Studies show XIFAXAN 550 mg tablets demonstrate significant relief of global IBS symptoms

Jan 6 2011

Salix Pharmaceuticals, Ltd. (NASDAQ:SLXP) today announced the New England Journal of Medicine has published results from TARGET 1 and TARGET 2, the Company's two pivotal Phase 3 efficacy and safety studies of XIFAXAN^® (rifaximin) 550 mg tablets for the treatment of Irritable Bowel Syndrome without constipation, or Non-C IBS. The studies showed XIFAXAN 550 mg tablets demonstrated a statistically significant improvement for the adequate relief of global IBS symptoms, IBS-related bloating, abdominal pain and stool consistency following completion of a 14-day course of therapy. IBS, one of the most common chronic medical conditions, is characterized by altered bowel habits with bloating, abdominal pain and discomfort. The FDA is currently reviewing Salix's supplemental New Drug Application (sNDA) for XIFAXAN 550 mg tablets for the proposed indication of the treatment of Non-C IBS. The Prescription Drug User Fee Act (PDUFA) goal date for the Agency's Priority Review of the application is March 7, 2011.

TARGET 1 and TARGET 2 - two identically-designed 600-plus patient, double-blind, placebo-controlled trials - demonstrated that a 14-day course of XIFAXAN 550 mg, taken 3 times daily, achieved adequate relief of global IBS symptoms (primary endpoint) and adequate relief of IBS-related bloating (key secondary endpoint) in a significantly greater proportion of patients, compared with placebo, during the primary evaluation period (first 4 weeks following treatment) as well as during the entire study period (10 weeks following treatment). The statistically significant weekly findings in the primary endpoint and key secondary endpoint noted above were supported by daily findings in the secondary endpoints of global IBS symptoms, bloating, stool consistency and abdominal pain and discomfort. Additionally, the NEJM publication includes results of an analysis of a composite endpoint of abdominal pain or discomfort and loose or watery stools as outlined in the March 2010 draft FDA Guidance for Industry relating to the clinical evaluation of products for treatment of IBS.

"An alteration in gut flora has been proposed as an important contributor to the pathophysiology of IBS that might underlie some of the gastrointestinal symptoms associated with this condition," said Mark Pimentel, M.D., Gastrointestinal Motility Program Director at Cedars-Sinai Medical Center and Principal Investigator of the clinical trials. "These findings conclusively show that a targeted, gut-selective antibiotic such as rifaximin can provide long-lasting results."

"These findings show the potential of rifaximin to treat multiple symptoms of IBS and affect gut flora, an underlying cause of IBS, with a side effect profile comparable to placebo," said Bill Forbes, PharmD., Executive Vice President of Research and Development and Chief Development Officer at Salix Pharmaceuticals. "Rifaximin's utility to treat the underlying causes of IBS symptoms is a significant scientific development for patients suffering from symptoms associated with IBS without constipation, including bloating, abdominal pain and diarrhea."