That's the key question in hepatology right now. The general principle is that fibrosis up to F3 (bridging fibrosis) is potentially reversible given sufficient stimulus. F4 (cirrhosis) has traditionally been considered irreversible, though there is emerging evidence that early cirrhosis can regress with sustained intervention.
For GLP-1 RAs specifically, the most robust data is in F1-F3 fibrosis. Patients with compensated cirrhosis (F4, Child-Pugh A) were included in some trials, but the numbers are small and the results are mixed. Importantly, GLP-1 RAs should be used with caution in decompensated cirrhosis (ascites, varices, encephalopathy) due to altered drug metabolism and the risk of aspiration with delayed gastric emptying.
For most MASH patients with F2-F3 fibrosis — which is where the greatest clinical urgency lies, as these patients are at highest risk of progression to cirrhosis — the data is very encouraging. Early, aggressive treatment with GLP-1 agonists may prevent the need for liver transplantation in some patients.