As good as it gets

Last week's FDA panel meeting to discuss an NDA for rifaximin from Salix Pharmaceuticals Ltd. provided the agency with exactly the kind of assistance advisory committees are meant to offer. In considering approval of a new dosage strength of the antibiotic for use in hepatic encephalopathy - a complex disease for which there is no established development or regulatory path - the committee determined that use of a subjective assessment tool, while less than ideal, provided adequate evidence to support the product's risk-benefit profile.

Salix markets rifaximin in the U.S. as Xifaxan in a 200 mg tablet form that is indicated for thrice-daily use to treat travelers' diarrhea. For hepatic encephalopathy (HE), the company is developing a 550 mg tablet that is given twice daily. If FDA follows the committee's recommendation, rifaximin would be the first drug approved for HE in 30 years...