The aim of this study is to assess the safety and tolerability of EFX compared to placebo in subjects with non-invasively diagnosed NASH/MASH and NAFLD/MASLD.

Inclusion Criteria:

Main Study Only:

• Males and non-pregnant, non-lactating females between 18 - 80 (between 19-80 in the Republic 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 2 diabetes
• Suspected or confirmed diagnosis of NASH/MASH or NAFLD/MASLD or non-invasively diagnosed 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/or central laboratory results, including but not limited to: alcoholic liver disease, autoimmune disorders (e.g., primary biliary cholangitis [PBC], primary sclerosing cholangitis [PSC], autoimmune hepatitis), drug induced hepatotoxicity, Wilson disease, 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.