Attenuated Familial Adenomatous Polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant inherited disorder linked to a mutation in the APC gene, associated with the development of multiple colonic and duodenal adenomas, which in 100% of cases progress to colorectal cancer (CRC) if left untreated. Management of affected patients is usually based on prophylactic total colectomy with or without rectal preservation, followed by regular endoscopic surveillance of the duodenum and rectum or ileal reservoir. However, there is considerable inter- and intra-familial variability in the rate of adenoma appearance and development for identical mutations. This strongly suggests the additional role of environmental factors. Recently, the gut microbiota has been identified as a co-factor of carcinogenesis in patients with FAP, but no prospective evaluation of the association between the incidence and severity of adenomatous proliferations and a microbiological signature has been studied, particularly at duodenal level in operated patient.

This phase IIa trial investigates if giving obeticholic acid (OCA) is safe and has a beneficial effect on the number of polyps in the small bowel and colon in patients with familial adenomatous polyposis (FAP). FAP is a rare gene defect that increases the risk of developing cancer of the intestines and colon. OCA is a drug similar to a bile acid the body makes. It is fluid made and released by the liver. OCA binds to a receptor in the intestine that is believed to have a positive effect on preventing cancer development. OCA has been effective in treating primary biliary cholangitis (PBC), a liver disease, and is approved by the Food and Drug Administration (FDA) for use at a lower dose (10 mg). There have been studies showing that OCA decreases inflammation and fibrosis. However, it is not yet known whether OCA works on reducing the number of polyps in patients with FAP.