Retrospective analysis of the efficacy and safety of cabazitaxel treatment in castration resistant prostate cancer after docetaxel failure

Background: Cabazitaxel has been approved by FDA and EMEA for treatment of metastatic castration resistant prostate cancer (mCRPC) after failure of docetaxel based chemotherapy. Between June 2011 and November 2013 cabazitaxel was reimbursed for Polish mCRPC patients as a non-standard chemotherapy. The study objective was retrospective analysis of efficacy and safety data of mCRPC patients treated with cabazitaxel in this period. Material and methods: Collection of retrospective data on 48 consecutive mCRPC patients treated with cabazitaxel after docetaxel failure. Data on baseline characteristics, cancer history, and the efficacy and safety of cabazitaxel treatment were collected. Progression free survival (PFS) (radiological/clinical/biochemical) and overall survival (OS) were estimated by the Kaplan-Meier method. Objective response rate and clinical benefit were also assessed. Results: Forty-eight patients were included. Median PFS was 4.2 (95% CI 3.4 – 5.1) months, and median OS – 15.1 (95% CI 12.7 – 17.4) months. OS since docetaxel initiation in patients treated with cabazitaxel as second line chemotherapy (n=47) was 28,7 (95%CI 25,3-32,1) months. OS rates at 1, 2 and 3 years after first cabazitaxel cycle were 65%, 25% and 15%, respectively. In total, 289 cycles of cabazitaxel were administered (mean 6 per patient). There were 41 patients evaluable for biochemical response, 19/41 (46%) had an PSA decrease of at least 50% from baseline including 3/41, who had an initial PSA flare followed by a decrease of at least 50% from baseline. Adverse events comprised predominantly haematological (26 patients) and gastrointestinal (14 patients) toxicities. Ten SAEs were reported, including 1 death due to acute renal failure. Conclusion: Treatment with cabazitaxel of mCRPC patients after docetaxel failure is an important therapeutic option with acceptable toxicity with respect to clinical stabilization and possibly increased survival.