Abstract:Objective: To evaluate the efficacy of Iguratimod in treating refractory ankylosing spondylitis(AS). Methods: A total of 36 patients with refractory AS were randomly assigned into 2 groups: the experimental group were treated with Iguratimod at a dose of 25 mg, twice a day, the control group were treated with their present antirheumatic drugs. The primary efficacy endpoint was the percentage of patients achieving the 20% improvement in assessment in AS(ASAS 20).The secondary efficacy endpoints included the percentage of patients achieving ASAS 5/6 responses(ASAS 5/6),Bath AS disease activity index 50(BASDAI 50), the percentage of patients achieving a 50% improvement in ASAS (ASAS 50)and the ASAS partial remission.The improvement in BASDAI, Bath AS functional index(BASFI),subject global assessment,total back pain, morning stiffness time,erythrocyte sedimentation rate(ESR) and the C reactive protein (CRP) were observed regularly.All subjects in the study were evaluated for safety. Results: At week 12, the percentage of patients achieving the ASAS 20 was 44.4%, at week 20, the percentage of patients achieving the ASAS 20 was 66.7%. Furthermore,the secondary efficacy endpoints include ASAS 5/6, BASDAI 50, ASAS 50 ,ASAS partial remission were also improved.At week 24, the percentage of patients achieving the ASAS 5/6 was 61.1%, the percentage of patients achieving the BASDAI 50 was 55.6%, the percentage of patients achieving the ASAS 50 was 50% and the percentage of patients achieving the ASAS partial response was 27.8%. Conclusion: Iguratimod can effectively alleviate the refractory AS patients clinical symptoms.