title: The PREVAIL trial of enzalutamide in men with chemotherapy-naïve, metastatic castration-resistant prostate cancer: Post hoc analysis of Korean patients.
abstract: This post hoc analysis evaluated treatment effects, safety, and pharmacokinetics of enzalutamide in Korean patients in the phase 3, double-blind, placebo-controlled PREVAIL trial.
  
  
  
  Asymptomatic or mildly symptomatic chemotherapy-naive men with metastatic castration-resistant prostate cancer that progressed on androgen deprivation therapy received 160 mg/d oral enzalutamide or placebo (1:1) until death or discontinuation due to radiographic progression or skeletal-related event and initiation of subsequent therapy. Coprimary end points were centrally assessed radiographic progression-free survival (rPFS) and overall survival (OS). Secondary end points included investigator-assessed rPFS, time to initiation of chemotherapy, time to prostate-specific antigen (PSA) progression, PSA response (≥50% decline), and time to skeletal-related event.
  
  
  
  Of 1,717 total patients, 78 patients were enrolled in Korea (enzalutamide, n=40; placebo, n=38). Hazard ratios (95% confidence interval) for enzalutamide versus placebo were 0.23 (0.02-2.24) for centrally assessed rPFS, 0.77 (0.28-2.15) for OS, 0.21 (0.08-0.51) for time to chemotherapy, and 0.31 (0.17-0.56) for time to PSA progression. A PSA response was observed in 70.0% of enzalutamide-treated and 10.5% of placebo-treated Korean patients. Adverse events of grade ≥3 occurred in 33% of enzalutamide-treated and 11% of placebo-treated Korean patients, with median treatment durations of 13.0 and 5.1 months, respectively. At 13 weeks, the plasma concentration of enzalutamide plus N-desmethyl enzalutamide was similar in Korean and non-Korean patients (geometric mean ratio, 1.04; 90% confidence interval, 0.97-1.10).
  
  
  
  In Korean patients, treatment effects and safety of enzalutamide were consistent with those observed in the overall PREVAIL study population (ClinicalTrials.gov Identifier: NCT01212991).
authors.affiliation: Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Choung-Soo
authors.initials: CS
authors.lastname: Kim
authors.affiliation: Biostatistics, Astellas Pharma Europe B.V., Leiden, The Netherlands.
authors.forename: Ad
authors.initials: A
authors.lastname: Theeuwes
authors.affiliation: Department of Urology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Dong Deuk
authors.initials: DD
authors.lastname: Kwon
authors.affiliation: Department of Urology, Severance Hospital, Urological Science Institute, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Young Deuk
authors.initials: YD
authors.lastname: Choi
authors.affiliation: Department of Urology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Byung Ha
authors.initials: BH
authors.lastname: Chung
authors.affiliation: Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Hyun Moo
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Urology, Center for Prostate Cancer, National Cancer Center, Goyang, Korea.
authors.forename: Kang Hyun
authors.initials: KH
authors.lastname: Lee
authors.affiliation: Department of Urology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Sang Eun
authors.initials: SE
authors.lastname: Lee
mesh_terms: D000230:Adenocarcinoma / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000556:secondary*; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000009:adverse effects / Q000097:blood / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001549:Benzamides; D018450:Disease Progression; D004311:Double-Blind Method; D006801:Humans; D007610:Kallikreins / Q000097:blood; D008297:Male; D008875:Middle Aged; D009570:Nitriles; D010669:Phenylthiohydantoin / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D017430:Prostate-Specific Antigen / Q000097:blood; D064129:Prostatic Neoplasms, Castration-Resistant / Q000097:blood / Q000000981:diagnostic imaging / Q000188:drug therapy*; D011859:Radiography; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D018931:Antineoplastic Agents, Hormonal; D001549:Benzamides; D009570:Nitriles; D010669:Phenylthiohydantoin; C540278:enzalutamide; C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: Antineoplastic agents; Castration-resistant prostatic neoplasms; Disease-free survival; MDV 3100; Republic of Korea