Efficacy and Safety of Cabazitaxel Versus Abiraterone or Enzalutamide in Older Patients with Metastatic Castration-resistant Prostate Cancer in the CARD Study

Background: In the CARD study (NCT02485691), cabazitaxel significantly improved median radiographic progression-free survival (rPFS) and overall survival (OS) versus abiraterone/enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) who had previously received docetaxel and progressed ≤12 mo on the alternative agent (abiraterone/enzalutamide). Objective: To assess cabazitaxel versus abiraterone/enzalutamide in older (≥70 yr) and younger (<70 yr) patients in CARD. Design, setting, and participants: Patients with mCRPC were randomized 1:1 to cabazitaxel (25 mg/m² plus prednisone and granulocyte colony-stimulating factor) versus abiraterone (1000 mg plus prednisone) or enzalutamide (160 mg). Outcome measurements and statistical analysis: Analyses of rPFS (primary endpoint) and safety by age were prespecified; others were post hoc. Treatment groups were compared using stratified log-rank or Cochran–Mantel-Haenszel tests. Results and limitations: Of the 255 patients randomized, 135 were aged ≥70 yr (median 76 yr). Cabazitaxel, compared with abiraterone/enzalutamide, significantly improved median rPFS in older (8.2 vs 4.5 mo; hazard ratio [HR] = 0.58; 95% confidence interval [CI] = 0.38–0.89; p = 0.012) and younger (7.4 vs 3.2 mo; HR = 0.47; 95% CI = 0.30–0.74; p < 0.001) patients. The median OS of cabazitaxel versus abiraterone/enzalutamide was 13.9 versus 9.4 mo in older patients (HR = 0.66; 95% CI = 0.41–1.06; p = 0.084), and it was 13.6 versus 11.8 mo in younger patients (HR = 0.66; 95% CI = 0.41–1.08; p = 0.093). Progression-free survival, prostate-specific antigen, and tumor and pain responses favored cabazitaxel, regardless of age. Grade ≥3 treatment-emergent adverse events (TEAEs) occurred in 58% versus 49% of older patients receiving cabazitaxel versus abiraterone/enzalutamide and 48% versus 42% of younger patients. In older patients, cardiac adverse events were more frequent with abiraterone/enzalutamide; asthenia and diarrhea were more frequent with cabazitaxel. Conclusions: Cabazitaxel improved efficacy outcomes versus abiraterone/enzalutamide in patients with mCRPC after prior docetaxel and abiraterone/enzalutamide, regardless of age. TEAEs were more frequent among older patients. The cabazitaxel safety profile was manageable across age groups. Patient summary: Clinical trial data showed that cabazitaxel improved survival versus abiraterone/enzalutamide with manageable side effects in patients with metastatic castration-resistant prostate cancer who had previously received docetaxel and the alternative agent (abiraterone/enzalutamide), irrespective of age.