Rifaximin regulatory update

FDA's Gastrointestinal Drugs Advisory Committee voted 14-4 in favor of approval of an NDA from Salix for rifaximin 550 mg tablets for the maintenance of remission of hepatic encephalopathy (HE). The panel largely brushed off issues raised in the agency's briefing documents, which had raised concerns about the subjective nature of the assessment tool used to assess the primary endpoint of the lone pivotal efficacy trial, as well as a possible risk of hepatic adverse events.

The panel voted 15-3 that the clinical data provide substantial evidence of efficacy for maintenance of HE remission based on data from the double-blind Phase III RFHE 3001 trial, which showed patients receiving rifaximin twice daily had a 58% reduction in the risk of breakthrough overt HE vs. placebo (p<0.0001). The committee also voted 12-6 that the safety data for rifaximin had been adequately assessed at Salix's proposed dose and duration and 14-4 that the data were acceptable. ...