P0673 Proactive switching to subcutaneous vedolizumab in Inflammatory bowel disease correlates with raised trough levels and confers a clinical benefit: a real-world experience

Field: Medicine (Health Sciences)

Abstract Background Vedolizumab is a gut-selective monoclonal antibody that is well-recognised for managing moderate and severe Crohn’s disease (CD) and Ulcerative Colitis (UC) [1]. Subcutaneous (SC) vedolizumab has been shown to be an effective and well-tolerated alternative to the intravenous (IV) form [2,3]. However, there remains a lack of data on real-world outcomes. This study evaluates the effectiveness and safety outcomes of switching from IV to SC vedolizumab in CD and UC. Methods We collected retrospective data from the electronic patient records at West Middlesex Hospital for all adults currently receiving vedolizumab for CD and UC between December 2017 and September 2024. This included patients’ demographics, disease epidemiology, current and previous biologic treatment, vedolizumab serum concentrations, and faecal calprotectin (FCP) levels. The primary endpoints were FCP and serum vedolizumab levels pre- and post-switch. The secondary endpoints were the development of adverse events and the need for rescue therapy post-switch. Results We included 105 patients with a median age of 59. Of these, 54.28% are males (n=57). 43 patients (40.95%) were switched to maintenance SC. Most patients were on the standard 8-weekly dosing regimen of intravenous vedolizumab pre-switch (88.37%, n=38), while the rest (n=5, 11.62%) were on an escalated 4-weekly regimen. More than half (n=23, 53.48%) of the patients were switched on a clinical basis, while the remainder (n=20, 46.51%) were switched due to patient preference. All the patients in the former group had low vedolizumab levels (&lt; 15 mg/dl), and almost half (n=11) had associated active disease. In the low-level group switched to SC, UC constituted 52.17% (n=12) and CD was 47.82% (n=11). Ten patients (43.47%) had previously received anti-TNF-alpha. The median (IQR = Q3-Q1) pre-switch vedolizumab serum concentration level was 10 (5.5) mg/L, which almost tripled to 29.3 (15.6) mg/L after switching (12 to 52 weeks post-switch). The median faecal calprotectin (FCP) levels dropped from 357 (820) µg/g to 259 (493.5) µg/g post-switching to SC. The patients who remained on IV had a median vedolizumab level of 14.6 (11) mg/L and FCP of 263.5 (653.5) µg/g. None of the patients who were switched because of low levels sustained adverse effects compared to 5 patients (8.06%) in the IV group (mucocutaneous (n=2), joint (n=1) and fatigue (n=1) symptoms). Over the one-year follow-up period, one patient (4.34%) required rescue steroid therapy, compared to three (4.83%) in the IV group. Conclusion Implementing proactive subcutaneous switching of vedolizumab in a real-world setting correlates with higher levels confers improved clinical response, and has a good safety profile, reflecting clinical trial results. References 1.Raine T, Bonovas S, Burisch J, et al. ECCO Guidelines on Therapeutics in Ulcerative Colitis: Medical Treatment. J Crohns Colitis. 2022;16:2–17. doi: 10.1093/ecco-jcc/jjab1782 2.Lim SH, Gros B, Sharma E, et al. Safety, Effectiveness, and Treatment Persistence of Subcutaneous Vedolizumab in IBD: A Multicenter Study From the United Kingdom. Inflamm Bowel Dis. 2024;30:1284–94. doi: 10.1093/ibd/izad1663 3.Bergqvist V, Holmgren J, Klintman D, et al. Real-world data on switching from intravenous to subcutaneous vedolizumab treatment in patients with inflammatory bowel disease. Aliment Pharmacol Ther. 2022;55:1389–401. doi: 10.1111/apt.16927