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 screeningby 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 priorto the randomization.

3. Has evidence of ulcerative colitis proximal to the rectum (>=15 centimeter [cm] ofinvolved colon).

4. With extensive colitis (up to the hepatic flexure) or pancolitis of >8 years durationor left-sided colitis of >12 years duration must have documented evidence that asurveillance colonoscopy was performed within 12 months of the initial screening visit (may be performed during the Screening Period).

5. The participant:

6. Has had previous treatment with tumor necrosis factor- alpha (TNF-alpha)antagonists without documented clinical response to treatment (example, due tolack of response [primary nonresponders], loss of response, or intolerance [secondary nonresponders]), or

7. Has previously used a TNF-alpha antagonists (except adalimumab), and discontinuedits use due to reasons other than safety, or

8. 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 microscopiccolitis.

5. Has received any of the following for the treatment of underlying disease within 30days of randomization:

6. Non-biologic therapies (example, cyclosporine, tacrolimus, thalidomide) otherthan those specifically listed in Section Permitted Medications For Treatment ofUC.

7. An approved non-biologic therapy in an investigational protocol.

8. Has received any investigational or approved biologic or biosimilar agent within 60days or 5 half lives prior to the screening (whichever is longer).

9. Has previously received natalizumab, efalizumab, adalimumab, AMG-181, anti-mucosaladdressin cell adhesion molecule-1 antibodies, or rituximab.

10. Has previously received vedolizumab.

11. Has history or evidence of adenomatous colonic polyps that have not been removed, orcolonic mucosal dysplasia.

12. Evidence of an active infection during Screening.

13. Evidence of, or treatment for, Clostridium difficile (C. difficile) or otherintestinal pathogen within 28 days prior to the 1st dose of study drug.

14. 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).

15. Has active or latent TB, regardless of treatment history.

16. Has used a topical (rectal) treatment with (5-ASA) or corticosteroidenemas/suppositories within 2 weeks of the administration of the 1st dose of studydrug.

17. Has a positive progressive multifocal leukoencephalopathy (PML) subjective symptomchecklist prior to the administration of the first dose of study drug.