The new era of MASH pharmacotherapy: a comprehensive review of FDA-approved and emerging agents.

BACKGROUND: Metabolic dysfunction-associated steatohepatitis (MASH), formerly nonalcoholic steatohepatitis (NASH), is a progressive liver disease and a leading cause of cirrhosis and liver-related mortality worldwide, affecting approximately 3%-5% of the global adult population and up to 30%-40% of individuals with type 2 diabetes mellitus (T2DM) or those attending dedicated diabetes and endocrine centers. For decades, treatment was limited to lifestyle interventions. The years 2024 and 2025 marked a paradigm shift with the first-ever FDA approvals of pharmacologic agents for MASH. SCOPE: This comprehensive narrative review synthesizes the evidence for newly approved and emerging pharmacotherapies for MASH, addressing the mechanisms of action, pivotal clinical trial data, efficacy, safety profiles, and place in therapy for resmetirom and semaglutide. It also discusses key agents including pioglitazone, saroglitazar, and vitamin E, and evaluates the non-invasive testing (NIT) toolkit-including FIB-4, VCTE, shear wave elastography, MRE, and ELF-in the context of a structured, risk-stratified clinical algorithm. FINDINGS: Resmetirom (Rezdiffra), a THR-β agonist, achieved MASH resolution in 26%-30% versus 10% placebo and fibrosis improvement in 24%-26% versus 14% placebo at 52 weeks in the MAESTRO-NASH trial. Semaglutide 2.4 mg (Wegovy) demonstrated a 28.7% delta over placebo in MASH resolution in the ESSENCE trial. Pioglitazone has additional evidence for reducing the FIB-4 index in real-world studies. Saroglitazar, a PPAR-α/γ dual agonist approved in India, has shown significant reductions in ALT, liver fat, and metabolic parameters in Phase 2 studies and is advancing to Phase 2b. Shear wave elastography is a clinically important alternative to VCTE for fibrosis staging, particularly in patients with obesity, and offers value in resolving discordant FIB-4/VCTE results. CONCLUSION: The approval of resmetirom and semaglutide marks a new era in MASH management. A risk-stratified algorithmic approach using NITs guides patient selection, with liver biopsy reserved for specific clinical scenarios. The therapeutic landscape is rapidly evolving, with saroglitazar and combination approaches representing key frontiers.