Sponsor's decision

Colonic microbiota changes may play a key role in the pathogenesis of acute diverticulitis. A previous proof-of-concept study suggests that rifaximin, a low-absorbable oral antibiotic, may be beneficial for prevention of acute diverticulitis recurrence by modulating the gut microflora.

The main objective of this study is to evaluate the safety and efficacy of two different doses of a delayed release formulation of rifaximin, versus placebo, for the prevention of recurrence of acute diverticulitis and diverticular complications in patients with a recent episode of acute diverticulitis.

Key Inclusion Criteria:

• Men and women aged 18-80 years at screening.
• Female participants must be either of non-childbearing potential or of childbearing potential with a negative pregnancy test result at screening and randomization AND agreeing to use a highly effective method of contraception.
• A previous documented episode of diverticulitis between 30 and 180 days prior to screening.
• Clinical remission from acute diverticulitis at screening

Key Exclusion Criteria:

• History of two or more acute diverticulitis episodes or history of any diverticular complication.
• Any documented current organic disease of the gastrointestinal tract other than diverticulosis
• Laboratory signs of clinically significant acute inflammation or signs/symptoms of diverticular complications.
• Diagnosis or history of inflammatory bowel disease (or other conditions associated with ulcerative lesions of the intestinal tract).
• Patients with positive Clostridium difficile toxin stool assay.
• Use of marketed rifaximin (or neomycin or other low-absorbable oral antibiotics) during or after the previous episode of acute diverticulitis.
• Severe hepatic impairment
• Severe kidney impairment
• Any other current significant health condition that in the Investigator's judgement may: i) jeopardize the patient's safe participation in the trial or ii) make unlikely the patient's completion of the study or iii) make unlikely the patient's compliance with the study procedures.
• History of hypersensitivity to rifaximin, rifamycin-derivatives or any of the rifaximin delayed release or placebo excipients.

NOTE: Other protocol defined Inclusion/Exclusion criteria apply