ESSENCE Trial: Semaglutide Resolved Fatty Liver Disease in 62.9% of Patients

Metabolic dysfunction-associated steatohepatitis (MASH) affects roughly 1 in 20 Americans and can progress to cirrhosis, liver cancer, and death. The Phase 3 ESSENCE trial is the first to show a GLP-1 drug can reverse the liver damage — not just slow it down. The FDA granted Wegovy Priority Review for this indication in 2025.

MASH — formerly called NASH — is the aggressive form of fatty liver disease that drives fibrosis, cirrhosis, and liver failure. Until 2024, there were no FDA-approved treatments. Then resmetirom (Rezdiffra) became the first. Now semaglutide is positioned to become the second, with Phase 3 data that approaches the disease from an entirely different angle: rather than targeting the liver directly, semaglutide appears to resolve MASH by correcting the underlying metabolic dysfunction that causes it.

The ESSENCE trial results, published in the New England Journal of Medicine on April 30, 2025, showed that 62.9% of patients treated with semaglutide 2.4 mg achieved complete resolution of steatohepatitis with no worsening of liver fibrosis — nearly double the placebo rate. The FDA accepted Novo Nordisk's application for this indication and granted Priority Review.

What ESSENCE Tested

ESSENCE (NCT04822181) is a multicenter, randomized, double-blind, placebo-controlled Phase 3 trial enrolling adults with biopsy-confirmed MASH and moderate to advanced liver fibrosis (stage F2 or F3 on the NASH CRN fibrosis scale). The trial compares once-weekly subcutaneous semaglutide 2.4 mg against placebo. The NEJM publication reports the planned interim analysis at 72 weeks involving the first 800 patients (534 semaglutide, 266 placebo).

The trial has two co-primary endpoints: resolution of steatohepatitis without worsening fibrosis, and improvement of liver fibrosis by at least one stage without worsening steatohepatitis. Both are assessed by liver biopsy — the gold standard for MASH evaluation, and a demanding endpoint because it requires physical tissue evidence, not just blood markers or imaging.

Primary and Secondary Results

Both co-primary endpoints were met with statistical significance. The 28.7-percentage-point difference in MASH resolution is clinically substantial. Importantly, semaglutide also produced improvements across noninvasive liver markers that aligned with the histological findings, reinforcing that the biopsy results reflect genuine disease modification.

Cardiometabolic improvements were also observed: reductions in blood pressure, HbA1c, and triglycerides — consistent with semaglutide's effects in obesity and diabetes trials (STEP-1, SELECT, SOUL).

How It Works Without Liver Receptors

Here's the counterintuitive part: GLP-1 receptors are not expressed in the liver. Semaglutide does not act directly on liver cells. Instead, its therapeutic effect on MASH is mediated indirectly through its actions on the brain (appetite suppression, reduced caloric intake), the gastrointestinal tract (slowed gastric emptying), adipose tissue (reduced visceral fat), and the pancreas (improved insulin sensitivity). By correcting the systemic metabolic dysfunction — obesity, insulin resistance, chronic inflammation — that drives fat accumulation and inflammation in the liver, semaglutide resolves the hepatic disease downstream.

This distinguishes semaglutide from resmetirom, which directly targets the thyroid hormone receptor beta in the liver. The two drugs attack MASH through fundamentally different mechanisms, which raises the possibility that combination therapy could eventually prove more effective than either drug alone.

Safety in Liver Disease Patients

No new safety signals emerged in this MASH population. There were no signals of drug-induced liver injury — a critical finding given that patients with advanced liver fibrosis may metabolize drugs differently. Deaths were numerically lower in the semaglutide group (3) than placebo (6) among the first 800 patients. The adverse event profile was consistent with semaglutide's established safety data: GI side effects (nausea, diarrhea, constipation) were most common, predominantly during dose escalation.

The Competitive Landscape

Resmetirom (Rezdiffra) was approved in March 2024 as the first MASH therapy. Tirzepatide is being studied in MASH via the SYNERGY-NASH program. Retatrutide's Phase 2a showed striking liver fat reduction (82.4% at the highest dose). Survodutide and pemvidutide are also in development for liver-related endpoints. Semaglutide's potential advantage is its established safety record across large cardiovascular and obesity trials, and the fact that it simultaneously treats the metabolic comorbidities (obesity, diabetes, cardiovascular risk) that MASH patients almost universally carry.

The AASLD published updated Practice Guidance in 2025 acknowledging semaglutide's role in MASH management. If FDA approval follows the Priority Review, clinicians will have a choice between a liver-targeted drug (resmetirom) and a metabolic-disease drug (semaglutide) — or potentially both.