Diarrhoea drug "shows promise"

Bile acid diarrhoea (BAD), also commonly referred to as bile acid malabsorption, is a common cause of chronic diarrhoea that is thought to affect every one in 100 adults in western countries.

According to researchers, BAD is caused by excessive secretion of bile acids, a component of bile that assists digestion.

After bile is secreted into the intestine from the gall bladder, the bile acids are normally absorbed in the ileum, a part of the small intestine. But in BAD, excess bile passes into the colon and causes watery diarrhoea.

“These early findings suggest that FXR agonists could be effective for treating patients with chronic diarrhoea

ICL professor Julian Walters

A study conducted at Imperial College London (ICL) has found that the drug obeticholic acid (OCA) - which was developed by Intercept Pharmaceuticals - could be used to provide relief for patients with BAD.

Julian Walters, from the Department of Medicine at ICL, who led the study, said: “Many doctors are totally unaware of bile acid diarrhoea, but it’s more common than Crohn’s disease and ulcerative colitis. When patients are correctly diagnosed, there are specific treatments that can help them, but many people find these current drugs are unpalatable.

“The condition often has a serious impact on patients’ work and social lives, causing people to have up to ten watery bowel movements a day, often for many months, with an urgent need to go to avoid accidental incontinence.”

As part of the study, ICL researchers tested OCA in three groups of patients: 10 with primary BAD, where the intestine is otherwise healthy; 10 with secondary BAD, where malabsorption can occur as a result of another disease such as Crohn’s; and eight with other causes of chronic diarrhoea, who served as a control group.

Over the course of a six week period, in which patients received OCA medication for two weeks, results showed an improvement in symptoms in the primary BAD patients and some secondary BAD patients, but not in those with other causes of chronic diarrhoea.

“This drug represents a new potential approach to treating BAD by restoring the levels of the FGF19 hormone and so controlling bile acid production in the liver. These early findings suggest that FXR agonists could be effective for treating patients with chronic diarrhoea,” Walters said.

“This is exciting and we need larger studies to confirm this.”

OCA is the first in a new class of drugs, farnesoid X receptor (FXR) agonists, and the response of the patients to OCA shows that abnormalities in the system it targets may be critical for this condition, the researchers said.

A full account of the research has been published in the journal Alimentary Pharmacology and Therapeutics.