Cost-effectiveness of disitamab vedotin plus toripalimab in HER2-expressing advanced urothelial carcinoma in China.

BACKGROUND: Combination therapy with disitamab vedotin (DV) and toripalimab has been proven to significantly prolong progression-free survival (PFS) and overall survival (OS) first-line in patients with human epidermal growth factor receptor 2 (HER2) expressing, locally advanced or metastatic urothelial carcinoma (UC). The economic viability of this treatment strategy remains unclear. This study systematically evaluated the cost-effectiveness of DV plus toripalimab therapy versus platinum-based chemotherapy for these patients from the perspective of the Chinese healthcare system. METHODS: Based on data from the RC48-C016 clinical trial, a Markov model was established to conduct a cost-effectiveness analysis of DV plus toripalimab versus platinum-based chemotherapy in patients with advanced or metastatic UC. Cost parameters were estimated by referencing published literature or local pricing models, while utility parameters were derived from published literature. The total cost, quality-adjusted life years (QALYs) for each group, and the incremental cost-effectiveness ratio (ICER) were calculated. The ICER was compared with China's willingness-to-pay (WTP) threshold to evaluate the economic efficiency of the two treatment strategies. Additionally, sensitivity analysis and scenario analysis were performed to verify the robustness of the established Markov model. RESULTS: Patients in the chemotherapy group incurred a total cost of $59,329 with a corresponding gain of 1.78 QALYs. In comparison, patients in the DV plus toripalimab group had an incremental cost of $64,361 and an incremental QALY gain of 0.74, yielding an ICER of $86,954 per QALY. This value exceeded China's WTP threshold of $40,977 per QALY. Results of sensitivity and scenario analyses indicated that the cost of DV was the most influential factor on the ICER, and the model outputs were robust. For the combination therapy to be cost-effective, a 60% price reduction for both DV and toripalimab, or a 77% price reduction for DV alone, would be required. CONCLUSION: DV in combination with toripalimab is not cost-effective compared with platinum-based chemotherapy first-line in the treatment of patients with HER2-expressing locally advanced or metastatic UC in China.