A Study Evaluating Efruxifermin in Subjects With Non-invasively Diagnosed Nonalcoholic Steatohepatitis (NASH)/Metabolic Dysfunction-Associated Steatohepatitis (MASH) and Nonalcoholic Fatty Liver Disease (NAFLD)/Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Inclusion Criteria:

Main Study Only:

• Males and non-pregnant, non-lactating females between 18 - 80 (between 19-80 in theRepublic of Korea) years of age inclusive, on the day of signing informed consent

• Previous history or presence of 2 out of 4 components of metabolic syndrome (obesity, dyslipidemia, elevated blood pressure, elevated fasting glucose) or type 2diabetes

• Suspected or confirmed diagnosis of NASH/MASH or NAFLD/MASLD or non-invasivelydiagnosed NASH/MASH or NAFLD/MASLD

Open-Label Rollover

• Prior participation in a previous Akero Phase 2 study

Exclusion Criteria:

• Other causes of liver disease based on medical history and/or liver histology and/orcentral laboratory results, including but not limited to: alcoholic liver disease,autoimmune disorders (e.g., primary biliary cholangitis [PBC], primary sclerosingcholangitis [PSC], autoimmune hepatitis), drug induced hepatotoxicity, Wilsondisease, clinically significant iron overload, or alpha-1-antitrypsin deficiency

• Type 1 or unstable Type 2 diabetes

A reduced list of inclusion and exclusion criteria apply to participants in the open-label rollover extension.

Other inclusion and exclusion criteria may apply.