A Study of Intravenous Vedolizumab Administered Every 4 Weeks in Japanese Participants With Moderate to Severe Ulcerative Colitis or Crohn's Disease

Inclusion Criteria:

UC cohort

1. The participant has moderate to severe UC, who had previously shown clinicalresponse in initial treatment with commercially available vedolizumab IV, thenexperienced secondary loss of response during maintenance therapy with commerciallyavailable vedolizumab IV Q8W. Previous "clinical response" is to be judged by the investigators referring to oneof the following criteria.

• Reduction of >=2 points and >=25% in modified Mayo score, and a decrease of >=1point in rectal bleeding subscore or rectal bleeding subscore of =<1, from thestart of initial treatment with commercially available vedolizumab IV.

• Reduction of >=2 points and >=25% in partial Mayo score, and a decrease of >=1point in rectal bleeding subscore or rectal bleeding subscore of =<1, from thestart of initial treatment with commercially available vedolizumab IV.

• Significant improvement on endoscopy (i.e., a decrease of >=2 points in Mayoendoscopic subscore).

"Secondary loss of response" is to be judged by the investigators referring to oneof the following criteria.

• Increase of >=2 points in modified Mayo score, and an increase of >=1 point inrectal bleeding subscore or rectal bleeding subscore >=2, from the start ofmaintenance therapy with commercially available vedolizumab IV.

• Increase of >=2 points in partial Mayo score, and an increase of >=1 point inrectal bleeding subscore or rectal bleeding subscore >=2, from the start ofmaintenance therapy with commercially available vedolizumab IV.

• Significant deterioration on endoscopy (i.e., an increase of >=2 points in Mayoendoscopic subscore).

2. The participant has active UC as determined by a modified Mayo score of >=5 atbaseline (within 10 days prior to the start of treatment phase), with a Mayo rectalbleeding subscore of >=1 at baseline (within 10 days prior to the start of treatmentphase) and a Mayo endoscopic subscore of >=1 as assessed by the central reader.

CD cohort

1. The participant has moderate to severe CD, who had previously shown clinicalresponse in initial treatment with commercially available vedolizumab IV, thenexperienced secondary loss of response during maintenance therapy with commerciallyavailable vedolizumab IV Q8W. Previous "clinical response" is to be judged by the investigators referring to oneof the following criteria.

• Reduction of >=70 points in CDAI score from the start of initial treatment withcommercially available vedolizumab IV.

• Reduction of >=3 points in HBI score from the start of initial treatment withcommercially available vedolizumab IV.

"Secondary loss of response" is to be judged by the investigators referring to oneof the following criteria.

• Increase of >=70 points in CDAI score from the start of maintenance therapywith commercially available vedolizumab IV.

• Increase of >=3 points in HBI score from the start of maintenance therapy withcommercially available vedolizumab IV.

2. The participant has active CD as determined by a CDAI score of >=220 at baseline (within 10 days prior to the start of treatment phase).

3. The participant has a C-reactive protein (CRP) level >3.0 mg/L during the screeningphase.

Exclusion Criteria:

1. The participant has had extensive colonic resection, subtotal or total colectomy.

2. The participant has received any of the investigational or approved non-biologictherapies (e.g., cyclosporine, tacrolimus or tofacitinib, except for thosespecifically listed as permitted medications) for the treatment of underlyingdisease within 30 days or 5 half-lives of screening (whichever is longer).

3. The participant has received any investigational or approved biologic or biosimilaragent other than vedolizumab within 60 days or 5 half-lives of screening (whicheveris longer).

4. The participant has a clinically significant active infection (e.g., pneumonia,pyelonephritis or coronavirus disease 2019 [COVID-19]) within 30 days prior toscreening or during screening, or has an ongoing chronic infection.

5. The participant has known or suspected intolerance or hypersensitivity tovedolizumab or closely related compounds, or any of the vedolizumab IV excipients.

6. The participant has active cerebral/meningeal disease, or signs/symptoms ofprogressive multifocal leukoencephalopathy (PML) or any history of PML at screening.