Abiraterone acetate for metastatic castration-resistant prostate cancer after docetaxel failure: A randomized, double-blind, placebo-controlled phase 3 bridging study

OBJECTIVES - To evaluate the efficacy and safety of abiraterone acetate-prednisone versus placebo-prednisone in Asian metastatic castration-resistant prostate cancer patients who have failed docetaxel-based chemotherapy.

MATERIALS AND METHODS - In this double-blind, phase 3 study from China, 214 patients were randomized (2:1) to abiraterone acetate 1000 mg once daily plus prednisone 5 mg twice daily and placebo plus prednisone 5 mg twice daily in 28-day treatment cycles.

RESULTS - Abiraterone acetate-prednisone treatment significantly decreased prostate-specific antigen progression risk by 49%, with longer median time to prostate-specific antigen progression of 5. 55 months versus 2. 76 months in the placebo-prednisone group (hazard ratio 0. 506, P = 0. 0001, primary end-point). There was a strong trend for improved overall survival in the abiraterone acetate-prednisone group, with a 40% decrease in the risk of death (hazard ratio 0. 604, P = 0. 0597); however, median survival was not reached in either group because of the short follow-up period (12. 9 months) and limited number of observed death events. The prostate-specific antigen response rate was higher in the abiraterone-prednisone group (49. 7%) than in the placebo-prednisone group (14. 1%). A total of 37. 1% patients in this group had pain progression events compared with 50. 7% in the placebo-prednisone group. Abiraterone-prednisone significantly decreased the risk of pain progression by 50% (hazard ratio 0. 496, P = 0. 0014). The incidence of adverse events was similar between the two groups; the most common adverse events being anemia (25. 9% for abiraterone-prednisone vs 22. 5% for placebo-prednisone), hypokalemia (25. 9% and 11. 3%), bone pain (23. 8% and 21. 1%), hypertension (16. 1% and 12. 7%) and increased aspartate aminotransferase (14. 7% and 15. 5%), respectively.

CONCLUSIONS - Abiraterone-prednisone significantly delays disease and pain progression, and prostate-specific antigen, with a favorable benefit-risk ratio in Asian metastatic castration-resistant prostate cancer patients in the post-docetaxel setting.

International journal of urology : official journal of the Japanese Urological Association. 2016 Feb 15 [Epub ahead of print]

Yinghao Sun, Qing Zou, Zhongquan Sun, Changling Li, Chuanjun Du, Zhiwen Chen, Yuxi Shan, Yiran Huang, Jie Jin, Zhang Qun Ye, Liping Xie, Guowen Lin, Yi Feng, Peter De Porre, Weiping Liu, Dingwei Ye

Department of Urology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai, China. , Department of Oncology, Jiangsu Cancer Hospital, Nanjing, China. , Department of Urology, Huadong Hospital, Fudan University, Shanghai, China. , Department of Urology, Cancer Institute (Hospital), Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China. , Department of Urology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China. , Urology Center, Southwest Hospital, Third Military Medical University, Chongqing, China. , Department of Urinary Surgery, Second Affiliated Hospital of Soochow University, Suzhou, China. , Department of Urology, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China. , Department of Urology, Peking University First Hospital and Institute of Urology, Peking University, National Urological Cancer, Beijing, China. , Department of Urology, Tongji Medical College, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China. , Department of Urology, School of Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, China. , Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China. , Janssen Research & Development, Beijing, China. , Janssen Research & Development, Beerse, Belgium. , Janssen Research & Development, Beijing, China. , Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, China.

PubMed