A Study of Vedolizumab in Children and Teenagers With Ulcerative Colitis or Crohn's Disease

Inclusion Criteria

• The participant weighs ≥10 kg at the time of screening and enrollment into the study.
• Participants with UC or CD diagnosed at least 1 month before screening. Participants with moderately to severely active disease defined as:

• Participants with UC: a modified Mayo score of 5 to 9 (sum of Mayo endoscopic subscore, stool frequency subscore, and rectal bleeding subscore) with a Mayo endoscopic subscore of ≥2 (with the presence of mucosal friability excluding an endoscopic subscore of 1 and mandating a score of at least 2). (The results of screening endoscopy should be applied.)
• Participants with CD: a pediatric Crohn's disease activity index (PCDAI) >30 and a simple endoscopic score for Crohn's disease (SES-CD) >6 (or an SES-CD ≥4 if disease is confined to terminal ileum) at screening endoscopy.
• Participants who have failed, lost response to, or been intolerant to treatment with at least 1 of the following agents: corticosteroids, immunomodulators (for example, azathioprine [AZA], 6-mercaptopurine [6-MP], methotrexate [MTX]), and/or tumor necrosis factor (TNF)-α antagonist therapy (for example, infliximab, adalimumab).
• Participants with evidence of UC extending proximal to the rectum (that is, not limited to proctitis), at a minimum.
• Participants with extensive colitis or pancolitis of >8 years' duration or left-sided colitis of >12 years' duration must have documented evidence of a negative surveillance colonoscopy within 12 months before screening.
• Participants with vaccinations that are up-to-date based on the countrywide accepted schedule of childhood vaccines.

Exclusion Criteria

• Participants who have had previous exposure to approved or investigational anti-integrins, including but not limited to, natalizumab, efalizumab, etrolizumab, or abrilumab (AMG 181); or mucosal addressin cell adhesion molecule-1 (MAdCAM-1) antagonists (ontamalimab), or rituximab.
• Participants who have had prior exposure to vedolizumab.
• Participants with hypersensitivity or allergies to vedolizumab or any of its excipients.
• Participants with active cerebral/meningeal disease, signs/symptoms or history of progressive multifocal leukoencephalopathy (PML) or any other major neurological disorders.
• The participant has received any live vaccinations within 30 days before first dose of study drug.
• Participants who currently require surgical intervention or are anticipated to require surgical intervention for UC or CD during this study.
• Participants who have had subtotal or total colectomy or have a jejunostomy, ileostomy, colostomy, ileo-anal pouch, known fixed stenosis of the intestine, short bowel syndrome, or >3 small intestine resections.
• Participants with a current diagnosis of indeterminate colitis.
• Participants with clinical features suggesting monogenic very early-onset inflammatory bowel disease (IBD).
• Participants with active or latent tuberculosis (TB).
• Participants with evidence of positive hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb). Hepatitis B virus (HBV) immune subjects (that is, HBsAg negative and hepatitis B surface antibody [anti-HBs]-positive) may, however, be included.
• The participant has any identified congenital or acquired immunodeficiency (for example, common variable immunodeficiency, human immunodeficiency virus [HIV] infection, organ transplantation).
• Participants with positive stool studies for ova and/or parasites or stool culture at screening visit.
• Participants with positive Clostridioides difficile (C difficile) stool test at screening visit.