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Salix Presents Positive Phase 3 Investigational Study Data For Repeat Rifaximin Treatment In Patients With Diarrhea Predominant Irritable Bowel Syndrome


Salix Presents Positive Phase 3 Investigational Study Data For Repeat Rifaximin Treatment In Patients With Diarrhea Predominant Irritable Bowel Syndrome

Results Presented at Digestive Disease Week Support Reduced Risk of Patients Developing Infection

PR Newswire

WASHINGTON, June 3, 2018 /PRNewswire/ -- Salix Pharmaceuticals, a leading specialty pharmaceutical company committed to the prevention and treatment of gastrointestinal disorders, today announced the presentation of new investigational data from a post-hoc analysis of Phase 3 safety data evaluating the effect of rifaximin on risk of infections in a randomized, placebo-controlled trial of repeat treatment in adults with irritable bowel syndrome with diarrhea (IBS-D). The data was presented during an oral presentation at the annual meeting of Digestive Disease Week (DDW) being held this week in Washington, D.C. (June 2-5, 2018).

Salix Pharmaceuticals, Ltd. Logo (PRNewsfoto/Salix Pharmaceuticals, Ltd.)

"I'm encouraged by these results that help us understand the extent to which Clostridium difficile (C. Diff) may occur with Xifaxan, "said Mark Pimentel, M.D., professor of Medicine and executive director of the Medically Associated Science and Technology Program at Cedars-Sinai in Los Angeles. "This new data further supports the safety of rifaximin and reinforces yet another potential benefit for IBS-D patients who are on this treatment."

In the open-label phase, IBS-D patients (based on Rome III criteria) received treatment with rifaximin 550 mg TID for two weeks, followed by a four-week treatment-free assessment period to determine response to rifaximin. Responders were subsequently followed until IBS symptom relapse, or for up to 18 additional weeks, whichever occurred first.  Non-responders were withdrawn from the trial. Patients who relapsed were then randomly assigned to receive two, two-week repeat treatment courses of rifaximin 550 mg TID or placebo, with repeat courses separated by 10 weeks. All patients, regardless of response or relapse after the first repeat treatment underwent a second repeat treatment with the same regimen assigned at randomization.

Adverse events (AEs) were monitored throughout the study for up to 24 weeks in the open-label phase, and up to 22 weeks in the double-blind phase.  At the start of open-label rifaximin treatment, stool samples were collected and tested for Clostridium difficile Toxins A and B. Patients who tested positive were withdrawn from the study, and the positive result recorded as an AE.

Of the 2,579 patients in the open-label treatment group, infection-related AEs were experienced by 11.9% of patients, the most common being upper respiratory tract infection (1.6%). Of the 328 patients receiving rifaxamin 550 mg tablets in the double-blind group and the 308 patients receiving placebo, infection-related AEs were experienced by 18.6% and 19.8% percent of patients, respectively. Incidence of serious adverse events (SAEs) related to infection were low in both groups during the study.

"Up to 16 million Americans suffer with IBS-D, and they can live with debilitating symptoms, including abdominal pain and diarrhea,1 so it is important to understand how locally acting antibiotic, rifaximin, impacts systemic infection," said Mark McKenna, senior vice president and general manager, Salix Pharmaceuticals. "We are pleased to have this data presented at such a prominent medical meeting of physicians and researchers in the field of gastroenterology."

Rifaximin, which Salix markets in the United States, is a rifamycin antibacterial currently indicated for treatment of travelers' diarrhea (TD) caused by non-invasive strains of Escherichia coli in patients 12 years of age or older, reduction in risk of overt hepatic encephalopathy (HE) recurrence in adults and for the treatment of IBS-D in adults.

The research is being presented at DDW in Washington, D.C. on Sunday, June 3 at 5:00 p.m., Room 201 and is titled, "Lack Of Development Of Opportunistic Infections, Including Candidiasis, In Patients With Diarrhea-Predominant Irritable Bowel Syndrome Receiving Repeat Treatment With Rifaximin."


  • XIFAXAN® (rifaximin) is not for everyone. Do not take XIFAXAN if you have a known hypersensitivity to rifaximin, any of the rifamycin antimicrobial agents, or any of the components in XIFAXAN.
  • If you take antibiotics, like XIFAXAN, there is a chance you could experience diarrhea caused by an overgrowth of bacteria (C. difficile). This can cause symptoms ranging in severity from mild diarrhea to life-threatening colitis. Contact your healthcare provider if your diarrhea does not improve or worsens.
  • Talk to your healthcare provider before taking XIFAXAN if you have severe hepatic (liver) impairment, as this may cause increased effects of the medicine.
  • Tell your healthcare provider if you are taking drugs called P-glycoprotein and/or OATPs inhibitors (such as cyclosporine) because using these drugs with XIFAXAN may lead to an increase in the amount of XIFAXAN absorbed by your body.
  • In clinical studies, the most common side effects of XIFAXAN in IBS-D were nausea (feeling sick to your stomach) and an increase in liver enzymes.
  • XIFAXAN may affect warfarin activity when taken together. Tell your healthcare provider if you are taking warfarin because the dose of warfarin may need to be adjusted to maintain proper blood-thinning effect.
  • If you are pregnant, planning to become pregnant, or nursing, talk to your healthcare provider before taking XIFAXAN because XIFAXAN may cause harm to an unborn baby or nursing infant.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit  or call 1-800-FDA-1088.

For product information, adverse event reports, and product complaint reports, please contact:
Salix Product Information Call Center
Phone: 1-800-321-4576
Fax: 1-510-595-8183

Please click here for full Prescribing Information.

About Salix
Salix Pharmaceuticals is one of the largest specialty pharmaceutical companies in the world committed to the prevention and treatment of gastrointestinal diseases. For almost 30 years, Salix has licensed, developed and marketed innovative products to improve patients' lives and arm health care providers with life-changing solutions for many chronic and debilitating conditions. Salix currently markets its product line to U.S. health care providers through an expanded sales force that focuses on gastroenterology, hepatology, pain specialists and primary care. Salix, a wholly owned subsidiary of Valeant Pharmaceuticals International, Inc., is headquartered in Bridgewater, New Jersey.

1 Grundmann O, Yoon SL. Irritable bowel syndrome: epidemiology, diagnosis and treatment: an update for health-care practitioners. J Gastroenterol Hepatol. 2010 Apr;25(4):691-9.

The Xifaxan 550 mg product and the Xifaxan trademark are licensed by Alfasigma Salix Pharmaceuticals or its affiliates. SAL.0068.USA.18

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