This study examines the effectiveness of resmetirom (also known as MGL-3196) in treating people with Non-Alcoholic Steatohepatitis (NASH), a serious liver condition where fat buildup leads to inflammation and liver damage. NASH occurs when the liver becomes inflamed due to fat accumulation, which can lead to scarring of liver tissue (known as fibrosis) and potentially progress to more severe liver damage.

The study medication resmetirom is taken as a film-coated tablet by mouth once daily. Participants will receive either resmetirom at doses of 60 mg, 80 mg, or 100 mg, or a placebo. The study aims to determine if resmetirom can help resolve NASH and prevent the progression of liver damage. The treatment period lasts for approximately 54 months, during which participants will have regular check-ups to monitor their liver health.

Throughout the study, doctors will use various methods to assess how well the treatment is working, including examining liver tissue samples and using specialized imaging called MRI-PDFF to measure liver fat content. They will also monitor the levels of various substances in the blood that can indicate liver health and track any changes in LDL cholesterol levels. After the main study period, some participants may have the opportunity to continue treatment in a long-term extension phase.