Asian Journal of Urology (Apr 2017)

A phase 3, double-blind, randomized placebo-controlled efficacy and safety study of abiraterone acetate in chemotherapy-naïve patients with mCRPC in China, Malaysia, Thailand and Russia

  • Dingwei Ye,
  • Yiran Huang,
  • Fangjian Zhou,
  • Keji Xie,
  • Vsevolod Matveev,
  • Changling Li,
  • Boris Alexeev,
  • Ye Tian,
  • Mingxing Qiu,
  • Hanzhong Li,
  • Tie Zhou,
  • Peter De Porre,
  • Margaret Yu,
  • Vahid Naini,
  • Hongchuan Liang,
  • Zhuli Wu,
  • Yinghao Sun

DOI
https://doi.org/10.1016/j.ajur.2017.01.002
Journal volume & issue
Vol. 4, no. 2
pp. 75 – 85

Abstract

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Objective: This double-blind, placebo-controlled phase 3 study was designed to compare efficacy and safety of abiraterone acetate + prednisone (abiraterone) to prednisone alone in chemotherapy-naïve, asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer (mCRPC) patients from China, Malaysia, Thailand and Russia. Methods: Adult chemotherapy-naïve patients with confirmed prostate adenocarcinoma, Eastern Cooperative Oncology Group (ECOG) performance status (PS) grade 0–1, ongoing androgen deprivation (serum testosterone <50 ng/dL) with prostate specific antigen (PSA) or radiographic progression were randomized to receive abiraterone acetate (1000 mg, QD) + prednisone (5 mg, BID) or placebo + prednisone (5 mg, BID), until disease progression, unacceptable toxicity or consent withdrawal. Primary endpoint was improvements in time to PSA progression (TTPP). Results: Totally, 313 patients were randomized (abiraterone: n = 157; prednisone: n = 156); and baseline characteristics were balanced. At clinical cut-off (median follow-up time: 3.9 months), 80% patients received treatment (abiraterone: n = 138, prednisone: n = 112). Median time to PSA progression was not reached with abiraterone versus 3.8 months for prednisone, attaining 58% reduction in PSA progression risk (HR = 0.418; p < 0.0001). Abiraterone-treated patients had higher confirmed PSA response rate (50% vs. 21%; relative odds = 2.4; p < 0.0001) and were 5 times more likely to achieve radiographic response than prednisone-treated patients (22.9% vs. 4.8%, p = 0.0369). Median survival was not reached. Most common (≥10% abiraterone vs. prednisone-treated) adverse events: bone pain (7% vs. 14%), pain in extremity (6% vs. 12%), arthralgia (10% vs. 8%), back pain (7% vs. 11%), and hypertension (15% vs. 14%). Conclusion: Interim analysis confirmed favorable benefit-to-risk ratio of abiraterone in chemotherapy-naïve men with mCRPC, consistent with global study, thus supporting use of abiraterone in this patient population.

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