Jansson, Johan

Abstract Background Vedolizumab (VDZ) is a gut-selective α 4β 7 integrin monoclonal antibody approved for IV administration for moderate to severe ulcerative colitis (UC). The phase 3 VISIBLE 1 study evaluated SC VDZ for UC maintenance therapy. After 2 IV doses, 56.1% patients had a clinical response at week 6; among patients who received a third induction infusion, clinical response rates were 79.7%. In this post hoc analysis, we examined baseline characteristics as predictors of clinical response to IV induction with VDZ. Methods In the VISIBLE 1 study (NCT02611830; EudraCT 2015-000480-14), patients (patients) received IV VDZ 300 mg at Weeks 0 and 2. At Week 6, clinical responders were randomised to maintenance SC therapy; nonresponders were given a third IV dose and reassessed at Week 14. As endoscopy was only available at Week 6, the clinical response at Week 6 was defined as ≥3 points and ≥30% reduction in complete Mayo score from Week 0 and at Week 14 as a ≥2 points and ≥25% reduction in partial Mayo score from Week 0. Both definitions also included an accompanying decrease in rectal bleeding subscore ≥1 or absolute subscore ≤1. Results Overall, 383 patients received ≥1 dose of IV VDZ. Of these, 56.1% responded at Week 6 after 2 VDZ doses. Of the 143 patients who received 3 IV doses, 79.7% responded at Week 14. No clinically meaningful differences in baseline demographic and disease characteristics were observed between patients who responded after 2 or 3 IV doses (Table). Differences in disease location and partial Mayo score (< or ≥6) were observed between the responders and nonresponders in the 3 IV dose group. Baseline characteristics were evaluated descriptively to assess predictors of clinical response after 2 or 3 IV VDZ doses. Conclusion Clinical response was achieved by most patients after either 2 or 3 IV VDZ infusions in the VISIBLE 1 trial. Post hoc analyses revealed no clinically meaningful differences in baseline characteristics or disease characteristics that could serve as predictors of response following 2 or 3 VDZ infusions. Further real-world experience may elucidate potential predictors of response to VDZ.