Cost-effectiveness of pembrolizumab for treatment of platinum-resistant recurrent or metastatic head and neck squamous cell carcinoma in China: an economic analysis based on a randomised, open-label, phase III trial

BACKGROUND: Pembrolizumab was recently demonstrated to have survival benefit in patients with recurrent or metastatic head and neck squamous cell carcinoma (r/mHNSCC). However, the cost-effectiveness of pembrolizumab versus chemotherapy in China remains uncertain. OBJECTIVE: This analysis aimed to describe the cost-effectiveness of pembrolizumab versus standard-of-care (SOC) therapy in r/mHNSCC in China. DESIGN: A Markov model consisting of three health states (stable, progressive and dead) was developed to compare the cost and effectiveness of pembrolizumab with SOC in platinum-resistant r/mHNSCC. Model inputs for transition probabilities and toxicity were collected from the KEYNOTE-040 trial, while health utilities were estimated from a literature review. Cost data were acquired for the payer’s perspective in China. Costs and outcomes were discounted at an annual rate of 3.0%. Sensitivity analyses were conducted to test the uncertainties surrounding model parameters. OUTCOME MEASURES: The primary outcome was incremental cost-effectiveness ratios (ICERs), which were calculated as the cost per quality-adjusted life years (QALYs). RESULTS: The total mean cost of pembrolizumab and SOC was US$45 861 and US$41 950, respectively. As for effectiveness, pembrolizumab yielded 0.31 QALYs compared with 0.25 QALYs for SOC therapy. The ICER for pembrolizumab versus SOC was US$65 186/QALY, which was higher than the willingness-to-pay threshold (WTP) of US$28 130/QALY in China. The univariate sensitivity analysis indicated that utility values for progressive state, probability from stable to progressive in the SOC group, as well as cost of pembrolizumab were the three most influential variables on ICER. The probabilistic sensitivity analysis demonstrated that standard therapy was more likely to be cost-effective compared with pembrolizumab at a WTP value of US$28 130/QALY. Results were robust across both univariate analysis and probabilistic sensitivity analysis. CONCLUSIONS: Pembrolizumab is not likely to be a cost-effective strategy compared with SOC therapy in patients with platinum-resistant r/mHNSCC in China. TRIAL REGISTRATION NUMBER: NCT02252042; Post-results.