Cost per median overall survival month associated with abiraterone acetate and enzalutamide for treatment of patients with metastatic castration-resistant prostate cancer

Objective: To calculate costs per median overall survival (OS) month in chemotherapy-naïve patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone acetate plus prednisone (AA?+?P) or enzalutamide. Methods: Median treatment duration and median OS data from published Phase 3 clinical trials and prescribing information were used to calculate costs per median OS month based on wholesale acquisition costs (WACs) for patients with mCRPC treated with AA?+?P or enzalutamide. Sensitivity analyses were performed to understand how variations in treatment duration and treatment-related monitoring recommendations influenced cost per median OS month. Cost-effectiveness estimates of other Phase 3 trial outcomes were also explored: cost per month of chemotherapy avoided and per median radiographic progression-free survival (rPFS) month. Results: The results demonstrated that AA?+?P has a lower cost per median OS month than enzalutamide ($3231 vs 4512; 28% reduction), based on the following assumptions: median treatment duration of 14 months for AA?+?P and 18 months for enzalutamide, median OS of 34.7 months for AA?+?P and 35.3 months for enzalutamide, and WAC per 30-day supply of $8007.17 for AA?+?P vs $8847.98 for enzalutamide. Sensitivity analyses showed that accounting for recommended treatment-related monitoring costs or assuming identical treatment durations for AA?+?P and enzalutamide (18 months) resulted in costs per median OS month 8–27% lower for AA?+?P than for enzalutamide. Costs per month of chemotherapy avoided were $4448 for AA?+?P and $5688 for enzalutamide, while costs per month to achieve median rPFS were $6794 for AA?+?P and $7963 for enzalutamide. Conclusions: This cost-effectiveness analysis demonstrated that costs per median OS month, along with costs of other Phase 3 trial outcomes, were lower for AA?+?P than for enzalutamide. The findings were robust to sensitivity analyses. These results have important implications for population health decision-makers evaluating the relative value of therapies for mCRPC patients.