title: A phase 2 study of abiraterone acetate in Japanese men with metastatic castration-resistant prostate cancer who had received docetaxel-based chemotherapy.
abstract: OBJECTIVE
  In this Phase 2 multicenter study the efficacy and safety of oral abiraterone acetate (1000 mg/once daily) plus prednisolone (5 mg/twice daily) was evaluated in metastatic castration-resistant prostate cancer patients from Japan who had previously received docetaxel-based chemotherapy.
  
  
  METHODS
  Men (aged ≥20 years) with metastatic castration-resistant prostate cancer (prostate-specific antigen levels: ≥5 ng/ml), who had received 1 or 2 cytotoxic chemotherapies (with ≥1 regimen being docetaxel) for prostate cancer, were enrolled in this open-label, single-arm study. Primary efficacy endpoint was proportion of patients achieving a ≥50% prostate-specific antigen decline from baseline (prostate-specific antigen response rate) after 12-week treatment. Safety and pharmacokinetics were also assessed.
  
  
  RESULTS
  Confirmed prostate-specific antigen response rate by Week 12 was 28.3% (90% confidence interval: 17.6%; 41.1%) or 13 out of 46 (full analysis set) treated patients. However, total prostate-specific antigen response rate including confirmed and unconfirmed responses was 34.8% (90% confidence interval: 23.2%; 47.9%). Secondary efficacy endpoints and outcomes were: improvement in Eastern Cooperative Oncology Group performance status score by ≥1 unit: 7/16 patients (43.8%); objective radiographic response: complete response, partial response and stable disease in 0, 1/22 (4.5%) and 9/22 (40.9%) patients, respectively; pain palliation response: 9/16 (56.3%) patients. The most common adverse events (>20% patients) were upper respiratory tract infection (13/47, 27.7% patients) and hepatic function abnormal (10/47, 21.3% patients, Grade 3: 8.5%). All mineralocorticoid-related toxicities were Grade 1/2.
  
  
  CONCLUSIONS
  Abiraterone acetate plus prednisolone showed favorable efficacy in metastatic castration-resistant prostate cancer Japanese patients who had received chemotherapy. Abiraterone acetate plus prednisolone had an acceptable safety profile.
  
  
  BACKGROUND
  NCT01795703.
authors.affiliation: Department of Urology, Kitasato University School of Medicine, Kanagawa tsatoh@kitasato-u.ac.jp.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Satoh
authors.affiliation: Department of Urology, Yokohama City University Graduate School of Medicine, Kanagawa.
authors.forename: Hiroji
authors.initials: H
authors.lastname: Uemura
authors.affiliation: Department of Urology, Kidney Center, Tokyo Women's Medical University, Tokyo.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Tanabe
authors.affiliation: Division of Urology, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nishiyama
authors.affiliation: Department of Urology, Kurashiki Central Hospital, Okayama.
authors.forename: Akito
authors.initials: A
authors.lastname: Terai
authors.affiliation: Department of Urology, Kyushu University Graduate School of Medical Sciences, Fukuoka.
authors.forename: Akira
authors.initials: A
authors.lastname: Yokomizo
authors.affiliation: Department of Urology, Osaka City University Graduate School of Medicine, Osaka.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakatani
authors.affiliation: Janssen Pharmaceutical K.K., Tokyo.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Imanaka
authors.affiliation: Department of Urology, Hamamatsu University School of Medicine, Shizuoka.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ozono
authors.affiliation: Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Akaza
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000736:Androstenes / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000077143:Docetaxel; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011239:Prednisolone / Q000008:administration & dosage; D017430:Prostate-Specific Antigen / Q000378:metabolism; D064129:Prostatic Neoplasms, Castration-Resistant / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D043823:Taxoids / Q000627:therapeutic use
chemical_list: D000736:Androstenes; D043823:Taxoids; D000077143:Docetaxel; D011239:Prednisolone; D017430:Prostate-Specific Antigen; C089740:abiraterone
keywords: abiraterone acetate; chemotherapy; confirmed response, metastatic castration-resistant prostate cancer; prostate-specific antigen