Response to ketoconazole (keto) or docetaxel (D) following clinical progression on abiraterone acetate (AA) in castrate-resistant prostate cancer (CRPC).

196 Background: Patients (pts) with CRPC treated with keto often experience a rise in serum adrenal androgen levels upon progression and may subsequently respond to more potent adrenal suppression with AA. In contrast, pts treated with AA do not have a rise in serum androgen levels upon progression, and thus may not respond to further androgen synthesis inhibition with keto but require other treatment modalities such as chemotherapy instead. The goal of this analysis is to report the outcomes of pts with CRPC progressing on AA subsequently treated with either keto or D. Methods: Pts with chemotherapy-naive CRPC were treated on previously reported phase 1 and 2 trials of AA, with doses ranging from 250 to 1000 mg/day. Subsequent treatment following progression on AA was per individual investigator discretion, including treatment with either keto or D. Results: To date, following disease progression on AA, 6 and 14 pts have been subsequently treated with either keto or D respectively. Of the 14 pts treated ...