A new experimental drug targeting a specific liver enzyme could offer the first direct treatment for metabolic dysfunction-associated steatohepatitis (MASH), a severe form of fatty liver disease that silently progresses in millions of people worldwide. Researchers at UC San Diego found that ION224, which blocks an enzyme called DGAT2, produced significant improvements in liver health during clinical trials, marking a potential breakthrough in treating a condition that currently has no approved medications.

What Is MASH and Why Should You Care?

MASH, formerly called nonalcoholic steatohepatitis (NASH), is a serious liver condition where excess fat accumulates inside liver cells, triggering inflammation and tissue damage. The disease is becoming increasingly common as obesity and type 2 diabetes rates climb globally. According to researchers, as many as one in four adults worldwide may have some form of fatty liver disease, with more than 100 million people in the United States affected.

The condition is particularly dangerous because most people never realize they have it. Symptoms often do not appear until serious liver damage has already developed. In severe cases, liver scarring can progress to cirrhosis and liver failure, leaving transplantation as one of the only remaining treatment options.

How Does ION224 Work Differently From Other Treatments?

ION224 takes a novel approach by targeting the root cause of liver fat accumulation rather than simply helping patients lose weight. The drug blocks DGAT2, an enzyme that helps the liver produce and store fat. Scientists believe that excess fat inside liver cells triggers inflammation, tissue damage, and scarring over time. By interrupting this process at its source, the drug may prevent the disease from progressing to life-threatening stages.

"By blocking DGAT2, we're interrupting the disease process at its root cause, stopping fat accumulation and inflammation right in the liver," said Rohit Loomba, principal investigator of the study and chief of the Division of Gastroenterology and Hepatology at UC San Diego School of Medicine.

Rohit Loomba, MD, Chief of Gastroenterology and Hepatology at UC San Diego School of Medicine

This approach is especially important because many current treatments for fatty liver disease mainly focus on weight loss. ION224 appeared to improve liver health even when patients did not lose significant weight, suggesting it may eventually work alongside popular GLP-1 (glucagon-like peptide-1) weight loss medications and other therapies.

What Did the Clinical Trial Show?

The Phase IIb clinical trial enrolled 160 adults in the United States with MASH and mild to moderate liver fibrosis. Participants received monthly injections of ION224 at different doses or a placebo over a 51-week period. The results were striking: about 60% of patients receiving the highest dose experienced meaningful improvements in liver health compared with those receiving placebo treatment.

Researchers also reported that the medication was generally well tolerated, with no serious side effects tied to the drug. The study is considered notable because it is the first to show that blocking DGAT2 with an antisense therapy can improve liver inflammation and fibrosis in people with MASH. The treatment also avoided some side effects seen with other drugs targeting liver fat production, including dangerous increases in triglycerides.

What Are the Key Factors That Drive Fatty Liver Disease?

Understanding what causes fatty liver disease can help people recognize their own risk. The condition develops when excess fat abnormally accumulates in the liver. When fat content exceeds 5% of the total liver weight, disruption of normal liver cell function occurs and inflammation begins.

• Processed and Refined Foods: Consuming too much processed and refined foods is the most common cause of fatty liver. Eating refined sugar in large amounts will turn to fat and be stored as triglycerides in the liver.
• Sugary Beverages and Sweets: Sugary drinks with high fructose corn syrup, candies, cookies, and desserts are among the worst offending foods for developing MASH, as they are quickly converted to liver fat.
• Refined Carbohydrates: White bread, white rice, and other baked goods, especially when consumed in large amounts, can cause fatty liver because they are usually low in fiber, rich in sugar, and have a high glycemic index.
• Saturated and Trans Fats: High fat foods, especially those rich in saturated fats like butter, cheese, cream, and processed meats can lead to fat deposition in the liver, as can trans fats found in margarines.
• Excess Alcohol: Alcohol, especially in excessive amounts of more than two or three drinks per day, contributes to fat accumulation in the liver because most alcohol is metabolized as sugar and converted to triglycerides.
• Obesity and Overweight: Being overweight and obese dramatically increases fat accumulation in the liver. Between 30% and 40% of North Americans have some degree of fatty liver, and 75% of people who are overweight with a body mass index (BMI) greater than 30 have it.

How Can You Support Your Liver Health?

While ION224 represents a major advance in treating MASH, dietary and lifestyle changes remain important for liver health. Research shows that with consistent and strict dietary and lifestyle modifications, fatty liver can be reversed, particularly in early stages.

Certain nutrients have been shown to support liver function and regeneration. Vitamins A, D, E, vitamin B3, and omega-3 oils can all be beneficial for liver health. Milk thistle, a plant that grows one to three meters in height with large prickly leaves and attractive red and purple flowers, has been used traditionally to support liver function. The active compounds in milk thistle, called silymarin, stabilize and strengthen liver cell membranes, prevent toxins from penetrating liver cells, increase the rate of protein synthesis to support liver cell regeneration, act as an antioxidant, and inhibit the production of damaging compounds.

What Happens Next for ION224?

The next step will be larger Phase III clinical trials designed to confirm the drug's safety and effectiveness in a broader patient population before regulators consider approval. Researchers are optimistic about the potential impact. "If these findings are confirmed in Phase III trials, we may finally be able to offer patients a targeted therapy that halts and potentially reverses liver damage before it progresses to life-threatening stages," Loomba noted.

The researchers also noted that future treatment strategies may involve combination therapies, pairing liver-targeted drugs like ION224 with medications that improve weight loss, insulin resistance, or metabolic health. This multi-pronged approach could offer patients more comprehensive protection against the progression of fatty liver disease.