The US Food and Drug Administration has given its approval for the first medication designed to treat a common form of liver inflammation known as nonalcoholic steatohepatitis (NASH). This approval marks a significant milestone in the treatment of NASH, a condition that affects an estimated 6 to 8 million people in the US.

NASH, also referred to as metabolic dysfunction-associated steatohepatitis (MASH), is characterized by liver inflammation due to an excess of fat cells, representing an advanced form of nonalcoholic fatty liver disease. Complications associated with NASH include cirrhosis, liver failure, and liver cancer.

Prior treatment approaches for NASH focused on lifestyle changes such as weight loss through blood sugar control, a healthy diet, and regular exercise. However, the newly approved medication, developed by Madrigal Pharmaceuticals and marketed under the name Rezdiffra, offers a groundbreaking solution for individuals with moderate to advanced fibrosis resulting from NASH.

The medication, resmetirom, received Breakthrough Therapy designation from the FDA, expediting its development and review process due to its potential to significantly improve available therapies. Resmetirom, which works by activating a thyroid hormone receptor in the liver to reduce fat accumulation, is intended for daily oral consumption alongside a healthy diet and exercise regimen.

Clinical trial results published in February demonstrated promising outcomes, with over 25% of participants taking 80 milligrams of resmetirom achieving NASH resolution without fibrosis worsening, along with additional benefits such as lowered LDL cholesterol levels and liver enzyme levels. Most adverse events reported during the trial were mild or moderate, with common side effects including diarrhea and nausea.

However, it is important to note that Rezdiffra may have significant interactions with certain other drugs, particularly statins used to lower cholesterol. As a result, the FDA has emphasized the need for a post-approval study to verify the clinical benefits of the medication.

This approval has been met with optimism from the NASH community, with Wayne Eskridge, CEO of the Fatty Liver Foundation, expressing belief that it will invigorate efforts to enhance disease education, develop care pathways, and expand investment in NASH research.