Phase 4 study for people with Crohn's Disease and Colitis

Inclusion Criteria:

1. Adults aged 18 to 80 years, inclusive, at the time of consent;

2. Moderately to severely active CD at baseline defined by a CDAI score of 220 to 450 inclusive and SES-CD, excluding the presence of narrowing component, ≥6 (or ≥4 for participants with isolated ileal disease);

3. BWT on IUS of \>4.0 mm in the terminal ileum or any colonic segment (excluding the rectum) as assessed by the mean of 2 longitudinal and 2 cross-sectional measurements of the same segment;

4. Biologic-naïve or have previous exposure (within the last 5 years of the screening date) to no more than 1 advanced therapeutic compound (approved biologic or small molecule drug) for the treatment of their CD. Note: only approximately 15% to 30% of the enrolled population will have had prior exposure to an advanced therapeutic;

5. Participants may continue stable dose (initiated at least 4 weeks prior to Screening) of 5-ASA for CD;

6. Persons of childbearing potential must have a negative serum pregnancy test prior to randomization and must use a highly effective method of contraception throughout the study. Females unable to bear children must have documentation of such in the source records;

7. Able to participate fully in all aspects of this clinical trial;

8. Written informed consent must be obtained and documented.

Exclusion Criteria:

1. Current or previous treatment with vedolizumab, etrolizumab, or natalizumab;

2. Previously exposed to 2 or more compounds or classes of an advanced therapeutic compound (approved biologic or small molecule drug) for the treatment of their CD;

3. Change to oral corticosteroid therapy dosing within 2 weeks prior to randomization or a corticosteroid dose of \>40 mg of prednisone or equivalent at randomization;

4. Only have inflammation proximal to the terminal ileum that cannot be reached by ileocolonoscopy;

5. Have a CD complication, such as symptomatic strictures in the small bowel with \>3 cm prestenotic dilatation on any imaging modality, requiring procedural intervention;

6. Previous extensive colonic resection or missing \>2 segments out of 5 (terminal ileum, right colon, transverse colon, sigmoid and left colon, and rectum), ileorectal anastomosis, or a proctocolectomy;

7. Ostomy or ileoanal pouch;

8. Short bowel syndrome;

9. Fibrotic-only stricture in the ileum or colon without evidence of active inflammation (in the investigator's judgment), including any impassable stenosis;

10. Abscess \>2 cm, detected by IUS or endoscopy; participants with draining fistulas are not excluded;

11. Serious underlying disease other than CD that, in the opinion of the investigator, may interfere with the participant's ability to participate fully in the study or would compromise participant safety;

12. Positive stool test for Clostridioides difficile infection (as demonstrated by positive toxin);

13. Known HIV or hepatitis B or C infection. If a negative test result is available in the 12 months prior to randomization, retesting is not required;

14. Known active or latent tuberculosis (TB); if a negative test result is available in the 12 months prior to randomization, confirmatory testing (per standard of care) is not required before randomization;

15. Other systemic or opportunistic infection (including cytomegalovirus), any other clinically significant extraintestinal infection, or recurring infection within 6 months of randomization;

16. Has active cerebral/meningeal disease, signs, symptoms, or any history of progressive multifocal leukoencephalopathy (PML) prior to randomization;

17. Hypersensitivity, allergy, or intolerance to any excipient of vedolizumab or any other contraindication to vedolizumab;

18. Active severe infection such as sepsis, cytomegalovirus, listeriosis, or opportunistic infection.

19. Unwillingness to withhold protocol-prohibited medications during the trial;

20. Concurrent or previous participation in another clinical trial and received any investigational therapy within 30 days prior to randomization;

21. History of alcohol or drug abuse that in the opinion of the investigator may interfere with the participant's ability to comply with the study procedures;

22. Prior enrolment in the current study and had received study treatment;

23. Pregnant, lactating, or intending to become pregnant/impregnate a partner before, during, or within 18 weeks after the last dose; or intending to donate ova or sperm during such time period;

24. Vaccination with a live or live-attenuated vaccine within 4 weeks prior to randomization, or planned vaccination with a live or live-attenuated vaccine during participation in the study;

25. Any person performing mandatory military service, deprived of liberty, in a residential care setting, or any person who, due to a judicial decision, cannot take part in clinical studies;

26. The person is an immediate family member, study site employee, or is in a dependent relationship with a study site employee who is involved in conduct of this study (e.g., spouse, parent, child, sibling).