NR1H4 and primary biliary cholangitis: Obeticholic acid (OCA), an FXR agonist FDA-approved for primary biliary cholangitis (PBC) and nonalcoholic steatohepatitis (NASH), achieved histological improvement (≥1-stage fibrosis reduction without NASH worsening) in 22.4% of patients at 25 mg (vs. 9.6% placebo) over 18 months, with enhanced efficacy in F3-stage subgroups (25.4% vs. 12.3%) [88,89,90].