FDA approves two new IBS medicines

The FDA has approved two new treatments for irritable bowel syndrome with diarrhoea (IBS-D) in the form of Actavis' Viberzi (eluxadoline) and Salix' Xifaxan (rifaximin). 

According to the National Institutes of Health, patients with irritable bowel syndrome (IBS) experience a number of signs and symptoms, including pain or discomfort in the abdomen and changes in bowel movement patterns. Studies estimate that IBS affects 10 to 15% of adults in the US.  

These new medicines work on a sub-set of IBS known as IBS-D, which is characterised mainly by loose or watery stools at least 25% of the time.

Viberzi, which contains a new active ingredient, comes in pill form and works by activating receptors in the nervous system that can lessen bowel contractions. 

Viberzi is intended to treat adults with IBS-D but has been designated as a controlled substance, and must be approved by the Drugs Enforcement Agency (DEA).

David Nicholson, executive VP at Actavis global brands R&D, said: “The FDA's approval of Viberzi is the first step to providing physicians with a new, evidence-based, treatment option for their adult patients with IBS-D.

“At Actavis, we are dedicated to providing new treatment options, and the development of new agents that help address the most bothersome symptoms of IBS-D. We are very pleased to be working with the FDA to advance this IBS-D treatment and we eagerly await DEA scheduling determination later this year.”

Xifaxan can be taken orally three times a day for 14 days, and is for the treatment of abdominal pain and diarrhoea in patients with IBS-D. 

Xifaxan, an antibiotic derived from rifampin, was previously approved as treatment for travelers' diarrhoea caused by E. coli and for reduction of the risk in adult patients of recurring overt hepatic encephalopathy, the changes in brain function that occur when the liver is unable to remove toxins from the blood. 

The exact mechanism of action of Xifaxan for treatment of IBS-D is not known, but is thought to be related to changes in the bacterial content in the gastrointestinal tract.

Julie Beitz, director of the Office of Drug Evaluation III at the FDA, said: “For some people, IBS can be quite disabling, and no one medication works for all patients suffering from this gastrointestinal disorder.”

Analysts expect Viberzi to generate US sales of about $450m by 2020 according to Thomson Reuters data. They expect Xifaxan sales for IBS-D to top $1bn.