Real-World Experience of Switching from Intravenous to Subcutaneous Vedolizumab in Korean Patients with Inflammatory Bowel Disease.

Background/aims: Subcutaneous (SC) vedolizumab (VDZ) has recently become available for patients with inflammatory bowel disease (IBD) in Korea. This retrospective observational study aimed to evaluate the clinical outcomes and safety of switching from intravenous (IV) to SC VDZ.

Methods: Patients with IBD who switched from IV to SC VDZ between 2023 and 2024 were included. The primary outcome was the 24-week persistence rate of SC VDZ. Secondary outcomes included clinical factors associated with SC VDZ persistence, safety profiles, subsequent treatment courses after discontinuation of SC VDZ, and recapture success rate after reverting to IV VDZ.

Results: A total of 101 patients with IBD (72 with ulcerative colitis [UC] and 29 with Crohn's disease) were included. After 24 weeks, 72 patients (71.3%) maintained SC VDZ. Corticosteroid use at switching was the strongest predictor of 24-week SC VDZ failure in both the overall IBD cohort (p=0.018) and in patients with UC (p=0.027) in multivariable analyses. Kaplan-Meier analysis showed that patients with UC with intensified IV dosing intervals (p=0.021), failure to clinical remission (p=0.038), or concomitant corticosteroid use at switching (p<0.001) were more likely to discontinue SC VDZ. Injection-site reactions occurred in 24 patients (23.8%). A total of 34 patients (33.7%) discontinued SC VDZ; 19 resumed IV VDZ; and 13 initiated another advanced therapy. The recapture success rate after reverting to IV VDZ was 73.7%, with higher success in those who discontinued because of injection-site reactions or poor adherence.

Conclusions: SC VDZ persistence is significantly influenced by disease activity at the time of switching.