Redox Modulation in Hepatic Fibrosis: Translating NOX1/4 Inhibition to Therapy.

Chronic liver disease (CLD) encompasses a spectrum of progressive disorders, including metabolic dysfunction steatotic-associated liver disease (MASLD) and primary biliary cholangitis (PBC), which together represent a significant global health burden with few effective therapeutic options. The fibrogenic process, common to most forms of CLD, is driven by a complex interplay of cellular stress, inflammation, and wound-healing responses. Nicotinamide adenine dinucleotide phosphate oxidase isoforms 1 and 4 (NOX1 and NOX4) have emerged as key enzymatic sources of reactive oxygen species (ROS), serving as central mediators of hepatic oxidative stress, fibrogenesis, and inflammation. Setanaxib is a first-in-class, orally bioavailable, selective dual inhibitor of NOX1 and NOX4 that has progressed to clinical evaluation. This review synthesizes current knowledge on the molecular pharmacology of the NOX1/4 axis, preclinical evidence from translational models, and clinical trial outcomes to critically assess the therapeutic potential of targeted NOX inhibition in hepatic fibrosis. By attenuating hepatic stellate cell activation, modulating TGF-β signaling, reducing extracellular matrix (ECM) deposition, and regulating hepatic macrophage polarization, setanaxib exhibits pleiotropic antifibrotic effects. The compound also demonstrates favorable pharmacokinetic properties and a good safety profile in patients with PBC, with emerging evidence suggesting meaningful improvements in fatigue and quality of life. Finally, we examine the complex, and sometimes paradoxical, roles of NOX4 in liver pathophysiology, compare the evolving therapeutic landscape with other approaches such as farnesoid X receptor (FXR) agonists, and propose future paradigms integrating artificial intelligence-driven predictive modeling to optimize patient stratification and therapeutic response in this new era of redox-targeted hepatoprotective therapy.