Filgotinib Is an Effective and Safe Treatment Option for Difficult-To-Treat Ulcerative Colitis: Real-World Evidence of the Dutch Initiative on Crohn and Colitis (ICC) Registry

Background: Filgotinib is a preferential Janus kinase 1 (JAK-1) inhibitor registered for the treatment of ulcerative colitis (UC). Real-world effectiveness of filgotinib, especially for difficult-to-treat (DTT, failure of ≥ 2 prior advanced therapies) patients, has been scarcely reported. Objective: This study aimed to assess the effectiveness and safety of filgotinib for UC patients in routine care. Methods: The Dutch ICC registry enrolled UC patients initiating filgotinib and prospectively evaluated outcomes up to 52 weeks. The primary outcome was corticosteroid-free clinical remission (CSFR, Simple Clinical Colitis Activity Index [SCCAI] ≤ 2 without steroid use) at week 52. Secondary outcomes included clinical remission (SCCAI ≤ 2), biochemical remission (C-reactive protein serum concentration < 5 mg/L and/or faecal calprotectin level < 250 μg/g), treatment persistence and safety. Results: A total of 96 UC patients were included. At 52 weeks, 39.5% (34/76) of patients with disease activity at baseline were in CSFR. Out of the patients that met the criteria for DTT disease (n = 68; 71%), 36.4% achieved CSFR. Treatment persistence at 52 weeks was 71.4% (CI 56.5–90.3) and 53.4% (CI 42.6–67.0) for non-DTT and DTT patients, respectively. The main reasons for discontinuation of filgotinib were primary non-response (n = 21, 54%) or secondary loss of response (n = 8, 23%). No severe infections were documented. Most reported adverse events included headache (n = 5), nausea (n = 3) and hypercholesterolemia (n = 3). Conclusion: Filgotinib is an effective and well-tolerated treatment option for UC, including DTT disease. No new safety signals were found.