目的 从中国卫生系统角度出发，评价西妥昔单抗β联合FOLFIRI（伊立替康+亚叶酸钙+氟尿嘧啶）与单独FOLFIRI相比，一线治疗RAS/BRAF野生型转移性结直肠癌的成本－效果，为临床决策和医保政策制定提供经济证据。方法 基于西妥昔单抗β联合FOLFIRI的Ⅲ期临床试验，构建马尔可夫模型，模拟周期为2周，模拟时间范围为10年。以总成本、质量调整生命年（QALYs）为输出指标，计算增量成本效果比（ICER）；通过单因素敏感性分析、概率敏感性分析及情景分析验证模型稳健性。成本数据以2024年人均GDP9.57万元/人计算，成本与效用贴现率均为5%。结果 基本分析显示，西妥昔单抗β+FOLFIRI组总成本为162,791元，累计获得1.08QALYs；单独FOLFIRI组总成本为47,846元，累计获得0.91QALYs。与单独FOLFIRI相比，联合治疗组增量成本为114,945元，增量QALYs为0.17，ICER为676,147元/QALY，高于2024年中国人均GDP的3倍。敏感性分析显示，情景分析和敏感性分析显示了模型的稳健性。在99.9%的模拟中，西妥昔单抗β联合FOLFIRI组获得每一个QALY的增量成本高于287100元。结论 在中国人均GDP三倍的阈值下，西妥昔单抗β联合FOLFIRI一线治疗中国RAS/BRAF野生型mCRC患者，相比单独FOLFIRI不具有成本效果性。

Objective From the perspective of China's health system, to evaluate the cost-effectiveness of cetuximab β combined with FOLFIRI (irinotecan + calcium folinate + fluorouracil) compared to single-agent FOLFIRI as first-line treatment for RAS/BRAF wild-type metastatic colorectal cancer, providing economic evidence for clinical decision-making and medical insurance policy formulation. Method Based on a phase III clinical trial of cetuximab β combined with FOLFIRI, a three-state Markov model was constructed. The simulation cycle is 2 weeks (matching the FOLFIRI dosing regimen), and the simulation time range is 10 years (ensuring that 99% of cohort patients reach the death state). Output indicators include total cost and Quality-Adjusted Life Years (QALYs), to calculate the Incremental Cost Effectiveness Ratio (ICER); model robustness is verified through univariate sensitivity analysis, probabilistic sensitivity analysis, and scenario analysis. Cost data is calculated based on the per capita GDP in 2024 at 95,700 yuan/person, with both cost and utility discount rates set at 5%. Results The basic analysis showed that the total cost of the cetuximab β + FOLFIRI group was 162,791 yuan, with a cumulative gain of 1.08 QALYs; the total cost of the FOLFIRI group alone was 47,846 yuan, with a cumulative gain of 0.91 QALYs. Compared to the FOLFIRI group alone, the incremental cost of the combination therapy group was 114,945 yuan, and the incremental QALYs were 0.17, with an ICER of 676,147 yuan/QALY, which is higher than three times the per capita GDP of China in 2024. Sensitivity analysis showed that scenario analysis and sensitivity analysis demonstrated the robustness of the model. In 99.9% of simulations, the incremental cost for each QALY gained by the cetuximab β combined with FOLFIRI group was above 287,100 yuan. Conclusion At a threshold of three times the per capita GDP in China, cetuximab β combined with FOLFIRI as first-line treatment for RAS/BRAF wild-type mCRC patients in China is not cost-effective compared to FOLFIRI alone.