OBJECTIVES : The KEYNOTE-181 study has demonstrated the prolonged survival benefits of pembrolizumab compared with chemotherapy as the second-line treatment among Chinese patients with ESCC. This study aimed to assess the cost-effectiveness of pembrolizumab versus chemotherapy among Chinese patients with advanced ESCC who failed the first-line treatment.

METHODS : We developed a Markov model to simulate the progression of ESCC through three health status (progression-free survival, survival with progressed disease, and death). Time-varying transitional probabilities were estimated using patient-level data from the KEYNOTE-181 study. Utility and direct medical costs in China, measured in US dollars(USD), were obtained from published literature. Costs were standardized to the 2020 value using the consumer price index for medical supply. The simulation was conducted using a life-time window with a 3% annual discount rate for cost and utility. The model estimated the incremental cost-effectiveness ratio(ICER) of pembrolizumab versus chemotherapy from a health system perspective. We performed one-way sensitivity analyses to assess the robustness of the results, and a subgroup analysis using survival data from the Chinese cohort of the KEYNOTE-181 study exclusively.

RESULTS : The incremental effectiveness and cost of pembrolizumab versus chemotherapy were 0.09 QALY and 37,082USD, resulting in an ICER of 390,509USD/QALY. We found the uncertainties in progressed disease utility had the biggest impact on the cost-effectiveness of pembrolizumab. When survival data from Chinese-only cohort was used, the incremental effectiveness and cost of pembrolizumab versus chemotherapy were estimated to be 0.44 QALY and 43,047USD, resulting in an ICER of 97,229USD/QALY.

CONCLUSIONS : Based on a willingness-to-pay threshold of 25,841USD (three times GDP) commonly used in China, pembrolizumab is currently not a cost-effective option for Chinese patients with ESCC compared with chemotherapy.