An Efficacy and Safety Study of Vedolizumab Intravenous (IV) Compared to Adalimumab Subcutaneous (SC) in Participants With Ulcerative Colitis

Inclusion Criteria: 1. Has a diagnosis of ulcerative colitis established at least 3 months prior to screening by clinical and endoscopic evidence and corroborated by a histopathology report. 2. Has moderately to severely active ulcerative colitis as determined by a Mayo score of 6 to 12 with an endoscopic subscore greater than or equal to \>=2 within 14 days prior to the randomization. 3. Has evidence of ulcerative colitis proximal to the rectum (\>=15 centimeter \[cm\] of involved colon). 4. With extensive colitis (up to the hepatic flexure) or pancolitis of \>8 years duration or left-sided colitis of \>12 years duration must have documented evidence that a surveillance colonoscopy was performed within 12 months of the initial screening visit (may be performed during the Screening Period). 5. The participant: 1. Has had previous treatment with tumor necrosis factor- alpha (TNF-alpha) antagonists without documented clinical response to treatment (example, due to lack of response \[primary nonresponders\], loss of response, or intolerance \[secondary nonresponders\]), or 2. Has previously used a TNF-alpha antagonists (except adalimumab), and discontinued its use due to reasons other than safety, or 3. Is naïve to TNF-alpha antagonist therapy but is failing current treatment (example, corticosteroids, 5-aminosalicylate \[5-ASA\], or immunomodulators). Exclusion Criteria: 1. Clinical evidence of abdominal abscess or toxic megacolon at Screening. 2. Has had an extensive colonic resection, subtotal or total colectomy. 3. Has had ileostomy, colostomy, or known fixed symptomatic stenosis of the intestine. 4. Has a diagnosis of Crohn's colitis or indeterminate colitis, ischemic colitis, radiation colitis, diverticular disease associated with colitis, or microscopic colitis. 5. Has received any of the following for the treatment of underlying disease within 30 days of randomization: 1. Non-biologic therapies (example, cyclosporine, tacrolimus, thalidomide) other than those specifically listed in Section Permitted Medications For Treatment of UC. 2. An approved non-biologic therapy in an investigational protocol. 6. Has received any investigational or approved biologic or biosimilar agent within 60 days or 5 half lives prior to the screening (whichever is longer). 7. Has previously received natalizumab, efalizumab, adalimumab, AMG-181, anti-mucosal addressin cell adhesion molecule-1 antibodies, or rituximab. 8. Has previously received vedolizumab. 9. Has history or evidence of adenomatous colonic polyps that have not been removed, or colonic mucosal dysplasia. 10. Evidence of an active infection during Screening. 11. Evidence of, or treatment for, Clostridium difficile (C. difficile) or other intestinal pathogen within 28 days prior to the 1st dose of study drug. 12. Has chronic hepatitis B virus (HBV) infection\* or chronic hepatitis C virus (HCV) infection (\* HBV immune participants, ie, being hepatitis B surface antigen \[HBsAg\], may participate). 13. Has active or latent TB, regardless of treatment history. 14. Has used a topical (rectal) treatment with (5-ASA) or corticosteroid enemas/suppositories within 2 weeks of the administration of the 1st dose of study drug. 15. Has a positive progressive multifocal leukoencephalopathy (PML) subjective symptom checklist prior to the administration of the first dose of study drug.