Twelve weeks of extended-release rifaximin at 800 mg twice daily induced remission in 62% of patients and was both safe and well tolerated.

Many clinicians use antibiotics to treat infection in patients with Crohn disease; some also use them to suppress disease activity, despite mixed evidence to support their efficacy for this purpose. Now, researchers in Europe have conducted a multicenter, double-blind, phase II trial to determine whether an extended intestinal release (EIR) form of rifaximin induces remission in patients with moderately active Crohn disease.

In this manufacturer-funded study, participants (410 adults with Crohn’s Disease Activity Index scores between 220 and 400) were randomized to receive twice-daily rifaximin-EIR (400 mg, 800 mg, or 1200 mg) or placebo for 12 weeks. Patients in remission at the end of the treatment period were followed for an additional 12 weeks. A total of 402 patients received at least one dose of study drug and were included in the full analysis.

At the end of treatment, the remission rate was higher in the 800-mg rifaximin group than in the placebo group (62% vs. 43%; P=0.005). The difference was maintained throughout the follow-up period (at 24 weeks, 45% vs. 29%; P=0.02). Remission rates were 54% in the 400-mg group and 47% in the 1200-mg group and were not significantly different from the placebo group rate. Dropout because of adverse events was significantly more common in the 1200-mg group than in any of the other groups.

Comment: These results support a role for bacteria in the pathogenesis of Crohn disease. The extended-release formulation of rifaximin used in this trial is not yet available in the U.S.

Source: Journal Watch Gastroenterology