Abstract
Background/Aims: Upadacitinib, a selective Janus kinase 1 inhibitor, has demonstrated efficacy in clinical trials for inflammatory bowel disease (IBD); however, real-world data from Asian populations remain limited. Methods: We conducted a singlecenter retrospective study to evaluate the real-world effectiveness and safety of upadacitinib in Korean patients with ulcerative colitis (UC) or Crohn’s disease (CD). Adult patients who initiated upadacitinib between July 2021 and November 2024 were included. Symptom-based clinical activity was assessed using patient-reported outcomes at baseline and 6 months. Adverse events and surgical interventions were also documented. Results: Forty patients (28 CD, 12 UC) were analyzed. At 6 months, symptom-based clinical remission was achieved in 82.4% of CD and 81.8% of UC patients, with clinical response rates of 88.2% and 90.9%, respectively. No clinical or treatment-related factors were significantly associated with remission in univariate analyses. Adverse events occurred in 57.5% of patients, all grade 1, and no treatment discontinuations were required. Six patients with CD required surgery during treatment. Conclusions: Upadacitinib was effective and well tolerated over 6 months in Korean patients with moderate-to-severe IBD, including those with biologic-experienced patients. These findings support its use in routine clinical practice, while highlighting the need for prospective studies to confirm its long-term safety and efficacy in Asian populations.