The response of patients with bile acid diarrhoea to the farnesoid X receptor agonist obeticholic acid

BackgroundBile acid diarrhoea is a common cause of chronic diarrhoea, occurring as a primary condition or secondary to ileal disease or resection. Many patients have reduced levels of the ileal hormone fibroblast growth factor 19 (FGF19), an inhibitory regulator of hepatic bile acid synthesis, secreted in response to farnesoid X receptor (FXR) activation. AimTo investigate whether obeticholic acid, a potent FXR agonist, could increase FGF19 in patients with bile acid diarrhoea, and produce clinical benefits. MethodsAfter a 2week run-in when bile acid sequestrants were discontinued, patients with previously diagnosed primary bile acid diarrhoea (n=10), secondary bile acid diarrhoea (n=10) or idiopathic chronic diarrhoea (n=8), received oral obeticholic acid 25mg daily for 2weeks. Serum FGF19, total bile acids and 7-OH-4-cholesten-3-one (C4) were measured, symptoms recorded and a diarrhoea index calculated. ResultsIn primary bile acid diarrhoea, obeticholic acid increased median fasting FGF19 (133-237pg/mL, P=0.007) and significantly reduced fasting C4 and bile acid responses. Improvements occurred in median stool frequency (-24% after 2weeks treatment, P=0.03), stool form (-14%, P=0.05) and diarrhoea index (-34%, P=0.005). In the secondary bile acid diarrhoea group, significant clinical improvements were found predominantly in patients with shorter ileal resections. Symptoms of abdominal pain and urgency improved. FGF19 and bile acids changed in the control group, without significant clinical improvement. Total and LDL-cholesterol increased and triglycerides decreased. Obeticholic acid treatment was well tolerated. ConclusionsThis proof-of-concept study indicates that obeticholic acid stimulates FGF19, reduces bile acid synthesis and produces clinical benefits in bile acid diarrhoea. FXR agonists have therapeutic potential in chronic diarrhoea. EudraCT 2011-003777-28; Clinical Trials: NCT01585025