Enzalutamide for the treatment of nonmetastatic castration-resistant prostate cancer.

ABSTRACT

INTRODUCTION: Enzalutamide is the first characterized second-generation nonsteroidal androgen receptor inhibitor (ARi). Its efficacy has been established in several clinical trials evaluating its role in different settings of prostate cancer. Recently, enzalutamide has been approved for the treatment of nonmetastatic castration-resistant prostate cancer (nmCRPC). AREAS COVERED In this paper, the authors describe the chemical structure and pharmacologic characteristics of enzalutamide, providing a summary of clinical trials evaluating its efficacy and safety in prostate cancer patients. EXPERT OPINION Enzalutamide adds to the growing arsenal of ARi used in nmCRPC. An improvement in metastasis-free survival was observed with the use of these new treatment options; recently released preliminary data report also an OS benefit. These novel agents are generally well tolerated, but their safety profiles differ slightly. Since head-to-head comparisons between ARi in nmCRPC are lacking, the adverse events profile, as well as drug availability, costs, and considerations on treatment-sequencing, would most likely influence the selection of the individual agent in this setting. Further research is needed to improve treatment selection and clarify many unsolved issues. Abbreviations ARi nonsteroidal androgen receptor inhibitor; nmCRPC nonmetastatic castration resistant prostate cancer; ADT androgen deprivation therapy; OS overall survival; PSA prostate specific antigen; FDA Food and Drug Administration; AR Androgen Receptor; MFS metastasis free survival; PSA-DT PSA doubling time; HR hazard ratio; CI confidence interval; AEs adverse events; mCRPC metastatic castration resistant prostate cancer; mHSPC metastatic hormone-sensitive prostate cancer; rPFS radiographic progression-free survival; OR odds ratio.