The 6-week Induction Phase contained 2 cohorts of participants: Cohort 1 participants were randomized and treated with double-blind study drug, and Cohort 2 participants were treated with open-label vedolizumab. The second cohort was enrolled to ensure that the sample size of Induction Phase responders randomized into the Maintenance Study provided sufficient power for the Maintenance Study primary efficacy analysis. These participants did not contribute to the efficacy analyses performed for the Induction Study. Participants in both cohorts were assessed for treatment response at Week 6.