Efficacy and safety of Janus kinase inhibitors in Behçet's disease: A systematic literature review.
INTRODUCTION: Behçet's disease e (BD) is a chronic, relapsing, multisystem inflammatory disorder that if not successfully treated can lead to severe, organ or life-threatening complications. Despite treatment with glucocorticoids, immunosuppressants, and tumor necrosis factor (TNF) inhibitors, some patients still have refractory disease that mandates additional therapeutic options. The pathogenesis of BD involves dysregulated innate and adaptive immune responses with multiple cytokines signaling through the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway. By targeting multiple inflammatory pathways, JAK inhibitors have emerged as a promising therapeutic option. However, current evidence remains limited and heterogeneous. Therefore, we conducted this systematic review to evaluate their efficacy and safety in BD. METHODS: We conducted a systematic literature review in accordance with PRISMA 2020 guidelines (PROSPERO registration: CRD420261381955). PubMed/MEDLINE, Embase, Scopus, and Web of Science were searched from inception to March 2026. Original clinical studies evaluating Janus kinase (JAK) inhibitors in BD were included. Two reviewers independently performed study selection, data extraction, and quality assessment using Joanna Briggs Institute tools. Due to heterogeneity, results were synthesized narratively, focusing on efficacy and safety outcomes. RESULTS: Seventeen studies (99 patients) were included, predominantly case reports and small observational cohorts with overall high methodological quality. All evaluated tofacitinib, baricitinib, or upadacitinib, with no data on other JAK inhibitors. Patients were highly treatment-refractory, with prior failure of conventional and biologic therapies. Upadacitinib was the most frequently studied agent and demonstrated an overall response rate of 85.2% and complete remission in 59.3% in a multi-center study. Efficacy was observed across multiple domains, with the most consistent responses in intestinal disease, including clinical and endoscopic remission, alongside frequent glucocorticoid-sparing effects. Safety findings were consistent with known JAK inhibitor safety profiles, with mainly mild to moderate infections and manageable laboratory abnormalities, and no clear signal for increased thrombotic events, although follow-up was limited. CONCLUSION: JAK inhibitors demonstrate promising efficacy in BD, particularly in refractory and multisystem disease. The most consistent evidence of efficacy was observed in gastrointestinal involvement, whereas data for other disease domains remain limited. Their safety profile appears consistent with existing data, although further follow up and validation is required. High-quality randomized controlled studies are an imminent need to study the potential role of JAK inhibitors in BD.