Vedolizumab (VDZ), a gut-selective antibody that binds specifically to integrin α4β7, is approved for treatment of adults with moderate-to-severe ulcerative colitis (UC). An association between VDZ levels and clinical remission during induction therapy at Week (Wk) 6 was observed in pivotal trial data; the majority of nonresponders at Wk 6 had VDZ levels <40 μg/mL, and those with VDZ clearance >0.14 L/d had reduced efficacy outcomes (Osterman MT, et al. Aliment Pharmacol Ther. 2019). In the ongoing randomized controlled trial (ENTERPRET), we are evaluating whether dose escalation starting at Wk 6 in clinical nonresponders with high VDZ clearance (level <50 μg/mL) at Wk 5 leads to improved outcomes at Wk 30.