Medical breakthroughs rarely follow a straight line. Often, they happen in the periphery—a side effect noticed during a trial for something else, or a pattern emerging from data that was meant to answer a different question. For researchers at the Medical University of South Carolina (MUSC), the potential for a new liver disease treatment began not with a liver, but with a kidney.
While investigating ways to mitigate kidney damage in patients with diabetes, a team of scientists discovered that a common, decades-old asthma medication was doing something unexpected: it was clearing fat from the livers of their test subjects. This serendipitous finding has led to a new line of inquiry into formoterol, a beta-2 adrenergic receptor agonist, as a potential therapy for metabolic dysfunction-associated steatohepatitis (MASH).
MASH is a severe form of fatty liver disease characterized by inflammation and liver cell damage. It’s a silent but progressive condition that affects hundreds of millions of people globally and stands as a leading cause of liver transplantation. For years, the medical community has struggled to find treatments that do more than simply slow the progression of the disease. The discovery that a repurposed drug might actually reverse existing damage offers a promising new direction for public health.
The Serendipity of a “Two-for-One” Discovery
The journey toward this discovery began with a study on diabetic nephropathy—kidney disease caused by diabetes. The research team, led by Joshua Lipschutz, M.D., Division Director of Nephrology and the Arthur Williams Endowed Chair in Nephrology at MUSC, was testing formoterol in mouse models to see if it could protect kidney function. The results were successful and published in the American Journal of Physiology, Renal Physiology in 2024.
However, upon examining the mice, the researchers noticed a striking anomaly: the animals receiving formoterol had significantly less liver fat and reduced liver damage compared to the control group. This unexpected outcome suggested that the beta-2 adrenergic pathway, which formoterol activates to open airways in asthma and COPD patients, might have a systemic metabolic effect that transcends the respiratory system.
Intrigued, the team launched a second, targeted study using a high-fat diet mouse model specifically designed to mimic the pathology of MASH. The results were definitive. Treatment with formoterol didn’t just stop the accumulation of fat; it reversed the pathology at histologic, ultrastructural, and functional levels.
Reving Up the Mitochondria
To understand why a lung medication would impact the liver, researchers looked at the cellular level. They found that formoterol appeared to stimulate “mitochondrial biogenesis”—essentially the creation of new mitochondria, the powerhouses of the cell.
In MASH, the liver’s ability to process energy is compromised, leading to the accumulation of fat and subsequent inflammation. By “revving up” the mitochondria, formoterol helps the cells produce and use energy more efficiently, which in turn helps the liver clear excess fat and repair damaged tissue. This mechanism is distinct from many current metabolic treatments that focus primarily on weight loss or glucose regulation.
The researchers also sought to validate these animal findings with real-world human data. They conducted a retrospective analysis of patients already prescribed beta-2 agonists for respiratory conditions. The data revealed a compelling association: patients using these medications had significantly lower rates of serious liver-related complications, including cirrhosis and all-cause mortality.
A New Landscape for MASH Treatment
The urgency of this research is underscored by the rising global prevalence of obesity and Type 2 diabetes, both of which are primary drivers of MASH. Until recently, there were no FDA-approved medications specifically for MASH, leaving clinicians to rely on lifestyle interventions and the management of underlying comorbidities.
While newer therapies have entered the market, the need for more effective, accessible options remains high. The following table compares the current therapeutic landscape with the potential role of formoterol:
| Treatment Type | Primary Mechanism | Current Status/Effect |
|---|---|---|
| Current Approved Therapies | Targeting liver markers/weight loss | Moderately effective; primarily slow progression |
| Standard Care | Diet and exercise | Difficult for long-term adherence in severe cases |
| Formoterol (Experimental) | Mitochondrial biogenesis | Shows potential to reverse histologic damage |
One of the most significant advantages of formoterol is its existing safety profile. Because it has been prescribed for asthma and COPD for decades, it is already well-understood by clinicians and regulatory bodies. Repurposing an existing drug can drastically shorten the timeline for clinical development compared to creating a new molecule from scratch.
The Road to Human Trials
Despite the promising data, the transition from mouse models to human patients is a rigorous process. Dr. Lipschutz and his team are mindful of the limitations of their current findings. Observational human data shows an association, but it does not prove causation, and the primary physiological evidence currently rests on animal models.
We find also practical pharmacological questions to answer. Researchers must determine the optimal dosage for metabolic treatment and whether the drug should be delivered via inhalation—as it is for asthma—or through another method to ensure it reaches the liver and kidneys in sufficient concentrations.
Currently, the team is enrolling patients in a clinical trial focusing on diabetic kidney disease. Because more than 60% of patients with diabetic nephropathy also suffer from MASH, this trial serves as a “two-for-one” study. It will allow investigators to simultaneously monitor the drug’s effect on both the kidneys and the liver, addressing two of the most life-threatening complications of diabetes in a single cohort.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Please consult a healthcare provider before making any changes to your medication or treatment plan.
The next critical milestone for this research will be the release of data from the ongoing clinical trial involving patients with diabetic kidney disease. These results will determine if the reversal of liver pathology seen in the lab can be replicated in humans, potentially opening the door for a new, inexpensive, and safe treatment for millions of people living with MASH.
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