Cadonilimab plus chemotherapy for patients with HER2-negative advanced gastric or gastroesophageal junction adenocarcinoma in China and the United States: a cost-effectiveness analysis.

[BACKGROUND] The COMPASSION-15 trial showed that cadonilimab plus chemotherapy has significant clinical advantages in patients with HER2-negative advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma compared to chemotherapy. This study evaluated the cost-effectiveness for patients in China and the United States.

[OBJECTIVE] To provide advice for patients on the use of cadonilimab.

[DESIGN] The cost-effectiveness analysis.

[METHODS] A partitioned survival model was conducted from perspective of the Chinese and U.S. healthcare systems over a lifetime horizon. Key parameters of the model were derived from COMPASSION-15 trial and published literature. In this study, costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) were taken as main outcomes. Sensitivity analyses, price simulations, and programmed death ligand 1 combined positive score (PD-L1 CPS) subgroup analyses were conducted to test robustness.

[RESULTS] In base-case analysis, cadonilimab plus chemotherapy group achieved an ICER of US dollars (USD) 32,630.84/QALY in China and USD 109,996.43/QALY in the United States, falling within the established willingness to pay (WTP) thresholds in both cases. At the current negotiated Chinese price (USD 208.94/100 mg), cadonilimab was cost-effective; in the United States, it remained cost-effective when priced below USD 437.87 (USD 100,000/QALY threshold) or USD 870.23 (USD 150,000/QALY threshold) per 100 mg. Subgroup analyses demonstrated that patients with PD-L1 CPS ⩾5 had 100% (China) and >94% (U.S.) probability of cost-effectiveness, whereas those with CPS <5 had reduced economic favorability. Sensitivity analyses identified progression-free survival utility, drug price, and body weight as key drivers of ICERs.

[CONCLUSION] As a first-line strategy for patients with HER2-negative advanced G/GEJ adenocarcinoma, cadonilimab combined with chemotherapy represents a cost-effective option in both China and the United States. Its economic advantage is most pronounced in patients with high PD-L1 expression and at lower drug prices. These findings provide quantitative evidence supporting reimbursement negotiations and future pricing strategies for cadonilimab in global markets.