FDA Approves First MASH Treatment

The Food and Drug Administration (FDA) has approved the first-ever medication for a common form of liver disease called non-alcoholic steatohepatitis (NASH).

NASH, more recently known as metabolic dysfunction-associated steatohepatitis (MASH), is an advanced type of liver disease where fat builds up in the liver, causing inflammation and cell damage.

Approximately 6 to 8 million Americans have MASH, accompanied by some level of liver scarring (fibrosis). Without proper management, MASH can escalate into permanent liver scarring (cirrhosis), liver failure, or liver cancer.

Rezdiffra (resmetirom), developed by Madrigal Pharmaceuticals, is a daily oral pill that can activate a thyroid hormone receptor in the liver to reduce fat build-up. It’s approved for adults with NASH who have moderate to advanced liver scarring and is to be used along with diet and exercise.

Prior to this approval, there was no medication for MASH. The only recommended treatments were gradual weight loss and lifestyle changes.

“We have a new tool that allows us to help get rid of fat in the liver and maybe also reverse liver damage. We consider this groundbreaking and a major breakthrough in the treatment of this condition that often goes ignored,” Sammy Saab, MD, MPH, a hepatologist and medical director of the Pfleger Liver Institute at UCLA Health, told Verywell.

Saab has advised Madrigal Pharmaceuticals in the past but was not involved with the development of Rezdiffra.

How Effective Is Rezdiffra?

Healthcare providers sometimes recommend vitamin E and the diabetes drug pioglitazone for people with MASH, but these don’t help improve scar tissue in the liver, according to Vivek Mendiratta, MD, a gastroenterologist, transplant hepatologist, and clinical assistant professor of internal medicine at The Ohio State University Wexner Medical Center.

“This medication is very exciting, but it definitely doesn’t replace the need and necessity for lifestyle changes for improvement in steatotic liver disease,” Mendiratta told Verywell.

An ongoing phase 3 clinical trial showed that about 24%–36% of participants who received 100 milligrams of Rezdiffra experienced MASH resolution and no worsening of liver scarring, compared to 9% to 13% of those who received placebo and counseling on diet and exercise.

The company will need to complete a post-approval study after approval to verify the anticipated clinical benefit, according to an FDA spokesperson.

What Are the Side Effects of Rezdiffra?

Some people may experience side effects such as nausea, diarrhea, stomach pain, vomiting, itching, diarrhea, dizziness, and constipation when taking Rezdiffra. It can also lead to liver injury and gallbladder problems in severe cases and can interfere with certain drugs, such as statins, for lowering cholesterol.

“Very few people suffer side effects. It’s very well tolerated,” Saab said.

The medication is promising, but providers still need guidance on how to use it in clinical practice before it is available in April, Saab added.

A Madrigal spokesperson told Verywell in an email that they expect most patients to continue with “long-term Rezdiffra treatment as their disease improves,” but each patient is unique, and the physician and patient will decide together when to continue or halt therapy.

Questions remain about insurance coverage and costs for patients. However, Mendiratta is optimistic and expects patients will want to try it once it is available.

“Our patients have wanted a medication for a long period of time and have been searching for a long period of time,” Mendiratta said. “They’re excited about this medication and probably will want to jump on as soon as possible if given the chance.”