NR1H4 and biliary liver cirrhosis: Obeticholic acid (OCA), a semisynthetic derivative of chenodeoxycholic acid (CDCA), initially named 6-ethyl-CDCA or INT-747, is the first in a class of FXR ligands that have been approved for clinical use for the treatment of patients with primary biliary cholangitis (PBC) who are unresponsive or intolerant to ursodeoxycholic acid.