A Study to Learn About the Safety of Vedolizumab and How Well it Works in Children and Teenagers With Active Chronic Pouchitis

Exclusion Criteria

• •1. Has symptoms believed to be predominantly due to irritable pouch syndrome.
• •2. Has isolated cuffitis.
• •3. Is found to have dysplasia at the screening endoscopy.
• •4. Has mechanical complications of the pouch (for example \[e.g.\] pouch stricture or pouch fistula).
• •5. Currently requires or has a planned surgical intervention during the study.
• •6. Has a diverting stoma.
• •7. Has evidence of an active infection (e.g. sepsis, cytomegalovirus \[CMV\], or listeriosis) during screening.
• •8. Had a clinically significant infection (e.g. pneumonia, pyelonephritis, coronavirus disease 2019 \[COVID-19\]) within 35 days before first dose of study drug.
• •9. Has active or latent tuberculosis (TB), as evidenced by a diagnostic TB test performed within 3 months of screening or during the screening period that is positive, as defined by:
• •* A positive QuantiFERON test or 2 successive indeterminate QuantiFERON tests, or
• •* A TB skin test reaction \>=5 millimeter (mm). NOTE: If participant have received Bacillus Calmette-Guérin vaccine, then a QuantiFERON TB Gold test should be performed instead of the TB skin test.
• •NOTE: Participants with documented previously treated TB with a negative QuantiFERON test can be included in the study.
• •10. Has evidence of positive hepatitis B surface antigen (HBsAg) or hepatitis B core antibody (HBcAb). Hepatitis B virus (HBV) immune participants (e.g. HBsAg negative and hepatitis B antibody positive) may, however, be included.
• •15. Is taking, has taken, or is required to take any excluded medications.
• •16. Has active cerebral/meningeal disease, signs/symptoms, or history of progressive multifocal leukoencephalopathy (PML) or any other major neurological disorders, including stroke, multiple sclerosis, brain tumor, or neurodegenerative disease.
• •17. Has evidence of dysplasia or history of malignancy other than a successfully treated nonmetastatic cutaneous squamous cell or basal cell carcinoma or localized carcinoma in situ of the cervix.
• •18. Has any unstable or uncontrolled cardiovascular, pulmonary, hepatic, renal, GI, genitourinary, hematologic, coagulation, immunological, endocrine/metabolic, neurologic, or other medical disorder that, in the opinion of the investigator, would confound the study results or compromise participant safety.