Targeted therapies and conventional care for the treatment of ankylosing spondylitis in China: a cost-effectiveness analysis based on the network-meta analysis

Objective: This study aimed to evaluate the long-term cost-effectiveness of conventional care (CC) and seven first-line targeted therapies marketed in China for the treatment of patients with ankylosing spondylitis (AS)–namely secukinumab, ixekizumab, infliximab, etanercept, adalimumab and golimumab and tofacitinib–from the perspective of the Chinese health care system. Methods: The York model was structured as a 12-week decision tree leading into two Markov models. This study set 1 year as a recurring cycle and a lifetime timeframe for the model. Primary model outcomes included the costs in Chinese yuan (CNY), health outcomes in quality-adjusted life-years (QALYs) and the incremental cost-effectiveness ratio (ICER) under a willingness-to-pay threshold of ¥89,358 (equal to the per capita gross domestic product in China in 2023) per QALY. Parameters in the York model were captured from network meta-analyses and literature including treatment response, short-term disease progression, patient functioning and long-term structural disease progression. Utilities are dependent on indicators such as the BASDAI score, the BASFI score, gender and age. Drug prices were analysed using the median price of the Chinese market from YAOZH net in the basic analysis. Costs and outcomes were discounted at 5.0%. We performed deterministic and probabilistic sensitivity analyses to investigate the robustness of the results. The prices of original drugs and generic drugs were used in the scenario analysis. Results: Compared with CC, the ICER of golimumab was ¥104,217.4/QALY, which is between 1 and 3 times the GDP per capita, while the ICERs of the other six targeted therapies were less than ¥89,358/QALY. The specific economic rank of the targeted therapy was as follows: secukinumab > ixekizumab > tofacitinib > infliximab > etanercept > adalimumab > golimumab. Treatment response rates such as the BASDAI50, changes in the BASDAI/BASFI scores and the discounting rate were key model drivers. According to the scenario analysis, IL-17 inhibitors were still the most economical intervention when original drugs and generic drugs were used. Conclusion: Targeted therapies are cost-effective treatments for AS. Overall, IL-17 inhibitors were the dominant treatment. The choice of the brand-new prices or generic drug prices can greatly affect economics.