Exploring the optimal sequence of abiraterone and enzalutamide in patients with chemotherapy‐naïve castration‐resistant prostate cancer: The Kyoto‐Baltimore collaboration. (28th April 2017)

• Record Type: Journal Article
• Authors: Terada, Naoki; Maughan, Benjamin L; Akamatsu, Shusuke; Kobayashi, Takashi; Yamasaki, Toshinari; Inoue, Takahiro; Kamba, Tomomi; Ogawa, Osamu; Antonarakis, Emmanuel S
• Is Part Of: International journal of urology. Volume 24:Number 6(2017)
• Page Start: 441
• Page End: 448
• Publication Date: 2017-04-28
• Subjects: abiraterone -- castration resistant -- enzalutamide -- prostate cancer -- sequential therapy; Urology -- Periodicals; Genitourinary organs -- Periodicals; Urologic Diseases -- Periodicals; 616.6005
• DOI: 10.1111/iju.13346
• Languages: English
• ISSNs: 0919-8172

Abstract

Abstract : Objectives: To evaluate and compare the efficacy of sequential treatment with abiraterone followed by enzalutamide or vice versa for castration‐resistant prostate cancer. Methods: We retrospectively evaluated data on 198 consecutive chemotherapy‐naïve patients who had received both abiraterone and enzalutamide for castration‐resistant prostate cancer at Kyoto University Hospital (including satellite hospitals) and at Johns Hopkins Cancer Center. Prostate‐specific antigen progression‐free survival and overall survival in patients treated with sequential abiraterone‐to‐enzalutamide versus enzalutamide‐to‐abiraterone without intervening therapies were compared. Results: Overall, 113 patients were treated with the abiraterone‐to‐enzalutamide sequence and 85 with the enzalutamide‐to‐abiraterone sequence. Median prostate‐specific antigen progression‐free survival was not significantly different between abiraterone and enzalutamide in the first‐line setting (hazard ratio 0.88, 95% confidence interval 0.66–1.19, P = 0.412), but there was an advantage favoring enzalutamide compared with abiraterone in the second‐line setting (hazard ratio 0.67, 95% confidence interval 0.49–0.91, P = 0.009). Furthermore, the combined prostate‐specific antigen progression‐free survival was significantly longer in the abiraterone‐to‐enzalutamide sequence than in the enzalutamide‐to‐abiraterone sequence (hazard ratio 0.56, 95% confidence interval 0.41–0.76, P < 0.001). The difference was significant even in multivariate analyses (hazard ratio 0.65, 95% confidence interval 0.42–0.99, P = 0.044). There was no statistical difference in overall survival between the two sequences in univariate (hazard ratio 0.88, 95% confidence interval 0.53–1.43, P = 0.599) and multivariate analyses (hazard ratio 0.81, 95% confidence interval 0.49–1.35, P = 0.427). Conclusions: The abiraterone‐to‐enzalutamide sequence might have more favorable efficacy in terms of combined prostate‐specific antigen progression‐free survival than the enzalutamide‐to‐abiraterone sequence, although no differences in overall survival were observed. This could possibly be attributable to longer prostate‐specific antigen progression‐free survival with second‐line enzalutamide compared with abiraterone.