A Study to Assess Whether Etrolizumab is a Safe and Effective Treatment for Participants With Moderately to Severely Active Crohn's Disease (CD)

Inclusion Criteria:

- Moderately to severely active CD as determined by the CDAI, patient reported outcomes
and endoscopically defined disease activity in the ileum and/or colon

- Intolerance, refractory disease, or no response to CS, IS, or anti-TNF therapy within
5 years from screening. Participants who have not previously demonstrated inadequate
response or intolerance to one or more anti-TNF therapies are eligible to participate
in the study provided they are intolerant or refractory to CS or IS therapy

- Use of effective contraception as defined by the protocol

Exclusion Criteria:

- A history of, or current conditions affecting the digestive tract, such as ulcerative
colitis, indeterminate colitis, fistulizing disease, abdominal or perianal abscess,
adenomatous colonic polyps not excised, colonic mucosal dysplasia, and short bowel
syndrome

- Planned surgery for CD

- Ileostomy or colostomy

- Has received non-permitted inflammatory bowel disease (IBD) therapies (including
natalizumab, vedolizumab, and efalizumab, as stated in the protocol)

- Any prior treatment with ustekinumab within 14 weeks prior to randomization

- Chronic hepatitis B or C infection, human immunodeficiency virus (HIV), active or
latent tuberculosis (participants with prior history of Bacillus Calmette-Guérin [BCG]
vaccination must pass protocol-defined screening criteria)

- Sinus tract with evidence for infection (e.g., purulent discharge) in the clinical
judgment of the investigator. Fistulas related to CD are not exclusionary

- Any prior treatment with anti-adhesion molecules (e.g., anti-mucosal addressin cell
adhesion molecule [anti-MAdCAM-1])

- Any major episode of infection requiring treatment with intravenous antibiotics weeks prior to screening or oral antibiotics with antibiotics as adjunctive therapy for CD in the absence of documented infection
is not exclusionary

- Hospitalization (other than for elective reasons) within 4 weeks prior to
randomization