This is placebo-controlled study of three rifaximin doses in patients with DIBS. Subjects will be randomized to receive daily doses of placebo BID, rifaximin 275 mg BID, rifaximin 550 mg BID, or 1100 mg BID for 14 days. These four groups will subsequently receive an additional two weeks of placebo for a total of 4 weeks of treatment. A fifth group of subjects will receive rifaximin 550 mg BID for a period of 28 days. Subjects who successfully respond to treatment at the end of the 28-day Treatment Phase will be followed in a Post-treatment Phase that includes study visits during Weeks 6, 8, 12 and 16. Subjects who relapse during the Post-treatment Phase will be discontinued from the study.
Primary Outcome Measures:
- The primary objective of this trial is to evaluate the efficacy of a 14-day course of oral rifaximin at 550 mg BID versus placebo in providing adequate relief from Diarrhea-associated IBS (DIBS) symptoms.
Secondary Outcome Measures:
- To evaluate the dose-response relationship of placebo administered for 28 days and rifaximin administered at 275 mg BID, 550 mg BID, or 1100 mg BID for 14 days;
- to evaluate the efficacy of 550 mg BID for 4 weeks to determine if there are any differences when treatment is extended for an additional 2-week period when compared to a similar dosing regimen for 2 weeks;
- to evaluate the durability of response over a 12-week Post-treatment Phase in subjects with DIBS who achieved a response during the acute Treatment Phase of the study.
Estimated Enrollment: |
525 |
Study Start Date: |
December 2005 |
While IBS is one of the most common chronic medical conditions the etiology of IBS is unknown. Although not a life-threatening illness, IBS is considered to be a serious condition that has a substantial impact on a subject's day-to-day function. IBS is characterized by abdominal pain and altered bowel habits, including diarrhea, constipation, or alternating diarrhea and constipation. Symptoms are typically intermittent but may be continuous.