OBJECTIVES: Prostate cancer (PC) is the second leading cause of cancer death among men in the US. Approximately 165,000 men were diagnosed with new PC in the US in 2018. About 10-20 % will develop castration-resistant prostate cancer (CRPC) within 5 years of diagnosis; of these 70% will metastasize (mCRPC). Presence of visceral metastasis may affect survival. A cost-effectiveness analysis was conducted comparing enzalutamide (ENZ), abiraterone plus prednisone (ABI+PRD) and cabazitaxel plus prednisone (CAB+PRD) for visceral mCRPC post-docetaxel failure.

METHODS: Markov model with life-time horizon to estimate the incremental cost-effectiveness/utility ratios (ICER/ICUR) of direct medical costs per life-year (LY) and quality-adjusted life-year (QALY) gained from a US healthcare perspective (2018 US$; discount rate 3%/yr)). Inputs included drug and medical services costs, grade ≥3 adverse events with incidence >5%, physician follow up, blood and imaging tests. Kaplan-Meier curves from phase III trials were digitized and Weibull distributions were fitted to estimate overall (OS) and progression-free survival (PFS) transition probabilities. ICERs/ICURs were estimated in base case analyses, validated in probabilistic sensitivity analyses (PSA). Cost-effectiveness acceptability curves at various willingness-to-pay (WTP) thresholds were estimated.

RESULTS: Models estimated mortality rates in 3 years’ time of 98.7 % for ABI+PRD, 83.8 % for CAB+PRD, and 86.8 % for ENZ treated patients. In 1.5 years’ time, estimated PFS rates were 14.47 % for ENZ, 0.27 % for CAB+PRD, and 0.51 % for ABI+PRD treated patients). LYs and QALYs gained were 1.58 and 0.79 respectively for ENZ, 1.20 and 0.58 for ABI+PRD, and 1.48 and 0.61 for CAB+PRD. At total costs of $157,830 for ENZ, $235,853 for ABI+PRD, and $496,756 for CAB+PRD, ENZ was cost-saving comparing to other therapies. All validated in PSAs.

CONCLUSIONS: ENZ is cost-effectiveness compared to ABI+PRD and CAB+PRD. ABI+PRD is clinically less efficacious but less costly compared to CAB+PRD.