Semaglutide Reversed Fatty Liver Disease in 59% of Patients — But Didn't Fix the Scarring

72-week, double-blind, placebo-controlled phase 2 trial. 320 patients with biopsy-confirmed NASH and fibrosis (F1-F3) were randomized 3:3:3:1:1:1 to semaglutide 0.1, 0.2, or 0.4 mg daily or corresponding placebo via subcutaneous injection. Primary endpoint: NASH resolution without fibrosis worsening, assessed by paired liver biopsies. Confirmatory secondary endpoint: improvement of at least one fibrosis stage without NASH worsening. Endpoint analyses for these outcomes were restricted to the 230 patients with F2-F3 fibrosis.

This was the first major RCT to test semaglutide specifically for NASH/MASH, published in the world's most prestigious medical journal. The 59% NASH resolution rate at 0.4 mg daily was striking — but the failure to significantly improve fibrosis is the critical limitation, because fibrosis stage is the strongest predictor of liver-related death. This result helped shape the field's understanding that GLP-1 drugs alone may not be enough for advanced liver disease, motivating combination approaches (like adding efruxifermin or resmetirom).

This trial established semaglutide as a potential treatment for NASH/MASH but also exposed its limitation — it can resolve liver inflammation but may not adequately address fibrosis on its own. This finding was pivotal in driving the field toward combination therapies, pairing GLP-1 drugs with liver-targeted agents like resmetirom (now FDA-approved as Rezdiffra) or FGF21 analogs like efruxifermin. The study also highlighted the profound impact of GLP-1-mediated weight loss on liver health.

Phase 2 trial with 320 patients — adequately powered for the primary endpoint but may be underpowered for fibrosis improvement detection. The semaglutide doses (0.1-0.4 mg daily) differ from the approved weight-loss dose (2.4 mg weekly as Wegovy), making direct comparisons with current clinical practice difficult. The 72-week duration may be insufficient to show fibrosis reversal, which is a slow process. The small neoplasm signal warrants monitoring in larger trials. Daily subcutaneous dosing is more burdensome than the once-weekly formulation used clinically.