May 28, 2015
2 min read

FDA approves Viberzi, Xifaxan for IBS-D

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The FDA has announced its approval of two new treatments for adult patients with diarrhea-predominant irritable bowel syndrome.

“For some people, IBS can be quite disabling, and no one medication works for all patients suffering from this gastrointestinal disorder,” Julie Beitz, MD, director of the Office of Drug Evaluation III in FDA’s Center for Drug Evaluation and Research, said in an FDA press release. “The approval of two new therapies underscores the FDA’s commitment to providing additional treatment options for IBS patients and their doctors.”

Viberzi (eluxadoline, Patheon Pharmaceuticals) is taken twice a day orally with food, contains a new active ingredient and activates nervous system receptors that may reduce bowel contractions, according to the release.

This approval follows two double-blind, placebo-controlled trials involving 2,425 patients, which demonstrated eluxadoline was superior to placebo in improving abdominal pain and stool consistency over 26 weeks. Common side effects included constipation, nausea and abdominal pain and the most serious known risk is spasm in the sphincter of Oddi, which can lead to pancreatitis. Patients with a history of bile duct obstruction, pancreatitis, severe liver impairment or severe constipation, or patients who consume more than three alcoholic drinks per day should not take eluxadoline, the release said.

Xifaxin (rifaximin, Salix Pharmaceuticals) is an antibiotic derived from rifampin previously approved for travelers’ diarrhea caused by E. coli and for reducing risk of recurring overt hepatic encephalopathy in adults, according to the release. It may be taken orally three times a day for 2 weeks, and patients who have symptom recurrence can be retreated for 2 additional weeks, but no more than twice. Its treatment mechanism for IBS-D is thought to be related to changes in gut bacteria.

Its approval follows three double-blind, placebo-controlled trials demonstrating its safety and efficacy. The first two — which involved 1,258 patients who received rifaximin or placebo for 2 weeks and were then followed for 10 weeks — showed more patients in the treatment arm reported improved abdominal pain and stool consistency. The third trial assessed repeat courses for recurrent symptoms in 636 patients who received rifaximin or placebo for two additional 2-week courses separated by 10 weeks and showed more patients in the treatment arm had improved abdominal pain and stool consistency. Common side effects included nausea and increased alanine aminotransferase. Evaluation for Clostridium difficile enterocolitis should be performed in patients whose diarrhea does not improve or worsens after treatment, and caution should be used in patients taking certain other drugs or who have severe liver impairment, the release said.

Disclosure: Beitz’s relevant financial disclosures are unknown at this time.