NR1H4 and primary biliary cholangitis: To what extend patients with PBC are profiting from an UDCA-pretreatment on top of e.g. the synthetic FXR ligand obeticholic acid (OCA) remains elusive, but synergistic treatment mechanisms may explain the significant additional efficacy seen when OCA or a low dose of a nonsteroidal FXR agonist was combined with UDCA [53–55].