutamide 160 mg/day plus androgen deprivation therapy (ADT; n = 70) versus bicalutamide 50 mg/day plus ADT (n = 69) in patients with nmCRPC or metastatic castration-resistant prostate cancer (mCRPC)
The STRIVE trial reported enzalutamide improved both median PFS (19.4 months vs 5.7 months; P < 0.0001) and median TTPP versus bicalutamide, consistently in patients with nmCRPC and mCRPC [1]

Summary

BACKGROUND

In the phase 2, randomized, double-blind STRIVE trial, enzalutamide significantly reduced the risk of prostate cancer progression or death versus bicalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) and nonmetastatic CRPC (nmCRPC). The objective of this protocol-specified subgroup analysis of STRIVE was to investigate the benefit of enzalutamide versus bicalutamide in patients with nmCRPC. Enzalutamide reduced risk of prostate-specific antigen progression by 82% versus bicalutamide in patients with nmCRPC (HR, 0.18; 95% CI 0.10–0.34). CONCLUSIONS: This STRIVE subgroup analysis of patients with nmCRPC illustrates the benefit of enzalutamide in reducing the risk of progression or death versus bicalutamide in patients with nmCRPC.

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DISCUSSION