Cost-effectiveness of sugemalimab plus chemotherapy versus placebo plus chemotherapy as first-line treatment for advanced oesophageal squamous cell carcinoma in China

OBJECTIVE: Sugemalimab plus chemotherapy significantly prolonged progression-free survival and overall survival in patients with advanced oesophageal squamous-cell carcinoma (ESCC). However, considering the high cost of sugemalimab, we evaluated the cost-effectiveness of sugemalimab plus chemotherapy in the first-line treatment for advanced ESCC. DESIGN: A partitioned survival model with a 3-week cycle length and the lifetime time horizon was constructed to assess the cost-effectiveness of sugemalimab plus chemotherapy versus placebo plus chemotherapy as first-line treatment for advanced ESCC. The key survival data, drug costs, and utility values were obtained from the GEMSTONE-304 trial, YAOZHI database and the published literature. Total costs, quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were measured. One-way and probabilistic sensitivity analyses were performed to evaluate the uncertainty and model stability. In addition, subgroup and scenario analyses were conducted. SETTING: The Chinese healthcare system perspective. PARTICIPANTS: A hypothetical Chinese cohort of patients with unresectable, locally advanced, recurrent or metastatic ESCC. INTERVENTIONS: Sugemalimab plus chemotherapy versus chemotherapy. PRIMARY OUTCOME MEASURE: Costs, QALYs, ICERs. RESULTS: Compared with the placebo plus chemotherapy, the sugemalimab plus chemotherapy provided an additional 0.36 QALYs, with an incremental cost of $44 376.88. The result of ICER was $119 400.69/QALY, which was significantly higher than the willingness-to-pay (WTP) threshold of three times per capita gross domestic product ($38 024.68/QALY) in 2023. Sensitivity analysis revealed that the cost of sugemalimab, the discount rate and the utility values were the most influential parameters on the base-case analysis results. Subgroup analyses showed that programmed cell death - ligand 1 subgroup ICERs exhibited dose-dependent efficacy: the ICERs for sugemalimab plus chemotherapy versus placebo plus chemotherapy were $138 739.23/QALY and $108 051.81/QALY in advanced ESCC patients with 1 ≤ combined positive score (CPS)