Dose Exploration Study of GSK4532990 in. Participants With NASH or Suspected NASH

Inclusion Criteria: * Participant must be 18 to 75 years of age. * Participant must be capable of giving signed informed consent which includes compliance with the requirements and restrictions listed for the study. * Participants who have proven diagnosis of NASH or suspected NASH based on defined study criteria. * Participants must meet predefined stable use requirements of concomitant medications based on study criteria. Exclusion Criteria: Individuals who meet any of the following exclusion criteria will not be eligible to participate in the study: * Cirrhosis or current unstable liver or biliary disease. * Other causes of liver disease including, but not limited to, alcohol-related liver disease, autoimmune disorders. * Known weight loss of ≥5% within 3 months prior to Screening. * Weight reduction surgery or procedures within 2 years of Screening. * Any contraindication to undergoing liver biopsy. * Any contraindication to undergoing Magnetic Resonance Imaging or FibroScan®.