We evaluated the efficacy and safety of low-dose estramustine phosphate (EMP) in Japanese patients with castration-resistant prostate cancer (CRPC).
The present study was a single-arm, nonrandomized prospective study in which all patients received EMP orally twice daily for a total dose of 280 mg/day.
A total of 31 patients with CRPC were enrolled from December 2009 to December 2012 at 5 institutions in Japan. The primary endpoint was the prostate-specific antigen (PSA) response, defined as a 50% decline in the serum PSA level, confirmed ≥ 3 weeks later. The secondary endpoints included the objective response rate, interval to PSA progression, PSA response duration, progression-free survival, disease-specific survival, overall survival, safety, and quality-of-life assessment using the Functional Assessment of Cancer Therapy-Prostate scores.
Ten patients (32%) had a PSA response, and no patient had an objective response. The treatment was well tolerated, and the most frequent toxicities were grade 1 to 2 nausea/vomiting, anorexia, and gynecomastia. The median interval to PSA progression was 140 days (95% confidence interval [CI], 117-260 days). The PSA response duration was 119 days (95% CI, 49-219 days). The median progression-free survival was 213 days (95% CI, 167-422 days). The 3-year disease-specific survival and overall survival rates were 68. 6% (median not reached; 95% CI, 33 months to not available) and 59. 9% (median 42 months, 95% CI, 28 months to not available), respectively.
Low-dose EMP seems to be a safe treatment option with some efficacy in patients with CRPC.
Clinical genitourinary cancer. 2015 Sep 02 [Epub ahead of print]
Takahiro Inoue, Keiji Ogura, Mutushi Kawakita, Hiromasa Tsukino, Shusuke Akamatsu, Toshinari Yamasaki, Yoshiyuki Matsui, Takehiko Segawa, Yoshio Sugino, Toshiyuki Kamoto, Tomomi Kamba, Shiro Tanaka, Osamu Ogawa
Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan. , Department of Urology, Japanese Red Cross Otsu Hospital, Otsu, Japan. , Department of Urology, Kobe City Medical Center General Hospital, Kobe, Japan. , Department of Urology, Miyazaki University Faculty of Medicine, Miyazaki, Japan. , Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan. , Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan. , Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan. , Department of Urology, Kyoto City Hospital, Kyoto, Japan. , Department of Urology, Kobe City Medical Center General Hospital, Kobe, Japan. , Department of Urology, Miyazaki University Faculty of Medicine, Miyazaki, Japan. , Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan. , Translational Research Center, Kyoto University Hospital, Kyoto, Japan. , Department of Urology, Kyoto University Graduate School of Medicine, Kyoto, Japan.