Cost-effectiveness analysis of abiraterone and sipuleucel-T in metastatic castration-resistant prostate cancer

Objective: 10-20% of patients diagnosed with prostate cancer progress to metastatic castration-resistant prostate cancer (mCRPC). Recently, four novel therapies have been introduced for the treatment of mCRPC; of these, abiraterone and sipuleucel-T have been studied in the asymptomatic, pre-docetaxel population. Both have shown clinical benefits compared to placebo. This study evaluated the cost-effectiveness of abiraterone acetate and sipuleucel-T compared to prednisone in asymptomatic, pre-docetaxel mCRPC from a US societal perspective.

Methods: A Markov model was constructed to simulate stable disease, progressed disease, and death. Survival and event rates were derived from published clinical trial data. Costs were derived from the literature and government reimbursement schedules. Utilities were derived from the literature. Outcomes were measured as average cost-effectiveness ratios (ACER), incremental cost-effectiveness ratios (ICER), and net monetary benefits (NMB). One-way and probabilistic sensitivity analyses were conducted to test the robustness of the model.

Results: The base-case ACER was $114k/QALY for abiraterone, $85k/QALY for sipuleucel-T, and $31k/QALY for prednisone. The base-case ICER was $389k/QALY for abiraterone, $547k/QALY for sipuleucel-T. Prednisone dominates both abiraterone and sipuleucel-T in terms of NMB at WTP thresholds of < $400k. One-way sensitivity analyses revealed that the model was most sensitive to overall survival and utility inputs. Probabilistic sensitivity analyses showed abiraterone to be cost-effective > 50% of the time at a WTP of >$400k, while sipuleucel-T was cost-effective > 50% of the time at a WTP of >$270k.

Conclusion: Neither abiraterone nor sipuleucel-T was found to be cost-effective compared to prednisone in the treatment of asymptomatic, pre-docetaxel mCRPC.

Keywords
prostate cancer, metastatic, castration-resistant, abiraterone, sipuleucel-T, cost-effectiveness