Base-case analysis results.

Background
This study aims to compare the cost-effectiveness of sintilimab in combination with chemotherapy, with or without bevacizumab biosimilar IBI305, versus chemotherapy alone for patients with epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC) who have progressed on tyrosine-kinase inhibitor (TKI) treatment from the perspective of the Chinese healthcare system.
Methods
10-year Markov model was developed using a 21-day cycle length. Transition probabilities were derived from the ORIENT-31 trial, while cost and health state utilities were obtained from publicly databases, local hospitals, and published literature. Incremental cost-effectiveness ratios (ICERs) were calculated as the primary model output and compared to a willingness-to-pay (WTP) threshold range of $15,289.34 to $38,223.34 per quality-adjusted life-years (QALY). Sensitivity analyses were performed to assess the robustness of the model.
Results
In the base-case analysis, sintilimab plus IBI305 and chemotherapy had an ICER of $53,266.32/QALYs, exceeding the upper WTP threshold. Sintilimab plus chemotherapy had an ICER of $15,329.11/QALY, slightly above the lower WTP threshold. Subgroup analysis yielded consistent results. Deterministic sensitivity analyses found no ICER for sintilimab plus chemotherapy beyond the upper WTP threshold. Most model input changes did not decrease the ICER of sintilimab plus IBI305 and chemotherapy below the upper WTP threshold. Probabilistic sensitivity analyses further demonstrated the cost-effectiveness superiority of sintilimab plus chemotherapy over sintilimab plus IBI305 and chemotherapy.
Conclusion
This study supports the cost-effectiveness of using sintilimab in combination with chemotherapy. Nevertheless, the cost-effectiveness of combining sintilimab with IBI305 and chemotherapy in this particular patient group may be lacking.