OBJECTIVES: Ankylosing spondylitis (AS) is an inflammatory disease of unknown cause. The study evaluated the cost effectiveness of adalimumab vs. placebo, golimumab vs. placebo, and adalimumab vs. golimumab in patients with active AS from the Italian payer perspective. METHODS: A cohort Markov model was developed to estimate over a time horizon of 40 years costs and QALYs associated with adalimumab or golimumab, when used according to existing treatment guidelines. The analysis was based on data from two Phase III studies of adalimumab and golimumab in active AS (combined ATLAS and Canadian trials, and GO-RAISE, respectively). Using the trial information, patients were categorized into responders and non-responders at week 12. In the base case model,  response was defined using the ASAS 20 criterion. A univariate and probabilistic sensitivity analyses was performed to assess the robustness of the results. RESULTS: In the base case adalimumab therapy estimate 1.29 more discounted QALYs per patient vs. conventional therapy anda total net cost (adalimumab vs. placebo) of € 43,617 per patient resulting in an ICER of € 33,704/QALY. The analysis performed between golimumab vs placebo led to ICER of € 39,149 per QALY gained. Comparing adalimumab to golimumab, adalimumab resulted in 0.12 additional QALYs and € 2,350 in savings and is therefore considered dominant.   These results were sensitive to whether the proportion of responders were adjusted for age or non-response imputation between trials and the proportion of patients who weighed over 100 kg and would therefore require a higher dose of golimumab to reach similar effectiveness. The results further favored adalimumab when indirect costs were included. CONCLUSIONS: From the Italian payer and societal (in sensitivity analysis) perspectives, treatment of  AS with adalimumab is cost saving and more effective compared to golimumab, and thus is dominant versus golimumab, when used according to the general treatment guidelines.