One Year Study of Rifaximin Delayed Release (DR) in Crohn's Disease

RECD3126 is a double-blind, placebo-controlled, parallel-group, multicenter, multiregional,
52-week study to assess the efficacy and safety of rifaximin DR tablets for the induction of
clinical remission and endoscopic response at 16 weeks followed by clinical and endoscopic
remission after 52 weeks of continuous therapy in subjects with active moderate Crohn's
disease.

Subjects will be randomized in a 1:1 allocation to rifaximin or placebo at the beginning of
the treatment period and will maintain treatment assignment throughout the duration of the
study. Ileocolonoscopy will be performed on all subjects at baseline, between Weeks 16 and
17 (end of the Induction Phase), and following completion of the 36-week Long Term Treatment
Phase (Week 52).

Major Inclusion Criteria:

- Moderate, non-fistulizing Crohn's disease in the ileum and/or prior to randomization;
and a SES-CD score of ≥7 (confirmed by centralized endoscopy reading).

- During the Screening Period, the subject will need to have certain average daily
scores for abdominal pain and average number of liquid/very soft stools.

Major Exclusion Criteria:

- Pregnant or lactating females. Females of childbearing (reproductive) potential must
have a negative serum pregnancy test at screening and agree to use a highly effective
method(s) of contraception throughout their participation in the study.

- Diagnosis of ulcerative or indeterminate colitis.

- Diagnosis of Celiac Disease.

- Bowel surgery within 12 weeks prior to screening and/or has surgery planned or deemed
likely for Crohn's disease during the study period.

- Presence of an ileostomy or colostomy.

- Known fixed symptomatic stenosis/stricture of the small or large bowel.

- Had more than one segmental colonic resection.

- Had more than 3 small bowel resections or symptoms associated with short bowel
syndrome.

- Current evidence of peritonitis.

- History or evidence of colonic mucosal dysplasia.

- History or evidence of adenomatous colonic polyps that have not been removed.

- Unwilling to be tapered off corticosteroids by Week 8 or the subject is known by the
Investigator to be steroid dependent.

- Has used a biologic within 12 weeks of randomization.

- Used cyclosporine, tacrolimus, sirolimus, mycophenolate mofetil, or similar drugs
within 8 weeks prior to randomization.

- Had rectal administration of 5-aminosalicylic acid (5-ASA) or corticosteroid
enemas/foams/ suppositories within 2 weeks prior to screening visit.