Objective: To estimate the cost-effectiveness of ipilimumab (3 mg/kg) compared with best supportive care (BSC) in pre-treated advanced melanoma patients.
Methods: The analysis was based on a US payer perspective and lifetime time horizon. A three-state Markov model was developed representing clinical outcomes, quality-of-life, and healthcare resource use of patients treated with ipilimumab and BSC. Transitions between states were modeled using overall and progression-free survival data from the MDX010-20 trial. Utility data were from a melanoma-specific study of the health state preferences of the general population. Disease management costs expressed in 2011 US Dollars were based on healthcare resource use observed in a US retrospective medical chart study. Uncertainty was analyzed using one-way and probabilistic sensitivity analyses.
Results: The gain in life years and QALYs from introducing ipilimumab over BSC were 1.88 years (95% CI = 1.62-2.20) and 1.14 (95% CI = 1.01-1.34) QALYs, respectively, over the lifetime time horizon. The estimated incremental cost of treating with ipilimumab vs BSC was $146,716 (95% CI = $130,992-$164,025). The estimated incremental cost-effectiveness ratios were $78,218 per life year gained and $128,656 per QALY gained. Ipilimumab was 95% likely to be cost-effective at a willingness-to-pay of $146,000/QALY.
Limitations: Ipilimumab's method of action causes a tumor response pattern that differs from the Response Evaluation Criteria in Solid Tumors upon which the model is based, leading to a potential under-estimate of quality-of-life of ipilimumab patients. Survival and QALY gains were related to the time horizon of the analysis. Sensitivity analyses indicated that qualitative conclusions regarding the cost-effectiveness of ipilimumab were unchanged when the method of quality adjustment and the time horizon were varied.
Conclusion: The analysis shows that the estimated cost-effectiveness of ipilimumab is within what has been shown to be acceptable to payers for oncology products in the US.