Cabazitaxel in Metastatic Prostate Cancer

BACKGROUND The efficacy and safety of cabazitaxel, as compared with an androgen-signaling–targeted inhibitor (abiraterone or enzalutamide), in patients with metastatic castrationresistant prostate cancer who were previously treated with docetaxel and had progression within 12 months while receiving the alternative inhibitor (abiraterone or enzalutamide) are unclear. METHODS We randomly assigned, in a 1:1 ratio, patients who had previously received docetaxel and an androgen-signaling–targeted inhibitor (abiraterone or enzalutamide) to receive cabazitaxel (at a dose of 25 mg per square meter of body-surface area intravenously every 3 weeks, plus prednisone daily and granulocyte colony-stimulating factor) or the other androgen-signaling–targeted inhibitor (either 1000 mg of abiraterone plus prednisone daily or 160 mg of enzalutamide daily). The primary end point was imaging-based progression-free survival. Secondary end points of survival, response, and safety were assessed. RESULTS A total of 255 patients underwent randomization. After a median follow-up of 9.2 months, imaging-based progression or death was reported in 95 of 129 patients (73.6%) in the cabazitaxel group, as compared with 101 of 126 patients (80.2%) in the group that received an androgen-signaling–targeted inhibitor (hazard ratio, 0.54; 95% confidence interval [CI], 0.40 to 0.73; P<0.001). The median imagingbased progression-free survival was 8.0 months with cabazitaxel and 3.7 months with the androgen-signaling–targeted inhibitor. The median overall survival was 13.6 months with cabazitaxel and 11.0 months with the androgen-signaling–targeted inhibitor (hazard ratio for death, 0.64; 95% CI, 0.46 to 0.89; P=0.008). The median progression-free survival was 4.4 months with cabazitaxel and 2.7 months with an androgen-signaling–targeted inhibitor (hazard ratio for progression or death, 0.52; 95% CI, 0.40 to 0.68; P<0.001), a prostate-specific antigen response occurred in 35.7% and 13.5% of the patients, respectively (P<0.001), and tumor response was noted in 36.5% and 11.5% (P=0.004). Adverse events of grade 3 or higher occurred in 56.3% of patients receiving cabazitaxel and in 52.4% of those receiving an androgensignaling–targeted inhibitor. No new safety signals were observed. CONCLUSIONS Cabazitaxel significantly improved a number of clinical outcomes, as compared with the androgen-signaling–targeted inhibitor (abiraterone or enzalutamide), in patients with metastatic castration-resistant prostate cancer who had been previously treated with docetaxel and the alternative androgen-signaling–targeted agent (abiraterone or enzalutamide). (Funded by Sanofi; CARD ClinicalTrials.gov number, NCT02485691.)