OBJECTIVES: Pembrolizumab was recently approved in China as the first anti-PD1 therapy for patients with previously advanced melanoma treated. The aim of this study is to evaluate the cost-effectiveness of pembrolizumab compared to standard-of-care therapy in patients with unresectable or metastatic melanoma after one line of therapy in China.

METHODS: A partitioned-survival model was developed to compare the costs and health benefits of pembrolizumab versus chemotherapy（Paclitaxel+ Carboplatin) for patients with previously treated unresectable or metastatic melanoma in China. A combination of clinical trial data (from patients previously treated, randomized to pembrolizumab in the randomized phase 3 study KEYNOTE-006), published literature, and results from a network meta-analysis, were used to derive the time in Progression Free Survival, Overall Survival, and post-progression survival for pembrolizumab and chemotherapy, the incidence of adverse events and utilities by health state (considering Chinese utility values and a time-to-death approach). A lifetime horizon (20 years) from the Chinese Healthcare Service perspective were considered, applying a 5% discount rate. A panel of Chinese clinical experts derived health state resource use and chemotherapy-related adverse events to estimate Chinese-specific disease management costs. Deterministic and probabilistic sensitivity analyses were conducted to test for the robustness of the results.

RESULTS: Pembrolizumab increases life expectancy by 2.63 life-years (LYs) and 2.26 quality-adjusted life-years (QALY), with increased costs of ¥397,788 compared to chemotherapy. The estimated incremental cost-effectiveness ratio is ¥176,187 per QALY, and ¥151,470 per LY. Results are most sensitive to utilities for long-term survivors and variations in survival projections. The probability of pembrolizumab being cost effective versus chemotherapy is 84% at a willingness-to-pay threshold of ¥195,000/QALY (i.e. 3 times the Chinese GDP).

CONCLUSIONS: Pembrolizumab is cost-effective compared to chemotherapy for the treatment of previously-treated unresectable or metastatic melanoma patients in China.