Phase III non-inferiority study of cabazitaxel (C) 20 mg/m2 (C20) versus 25 mg/m2 (C25) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) previously treated with docetaxel (D)

5008Background: The Phase III TROPIC study (NCT00417079) reported a significant improvement in overall survival (OS) for C plus prednisone (P) (25 mg/m2once every 3 weeks plus 10 mg orally once daily) versus mitoxantrone plus P (Hazard Ratio [HR] 0.70; P < 0.0001) in pts with mCRPC previously treated with D. This PROSELICA study (NCT01308580) was designed to determine the relative efficacy and safety profile of C20 plus P compared with C25 plus P. Methods: In this randomized, open-label, multinational phase III study, pts with mCRPC and ECOG performance status 0–2, who progressed after treatment with D, were stratified (ECOG, RECIST, region) and randomized 1:1 to C20 or C25. To show that C20 could preserve ≥ 50% of the efficacy benefit showed by C25 in TROPIC, the HR of C20 vs C25 for the primary endpoint OS could not exceed 1.214 under 1-sided 98.89% confidence level adjusted after interim analyses. Secondary endpoints included progression free survival (PFS), safety, PSA, pain and tumor responses and qu...