An update on novel pharmacological agents for primary sclerosing cholangitis.

INTRODUCTION: Primary sclerosing cholangitis (PSC) is a rare chronic cholestatic disease with heterogeneous phenotypes that may lead to liver transplantation and/or end-stage liver disease. Its multifactorial etiopathogenesis remains uncertain, but gut-liver axis and bile composition and excretion are widely demonstrated to influence the immune-mediated fibrogenic reactive cascade. AREAS COVERED: Different experimental therapeutic options are under investigation, mainly aiming at modulating bile acids excretion, limiting inflammatory-cascade reactions, and changing intestinal microbiota composition; none of them yet demonstrated to prolong transplant-free survival.This review provides a comprehensive description of the experimental drugs recently tested and/or currently under investigation. A bibliographical search was performed in PubMed, MEDLINE, EMBASE, OVID, and clinicaltrial.gov until July 2021. EXPERT OPINION: The heterogeneity and poor prevalence of PSC, its uncertain pathophysiology, and the lack of surrogate endpoints are the major challenges in drug discovery. Strategies that synergistically target microbiota, bile acids, and liver fibrosis are needed. In parallel, we must enhance biomarkers discovery to develop surrogate endpoints, as biochemical markers' fluctuations over the time hamper their effectiveness. Magnetic resonance cholangiopancreatography tools that accurately measure bile duct changes represent a potential marker for disease monitoring. A collaboration between academia, research consortia, patient's associations, and industry is required.