Metabolic dysfunction–associated steatotic liver disease (MASLD) has become the most common liver disease worldwide, with a global prevalence of 32.4%. Its growth over the past three decades has occurred in tandem with increasing rates of obesity and type 2 diabetes — two cornerstones of MASLD.
Higher rates of MASLD and metabolic dysfunction–associated steatohepatitis (MASH) with fibrosis are present in adults with obesity and diabetes, noted Arun Sanyal, MD, professor and director of the Stravitz-Sanyal Institute for Liver Disease and Metabolic Health, Virginia Commonwealth University, Richmond, Virginia.
The success surrounding the medications for obesity and type 2 diabetes, including glucagon-like peptide 1 receptor agonists (GLP-1 RAs), has sparked studies investigating whether they could also be an effective treatment for liver disease.
In particular, GLP-1 RAs help patients lose weight and/or control diabetes by mimicking the function of the gut hormone GLP-1, released in response to nutrient intake, and are able to increase insulin secretion and reduce glucagon secretion, delay gastric emptying, and reduce appetite and caloric intake.
The studies for MASLD are testing whether these functions will also work against liver disease, either directly or indirectly, through obesity and diabetes control. The early results are promising.
More Than One Risk Factor in Play
MASLD is defined by the presence of hepatic steatosis and at least one of five cardiometabolic risk factors: Overweight/obesity, hypertension, hyperglycemia, dyslipidemia with either low-plasma high-density lipoprotein cholesterol or high triglycerides, or treatment for these conditions.
It is a grim trajectory if the disease progresses to MASH, as the patient may accumulate hepatic fibrosis and go on to develop cirrhosis and/or hepatocellular carcinoma.
Typically, more than one risk factor is at play in MASLD, noted Adnan Said, MD, chief of the Division of Gastroenterology and Hepatology at the William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin.
“It most commonly occurs in the setting of weight gain and obesity, which are epidemics in the United States and worldwide, as well as the associated condition — metabolic syndrome — which goes along with obesity and includes type 2 diabetes, hyperlipidemia, hypertension, and sleep apnea,” Said, a hepatology and gastroenterology professor at the University of Wisconsin–Madison, told this news organization.
The research surrounding MASLD is investigating GLP-1 RAs as single agents and in combination with other drugs.
Finding treatment is critical, as there is only one drug — resmetirom — approved for the treatment of MASH with moderate to advanced fibrosis. But because it’s not approved for earlier stages, a treatment gap exists. The drug also doesn’t produce weight loss, which is key to treating MASLD. And while GLP-1 RAs help patients with the weight loss that is critical to MASLD, they are only approved by the US Food and Drug Administration (FDA) for obesity and type 2 diabetes.
Single Agents
The GLP-1 RAs liraglutide and semaglutide, both approved for diabetes and weight loss, are being studied as single agents against liver disease, Said said.
“Their action in the setting of MASLD and MASH is primarily indirect, through systemic pathways, improving these conditions via weight loss, as well as by improving insulin sensitivity and reducing lipotoxicity,” he added.
One of the first trials of these agents for liver disease was in 2016. In that double-blind, randomized, 48-week clinical trial of liraglutide in patients with MASH and overweight, 39% of patients who received liraglutide had a resolution of MASH compared with only 9% of those who received placebo. Moreover, only 9% vs 36% of patients in the treatment vs placebo group had progression of fibrosis.
Since then, a 72-week phase 2 trial in patients with MASH, liver fibrosis (stages F1-F3), and overweight or obesity found that once-daily subcutaneous semaglutide (0.1, 0.2, or 0.4 mg) outperformed placebo on MASH resolution without worsening of fibrosis (36%-59% vs 17%) and on weight loss (5%-13% vs 1%), with the greatest benefits at the largest dose. However, neoplasms were reported in 15% of patients receiving semaglutide vs 8% of those receiving placebo.
A phase 1 trial involving patients with liver stiffness, steatosis, and overweight or obesity found significantly greater reductions in liver fat at 48 weeks with semaglutide vs placebo, as well as decreases in liver enzymes, body weight, and A1c. There was no significant difference in liver stiffness.
Furthermore, a meta-analysis of eight studies found that treatment with 24 weeks of semaglutide significantly improved liver enzymes, reduced liver stiffness, and improved metabolic parameters in patients with MASLD/MASH. The authors cautioned that gastrointestinal adverse effects “could be a major concern.”
Several studies have found other GLP-1 RAs, including exenatide and dulaglutide, have a beneficial impact on liver injury indices and liver steatosis.
A new retrospective observational study offers evidence that GLP-1 RAs may have a direct impact on MASLD, independent of weight loss. Among the 28% of patients with type 2 diabetes and MASLD who received a GLP-1 RA, there was a significant reduction not only in body mass index but also in A1c, liver enzymes, and controlled attenuation parameter scores. A beneficial impact on liver parameters was observed even in patients who didn’t lose weight. While there was no difference in liver stiffness measurement, the median 60-month follow-up time may not have been long enough to capture such changes.
Another study indicated that the apparent benefits of GLP-1 RAs, in this case semaglutide, may not extend to patients whose disease has progressed to cirrhosis.