NR1H4 and primary biliary cholangitis: On the other hand, after the discovery of obeticholic acid (6α-ethyl-chenodeoxycholic acid, OCA, INT-747), the first-in-class FXR ligand (Pellicciari et al., 2002) approved for the treatment of resistant primary biliary cholangitis (PBC), the structural modifications of BAs have been intensively focused on the development of selective or dual FXR and GPBAR1 agonists (Fiorucci et al., 2019; Ratziu et al., 2019).