Abiraterone acetate with prednisone and cabazitaxel as subsequent treatment after first-line docetaxel in metastatic castrate-resistant prostate cancer (mCRPC): Final efficacy and safety analysis of the CAPRO study.

Abstract

276 Background: Abiraterone acetate + prednisone (AA) and cabazitaxel (CB) have shown an improvement in overall survival after Docetaxel (DOC) in (mCRPC)1,2. There is little evidence about the optimal sequencing treatment in prospective trials. In this final analysis we now compare the efficacy of AA and CB as second line (2L) treatment in mCRPC patients (pts) in routine clinical practice (RCP) in Spain. Methods: The CAPRO study is a prospective multicenter national observational descriptive study. The primary endpoint was to describe the management in 2L mCRPC pts after DOC in RCP. bPFS (biochemical progression free survival) and PFS (clinical or radiological progression free survival) were assessed by the Kaplan-Meier method. Results: 150 patients were recruited (Jul 2013-Jan 2015). At median follow-up of 7.8 mo (IQR 4.2-12.8) 67% (n = 100) of the pts received AA, 29% (n = 44) CB, and 4% (n = 6) other treatments as 2L. PSA response > 50% was 47.3% and 32.3% for AA group and CB group respectively (p = 0.146). Median bPFS was similar between the AA and the CB group (9.19 mo [95% CI 6.84-11.55] vs 9.92 mo [95% CI 6.08-13.76]; hazard ratio 0.779 [95% CI 0·49–1.24]; p = 0·29), whereas median PFS was significantly longer in the AA group than in the CB group (8.74 mo [95% CI 6.54-10.94] vs 6.41 mo [95% CI 4.99-7.82]; hazard ratio 0·56 [95% CI 0·38–0·85]; p = 0·005). A difference was observed in bPFS and PFS depending on the time of progression to first line (during treatment, < 3 or more than 3 mo) for both AA and CB. The most common toxicities of special interest (all grades/grade 3–4 as % of pts) were fatigue (31/1% in the AA group vs 54/4% in the CB group), oedema (15/0% AA group vs 13/4% CB group), hypertension 7/1% AA group, diarrhea (8/0% AA group vs 31/4% CB group), vomits (9/2% AA group vs 11/0 CB group) and neutropenia 7/4% CB group. Conclusions: In this final analysis AA was the 2L treatment of choice in routine clinical practice in Spain during the period of time in which the study was conducted. PSA response and bPFS were similar between AA and CB, whereas PFS was significantly longer in the AA group. There were no new safety signals observed.