A Study to Evaluate the Efficacy and Safety of Vedolizumab in the Treatment of Chronic Pouchitis

Inclusion Criteria

• In the opinion of the investigator, the participant is capable of understanding and complying with protocol requirements.
• The participant or, when applicable, the participant's legally acceptable representative signs and dates a written, informed consent form and any required privacy authorization prior to the initiation of any study procedures.
• Has a history of ileal pouch anal anastomosis (IPAA) for ulcerative colitis (UC) completed at least 1 year prior to the Day 1 (Randomization) Visit.
• Has pouchitis that is chronic or recurrent, defined by an modified pouchitis disease activity index (mPDAI) score ≥5 assessed as average from 3 days immediately prior to the Baseline endoscopy and a minimum endoscopic subscore of 2 (outside the staple or suture line) with either (a) ≥3 recurrent episodes within 1 year prior to the Screening Period treated with ≥2 weeks of antibiotic or other prescription therapy, or (b) requiring maintenance antibiotic therapy taken continuously for ≥4 weeks immediately prior to the Baseline Endoscopy Visit.
• Agrees to take ciprofloxacin (500 mg twice daily) on Day 1 and through Week 4, regardless of the previous treatment and to stop any previous antibiotic therapy on Day 1 of the study (additional courses of antibiotics will be allowed, as needed, for flares after Week 14).
• A male participant who is nonsterilized and sexually active with a female partner of childbearing potential agrees to use a barrier method of contraception (e.g., condom with spermicide) from signing of informed consent throughout the duration of the study and for 18 weeks after last dose. The female partner of a male participant should also be advised to use a highly effective method of contraception.
• A female participant of childbearing potential who is sexually active with a nonsterilized male partner agrees to use a highly effective method of contraception from signing of informed consent throughout the duration of the study and for 18 weeks after last dose.

Exclusion Criteria

Gastrointestinal Exclusion Criteria

• Has Crohn's disease (CD), or CD of the pouch.
• Has irritable pouch syndrome (IPS).
• Has isolated or predominant cuffitis.
• Has mechanical complications of the pouch (e.g., pouch stricture or pouch fistula).
• Currently requires or has a planned surgical intervention for UC during the study.
• Has diverting stoma.

Infectious Disease Exclusion Criteria 1. Has evidence of an active infection (e.g., sepsis, cytomegalovirus, or listeriosis) during Screening.

• Has active or latent tuberculosis (TB), regardless of treatment history, as evidenced by any of the following:
• A diagnostic TB test performed within 30 days 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 tuberculin skin test reaction ≥10 mm (≥5 mm in participants receiving the equivalent of >15 mg/day prednisone).

OR

• Chest X-ray within 3 months prior to Day 1 that is suspicious for pulmonary TB, and a positive or 2 successive indeterminate QuantiFERON test within 30 days prior to Screening or during the Screening Period.
• Has chronic hepatitis B virus (HBV) infection* or chronic hepatitis C virus (HCV) infection** or a known history of human immunodeficiency virus (HIV) infection (or is found to be seropositive at Screening) or participant is immunodeficient (e.g., due to organ transplantation, history of common variable immunodeficiency, etc).
• Participants who are positive for hepatitis B virus surface antigen (HBsAg) will be excluded. For participants who are negative for HBsAg but are positive for either surface antibodies and/or core antibodies, HBV Deoxyribonucleic acid (DNA) polymerase chain reaction will be performed and if any test result meets or exceeds detection sensitivity, the participant will be excluded.
• If participant is HCV antibody positive, then a viral load test