Efficacy, Safety and Immunogenicity of the Proposed Biosimilar Vedolizumab PB016 in Comparison With Entyvio®

This is a multi-center, randomized, parallel arm, double-blind study with a total duration of 54 weeks. Approximately 750 participants with moderately to severely active Colitis Ulcerosa will be randomized to receive up to eight doses of either PB016 or Entyvio®. The study will be conducted at up to 200 study centers, located in approximately 18 countries worldwide. The clinical trial is designed to compare the efficacy, safety, and immunogenicity of 300 mg IV PB016 versus Entyvio® in patients with moderately to severely active UC. The active period of Study PB016-03-01 comprises the following: * Stage 1: Induction Period - after 1:1 randomization, intravenous infusions of either PB016 or Entyvio® at a dose of 300 mg at Weeks 0 and 2. * Stage 2: Maintenance Period - further doses at Weeks 6, 14, 22, 30, 38, and 46. * Stage 3: Follow-up Period - At Week 54, a safety follow-up call will be conducted.