Janus kinase inhibitors for treating active ankylosing spondylitis: a meta-analysis of randomized controlled trials

Objective In this study, we aimed to assess the safety and efficacy of Janus kinase (JAK) inhibitors in patients with ankylosing spondylitis (AS). Methods We conducted a Bayesian network meta-analysis using direct and indirect data from randomized controlled trials (RCTs), and examined the safety and efficacy of JAK inhibitors in active AS patients exhibiting inadequate response or intolerance to two or more non-steroidal anti-inflammatory drugs (NSAIDs). Results RCTs included a total of 406 patients (203 experimental subjects and 203 controls) from three studies on upadacitinib, filgotinib, and tofacitinib. Assessment of SpondyloArthritis International Society 20% improvement (ASAS20), ASAS40, and ASAS5/6 responses were significantly higher in the JAK inhibitor group than in the placebo group. Other efficacy outcomes, such as ASAS partial remission, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI50), Ankylosing Spondylitis Disease Activity Score (ASDAS), Spondyloarthritis Research Consortium of Canada (SPARCC) Magnetic Resonance Imaging (MRI) scores, and Bath Ankylosing Spondylitis Functional Index (BASFI) were also significantly higher in the JAK inhibitor group compared to the placebo group. The JAK inhibitors significantly improved disease activity (ASAS partial remission, BASDAI50, ASDAS), function (BASFI), and MRI outcomes (SPARCC MRI spine). However, the incidence of adverse events (AEs) and serious adverse events (SAEs), and the rate of withdrawal attributed to AEs did not differ between the JAK inhibitor and placebo groups. Conclusion JAK inhibitors were effective in active AS patients exhibiting an inadequate response or intolerance to two or more NSAIDs, without the risk of SAEs; this suggests that based on our data, studies are warranted to further investigate the use of JAK inhibitors for treating AS.