NASH stands for Non-Alcoholic Steatohepatitis, a liver condition caused by fat buildup. This study tests a medicine called GSK4532990 to see if it helps improve liver fibrosis (scarring) and inflammation in people with advanced NASH. Participants will take either the medicine or a placebo (a fake pill) to compare results. The whole study lasts up to 76 weeks, including 52 weeks of treatment.

Eligibility: To join, you need a Body Mass Index (BMI) of at least 25 (23 for Asians), and your liver condition should mostly be due to NASH. You must also have features of a condition called metabolic syndrome, which includes problems like type 2 diabetes, obesity, or high blood pressure. Before starting, you'll need a liver biopsy, a test to check your liver's condition.

• Study lasts for 76 weeks with 52 weeks of treatment.
• Participants must agree to a liver biopsy at the start and after 52 weeks.
• Participants should not have had weight reduction surgery in the past 2 years.