Clinical Research Directory

Inclusion Criteria: 1. Has a diagnosis of ulcerative colitis (UC) established at least 3 months prior to Screening by clinical and endoscopic evidence corroborated by a histopathology report. Cases of UC established at least 6 months before randomization for which a histopathology report is not available will be considered based on the weight of evidence supporting the diagnosis and excluding other potential diagnoses and must be discussed with the sponsor on a case-by case basis before randomization. 2. Has moderately to severely active UC as determined by a complete Mayo score of 6-12 with an endoscopic subscore ≥2 within 10 days prior to the first dose of IP. The endoscopy can be performed during the Screening Phase (Day -10 to Day -5 to allow for central reading prior to first dose at Week 0). 3. Has evidence of UC extending proximal to the rectum (≥15 cm of involved colon). 4. Participants with extensive colitis or pancolitis of \>8 years duration or left-sided colitis \>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 screening). 5. Participants with a family history of colorectal cancer, personal history of increased colorectal cancer risk, age \>50 years, or other known risk factors must be up-to-date on colorectal cancer surveillance (may be performed during screening). 6. Has demonstrated an inadequate response to, loss of response to, or intolerance of at least 1 of the following agents: corticosteroids, immunomodulators, or tumor necrosis factor alpha (TNF-α) antagonists. Exclusion Criteria: 1. Has evidence of abdominal abscess or toxic megacolon at the initial Screening Visit. 2. Has had extensive colonic resection, subtotal or total colectomy. 3. Has an existing ileostomy, colostomy, or known fixed symptomatic stenosis of the intestine. A history of ileostomy or colostomy that has been reversed may be acceptable. 4. Has had any previous exposure to approved or investigational anti-integrins (for example, natalizumab, efalizumab, etrolizumab, or AMG-181) or mucosal address in cell adhesion molecule-1 (MAdCAM-1) antagonist, or rituximab. 5. Has used a topical (rectal) treatment with 5-acetyl salicylic acid (5-ASA) or corticosteroid enemas/suppositories or traditional Chinese medications for treatment of UC within 2 weeks of the administration of the first dose of IP. 6. Currently requires or is anticipated to require surgical intervention for UC during the study. 7. Has a history or evidence of adenomatous colonic polyps that have not been removed or has a history or evidence of colonic mucosal dysplasia including low or high-grade dysplasia, as well as indeterminate for dysplasia. 8. Has a suspected or confirmed diagnosis of Crohn's enterocolitis, indeterminate colitis, ischemic colitis, radiation colitis, diverticular disease associated with colitis, or microscopic colitis. 9. Has evidence of or has had treatment for C. difficile infection or other intestinal pathogen within 28 days prior to randomization. 10. Has chronic hepatitis B virus (HBV) infection or chronic hepatitis C virus (HCV) infection. 11. Has active or latent TB. 12. Has any identified congenital or acquired immunodeficiency (for example, common variable immunodeficiency, human immunodeficiency virus \[HIV\] infection, organ transplantation). 13. Has any history of malignancy, except for the following: (a) adequately treated non-metastatic basal cell skin cancer; (b) squamous cell skin cancer that has been adequately treated and that has not recurred for at least 1 year prior to randomization; and (c) history of cervical carcinoma in situ that has been adequately treated and that has not recurred for at least 3 years prior to randomization. Subjects with remote history of malignancy (for example, \>10 years since completion of curative therapy without recurrence) will be considered based on the nature of the malignancy and the therapy received and must be discussed with the sponsor on a case-by-case basis prior to randomization. 14. Has a history of any major neurological disorders, including stroke, multiple sclerosis, brain tumor, or neurodegenerative disease. 15. Has a positive progressive multifocal leukoencephalopathy (PML) subjective symptom checklist at Screening or prior to the administration of the first dose of IP at Week 0.