Sintilimab is an IgG4 anti-programmed cell death protein 1 (PD-1) antibody that has a high-affinity blocking interaction with PD-1 and its ligands. The updated ORIENT-11 study showed that sintilimab plus chemotherapy significantly prolonged progression-free and overall survival, compared with chemotherapy alone, in the first-line treatment of non-squamous non-small cell lung cancer (NSCLC). In China, it is uncertain whether sintilimab is a cost-effective alternative to standard immunotherapy.

A partitioned survival model with three health states (including progression-free survival, disease progression, and death) was constructed from the Chinese societal perspective using a three-week cycle with a lifetime horizon (16 years). Individual patient data were captured from the updated ORIENT-11 study, and high-risk and clinically severe adverse events were specifically added to the states. Quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs) were the primary outcomes. Costs, health productivity losses, and utilities were derived from questionnaires and supplemented by expert opinion and literature review. All costs were expressed in 2021 USD, and costs and QALYs were discounted at an annual rate of five percent. Sensitivity analyses and scenario analyses considering the healthcare system perspective were performed to explore model uncertainty.

Patients receiving sintilimab plus chemotherapy incurred a mean total cost of USD67,727 and gained 2.5 QALYs during the lifetime period, compared with USD40,530 and 1.5 QALYs for patients receiving standard chemotherapy. The corresponding ICER was USD27,665 per QALY in China. At a willingness-to-pay threshold of three times the gross domestic product per capita in China (USD37,663), sintilimab plus chemotherapy was the optimal treatment in 84 percent of replications. Deterministic sensitivity analysis showed that the most significant driving determinant was the discount rate of costs and QALYs. An ICER of USD21,020 per QALY was obtained from the Chinese healthcare system, validating the robustness of the cost-effectiveness analysis.

Compared with standard chemotherapy, sintilimab plus chemotherapy is a cost-effective treatment regimen for non-squamous NSCLC in China. Thus, sintilimab may benefit Chinese patients and should be promoted by decision makers.