OBJECTIVES: This study evaluates the economics of seven biologics marketed in China compared with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) in the treatment of biologic-naive patients with Ankylosing Spondylitis (AS) based on the perspective of the Chinese health system.

METHODS: This study adopted York model, with 1 year as a recurring cycle and a lifetime timeframe for the study. The control group was csDMARDs, while the comparators were seven biologics approved in China for AS indications. Four TNFi inhibitors, two IL-17 inhibitors and one JAK inhibitor were included. Clinical parameters adopted treatment response, short-term disease activity and patient functioning, as well as long-term structural disease progression. Utilities are dependent on indicators such as BASDAI, BASFI, gender and age. Drug prices were analyzed using the median price of the Chinese market in the baseline analysis, and the prices of brand-new drugs（highest price）and lowest prices were used in the scenario analysis. Costs and outcomes were discounted at 5.0%. 2023 GDP per capita (¥85698/QALY）in China was set as the threshold.

RESULTS: Compared with csDMARDs, the ICER of Golimumab was ¥104217.4/QALY , which is between 1-3 times of GDP per capita while the ICER of other six biologics were less than ¥85698/QALY. After comparing the economics of biologics, two IL-17 inhibitors (Secukinumab and Ixekizumab) ranked first, followed by Tofacitinib as JAK inhibitor and four TNFi inhibitors (Infliximab, Etanercept, Adalimumab and Golimumab) orderly. In the scenario analysis , IL-17 inhibitors were still the most economical intervention while using the lowest price (for generics) or the highest price(for original drugs).

CONCLUSIONS: Biologics are cost-effectiveness selection for AS treatment. Overall, Secukinumab had the most cost-effective advantage, followed by Ixekizumab, which were both IL-17 inhibitors. Different pricing of a biologic by different manufacturers can greatly affect the economics.