Activity of cabazitaxel after docetaxel and abiraterone acetate therapy in patients with castration-resistant prostate cancer

The efficacy of cabazitaxel (CAB) after abiraterone acetate (AA) inmetastatic castration-resistant prostate cancer (mCRPC) is unknown. Because both affect the androgen receptor (AR) there is a concern about the activity of this sequence.We retrospectively demonstrated a prostate-specific antigen (PSA) response of 31.5%, partial response of 15.3%, and median survival of 8.2 months with CAB. CAB was active after AA and docetaxel in mCRPC. Patients and Methods: One hundred thirty mCRPC patients received AA after docetaxel treatment in compassionate programs. Of them, 24 (18.4%) subsequently received CAB. We retrospectively reviewed their data using conventional methods. Results: Twenty-four patients received a median of 4 (range, 1-13) CAB cycles. Nineteen (79.1%) of them received primary prophylaxis with growth factors. Median patient characteristics were: age 65 (range, 57-85) years; Gleason score: 8 (range, 6-10); and PSA: 128.1 (range, 0.01-1700) ng/mL. A PSA response (≥ 50% decrease from baseline) occurred in 6 (31.5%) of 19 evaluable patients (95% confidence interval [CI], 11.8-54.2%). CAB therapy obtained a partial response in 2 of the 13 (15.3%) evaluable patients (95% CI, 2.9-45.4%). Median survival from initiation of CAB was 8.2 (95% CI, 3.34-13.05) months, from AA 16.1 (95% CI, 11.56-20.64) and from docetaxel 32.0 (95% CI, 11.56-39.69). Conclusion: A limited number of patients with mCRPC received CAB after docetaxel and AA treatment. In this selected population, CAB was active.