Study to Assess the Efficacy and Safety of Rifaximin Administered BID in the Treatment of Patients With Diarrhea-Associated Irritable Bowel Syndrome

Condition(s) targeted: Irritable Bowel Syndrome

Intervention: Rifaximin (Drug)

Phase: Phase 2

Status: Completed

Sponsored by: Salix Pharmaceuticals

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.

Official title: Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Assess The Efficacy and Safety of Three Different Doses (275, 550 AND 1100 MG) of Rifaximin Administered BID For Either Two or Four Weeks in The Treatment of Patients With Diarrhea-Associated Irritable Bowel Syndrome

Study design: Treatment, Randomized, Double-Blind, Placebo Control, Parallel Assignment, Efficacy Study

Primary outcome: 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:

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.

Detailed description: 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.

Minimum age: 18 Years. Maximum age: N/A. Gender(s): Both.

Criteria:

Inclusion Criteria:

1. Male or female subject 18 years of age or older.

2. Irritable bowel syndrome confirmed by the Rome II Criteria

3. Lower endoscopic examination that demonstrates normal colonic anatomy

Exclusion Criteria:

1. Subject has exclusively constipation-predominant IBS (CIBS) that is characterized by < 3 bowel movements/week or hard and lumpy stools.

2. Subject has alternating IBS, but is currently presenting with constipation associated IBS symptoms.

3. Subject has had adequate control of their DIBS and their symptom of bloating the week preceding the screening visit or at the time of randomization. Bloating includes the following symptoms: abdominal fullness, bloating, gas, or swelling.

4. Subjects has a positive stool culture for O & P (ovum and parasite) and/or Clostridium difficile

5. Subject has failed to record 2 negative weekly global assessments during the past 10 days prior to randomization.

Premeire Pharmaceutical Research, Tempe, Arizona 85282, United States

Mayo Clinic Scottsdale, Scottsdale, Arizona 85259, United States

Medical Associates Research Group, San Diego, California 92123, United States

Lovelace Scientific Resources, Irvine, California 92618, United States

Advanced Clinical Research Institute, Anaheim, California 92801, United States

Beverly Hills Gastroenterology, Los Angeles, California 90067, United States

West Gastroenterology Medical Group, Los Angeles, California 90045, United States

Litchfield County Gastroenterology Associates, LLC, Torrington, Connecticut 06790, United States

Gastroenterology Associates of Fairfield County, Bridgeport, Connecticut 06606, United States

Connecticut Gastroenterology Institute, Bristol, Connecticut 06010-0977, United States

Research Consultants Group, Hialeah, Florida 33016, United States

Borland-Groover Clinic, Jacksonville, Florida 32256, United States

Florida Medical Clinic, Zephyrhills, Florida 33542, United States

University Clinical Research, Deland, Florida 32720, United States

Miami Research Associates, Miami, Florida 33173, United States

Shafran Gastroenterology, Winter Park, Florida 32789, United States

Advanced Gastroenterology Associates, Palm Harbor, Florida 34684, United States

Clinical Research of West Florida, Clearwater, Florida 33765, United States

Rockford Gastroenterology, Rockford, Illinois 61107, United States

Indianapolis Gastroenterology Research Foundation, Indianapolis, Indiana 46237, United States

Community Clinical Research Center, Anderson, Indiana 46016, United States

Gastrointestinal Clinic of Quad Citites, Davenport, Iowa 52807, United States

University of Kansas Medical Center, Kansas City, Kansas 66160-7350, United States

Maryland Clinical Trials, Severna Park, Maryland 21146, United States

Chevy Chase Clinical Research, Chevy Chase, Maryland 20815, United States

Digestive Disorders Associates, Annapolis, Maryland 21401, United States

Capital Gastroenterology Consultants, PA, Silver Springs, Maryland 20901, United States

Washington County Hospital, Hagerstown, Maryland 21740, United States

Coastal Research Associates, Braintree, Massachusetts 02184, United States

Henry Ford Hospital, Chesterfield, Michigan 48047, United States

Gastrointestinal Associates, PA, Jackson, Mississippi 39202, United States

Digestive Health Specialists, PA, Tupelo, Mississippi 38801, United States

Center for Digestive & Liver Diseases, Inc., Mexico, Missouri 65265, United States

Specialist in Gastroenterology, St. Louis, Missouri 63141, United States

Gastroenterology and Hepatology, Kansas City, Missouri 64131, United States

Gastroenterology Specialities, Lincoln, Nebraska 68503, United States

New York Center for Clinical Research, Lake Success, New York 11042, United States

Long Island Clinical Research, Great Neck, New York 11021, United States

Wake Research Associates, Raleigh, North Carolina 27612, United States

East Carolina Gastroenterology, Jacksonville, North Carolina 28546, United States

Rocky Mount, North Carolina 27804, United States

Asheville Gastroenterology Associates, Asheville, North Carolina 28801, United States

Hanover Medical Specialists, PA, Wilmington, North Carolina 28401, United States

Bethany Medical Center, High Point, North Carolina 27262, United States

Charlotte Gastroenterology & Hepatology, Charlotte, North Carolina 28207, United States

University of North Carolina, Chapel Hill, North Carolina 27579, United States

Carolina Research, Greenville, North Carolina 27834, United States

Vital re:Search, Greensboro, North Carolina 27408, United States

GI & Liver Diseases Consultants, Dayton, Ohio 45440, United States

Digestive Health Network, Cincinnati, Ohio 45220, United States

Wells Institute for Health Awareness, Kettering, Ohio 45429, United States

Consultants for Clinical Research, Cincinnati, Ohio 45219, United States

Digestive Health Specialists, PA, Oklahoma City, Oklahoma 73112, United States

Oklahoma Foundation for Digestive Research, Oklahoma City, Oklahoma 73104, United States

West Hills Gastroenterology Associates, PC, Portland, Oregon 97225, United States

Columbia Gastroenterology Associates, Columbia, South Carolina 29203, United States

ClinSearch, Chattanooga, Tennessee 37404, United States

Regional Research Institute, Jackson, Tennessee 38305, United States

Holston Valley Physicians, Kingsport, Tennessee 37660, United States

Austin Gastroenterology, Austin, Texas 78745, United States

Advanced Research Institute, Ogden, Utah 84405, United States

University of Utah School of Medicine, Salt Lake City, Utah 84132, United States

Internal Medicine Associates, Danville, Virginia 24541, United States

Spokane Digestive Disease Center, Spokane, Washington 99204, United States

North Pacific Clinical Research, Redmond, Washington 98052, United States

Northwest Gastroenterology Associates, Bellevue, Washington 98004, United States

Wisconsin Center for Advanced Research, Milwaukee, Wisconsin 53215, United States

Starting date: December 2005
Last updated: December 6, 2007