ABSTRACT: Background:We evaluated the cost-effectiveness of nivolumab versus everolimus in patients with advanced renal cell carcinoma (RCC) from a US payer perspective. Methods:A partitioned survival model consisting of three health states, progression-free survival (PFS), progressive disease, and death, was developed to evaluate the cost-effectiveness of intravenous nivolumab versus oral everolimus over a lifetime. The proportion of patients in each state was calculated based on parametric distributions fitted to PFS and overall survival (OS) data from CheckMate 025 (N = 821), a large randomized phase 3 trial of nivolumab versus everolimus for advanced RCC. Health state utility data were derived from CheckMate 025 EQ-5D data. Scenario analyses and deterministic and probabilistic sensitivity analyses assessed the impact of uncertainty in model inputs on outcomes. Results:Over a 25-year lifetime horizon, treatment with nivolumab resulted in a gain of 0.64 quality-adjusted life-years (QALYs) versus everolimus. Nivolumab had greater total costs versus everolimus ($US197,089 vs. $US163,902), mainly due to higher acquisition costs. The incremental cost-utility ratio (ICUR), a measure of incremental costs divided by incremental QALYs, was $US51,714 per QALY gained for nivolumab versus everolimus, and an incremental cost-effectiveness ratio was $US44,576 per life-year gained for nivolumab versus everolimus. In sensitivity analyses, average body weight had the greatest impact on the ICUR for nivolumab versus everolimus (base case $US51,714; range $US8863-$US94,566). At a $US150,000 willingness-to-pay (WTP) threshold, nivolumab had a 91.7% probability of being cost-effective versus everolimus. Conclusions:In the United States, at a WTP threshold of $US150,000 per QALY, nivolumab was found to be cost-effective. Key drivers of cost-effectiveness were survival inputs for OS and the average weight of patients; the latter directly affects nivolumab drug acquisition cost.