PD59-05: Cost Effectiveness of adjuvant pembrolizumab after nephrectomy for RCC: insights for patient selection from a Markov Model

Vidit Sharma*, Kevin M Wymer, Daniel D Joyce, James Moriarty, Bijan J Borah, R. Houston Thompson, Brian A Costello, Bradley C Leibovich, Stephen A Boorjian, Rochester, MN

Introduction: KEYNOTE-564 found that adjuvant pembrolizumab after nephrectomy for high-risk clear cell renal cell carcinoma (RCC) decreased the risk of disease progression and overall mortality–albeit with immature follow-up (2 years).  Herein, we used a Markov-model to consider the costs, toxicities, and efficacy of pembrolizumab and investigate its utility at a population level.

Methods: A decision-analytic Markov Model was used to conduct a cost-utility analysis of adjuvant pembrolizumab versus placebo after nephrectomy for high-risk clear cell RCC, using data from KEYNOTE-564 to inform model probabilities. Utility values were extracted from the literature. Base-case analyses were conducted with 5-year and 15-year time horizons (using extrapolations from 2-year outcomes). Primary outcomes were Quality-adjusted life years (QALYs), 2021 US Medicare costs, and Incremental cost-effectiveness ratios (ICERs) evaluated with a willingness-to-pay threshold of $100,000/QALY. One-way sensitivity analyses and probabilistic sensitivity analyses with 100,000 Monte-Carlo simulations were performed on model conclusions.

Results: Pembrolizumab had higher QALYs and costs relative to placebo (Table). Pembrolizumab was not cost-effective at a 5-year time horizon but did become cost-effective at 15 years. On one-way sensitivity analysis, pembrolizumab became cost-effective at 5-years if: 1) its cost was less than $5,064 (base = $10,278) or 2) if the 5-year risk of progression was 18.8% higher in placebo vs pembrolizumab (base = 9%). Using pembrolizumab’s reported hazard ratio of 0.68 for progression from KEYNOTE-564, we estimated that pembrolizumab would be cost-effective at 5-years for all patients with a Mayo Progression Free Survival Score of 10 or higher. Probabilistic sensitivity analysis found that pembrolizumab was cost-effective for 29% and 58% of microsimulations at 5 and 15 years, respectively.

Conclusions: At current prices, adjuvant pembrolizumab was not cost-effective for all trial patients at a population level at 5-years after treatment, though it did emerge to be cost-effective at 15 years. At 5-years, adjuvant pembrolizumab was found to be cost-effective only for the highest risk subsets of RCC. Longer term trial data of progression-free survival and overall survival are necessary to confirm these extrapolations.

Source of Funding: None