Salix' rifaximin effective in Ph II IBS-d study

The USA's Salix Pharmaceuticals says findings from two analyses of a Phase II trial demonstrate the utility of rifaximin in the treatment of patients with diarrhea-predominant irritable bowel syndrome. Data presented at the annual meeting of the American College of Gastroenterology, in Orlando, Florida, showed that the severity of baseline IBS symptoms of abdominal pain and bloating predicted clinical response to rifaximin and demonstrated statistically greater clinical improvement in quality-of-life compared with placebo.

In a poster presentation at the ACG conference, at four weeks, the mean improvement from baseline in the overall patient quality of life score was significantly greater with rifaximin compared with placebo (20.4 versus 15.8, respectively; p=0.020). Patients in the rifaximin group also reported significantly greater mean improvement from baseline in QOL subscale scores for dysphoria (restlessness or agitation, 24.8 vs 19.8; p=0.027), body image (20.1 vs 14.6; p=0.012), health worry (16.0 vs 12.2; p=0.047), social reaction (17.3 vs 13.2; p=0.047), and relationships (14.9 vs 10.7; p=0.030), compared with placebo. Rifaximin was well tolerated in the study, with a similar incidence of adverse events compared with placebo.

In a separate poster presentation from the same study, a significantly larger percentage of patients treated with rifaximin reported adequate relief of global IBS symptoms (52% vs 44% for placebo; p=0.03) and bloating (46% vs 40%; p=0.04), compared with placebo-treated subjects. In patients with mild-to-moderate abdominal pain, rifaximin produced a greater degree of improvement, compared with placebo, in global symptoms of IBS (50% vs 39%, respectively; p=0.04) and bloating (44% vs 35%; p=0.09).