The purpose of this study is to investigate the efficacy and safety of vedolizumab intravenous (IV) dose optimization on mucosal healing compared with the standard vedolizumab IV dosing regimen over a 30 week treatment period in participants with moderately to severely active ulcerative colitis (UC) and high vedolizumab clearance, based on a Week 5 predefined serum vedolizumab concentration threshold less than (\<) 50 microgram per milliliter (microg/mL) and who are Week 6 non-responders based on partial Mayo score.