A Pivotal Clinical Study to Investigate Efimosfermin Alfa in Participants With Biopsy-confirmed F2- or F3-stage MASH

Prior treatment

• Chronic liver disease from any other cause including, but not limited to, alcoholic liver disease; evidence of portal hypertension; viral hepatitis or any history or evidence of cirrhosis on screening liver biopsy; or decompensated liver disease such as clinical ascites, bleeding gastroesophageal varices, hepatorenal syndrome, or hepatic encephalopathy prior to Screening or Day 1.
• Current or history of excessive alcohol intake for \>=3 months within the 12-month period prior to Screening

Other illness

• Model for End-Stage Liver Disease score \>=12 unless the score is elevated in the absence of liver dysfunction (e.g., Gilbert's syndrome)
• Evidence of infection with any of the following:
  • Human immunodeficiency virus;
  • Hepatitis B virus (detectable HBsAg at Screening);
  • Hepatitis C virus (HCV);

Lab values

• ALT or AST \>=5 x upper limit of normal (ULN)
• Total bilirubin \>=1.3 milligram per deciliter (mg/dL). Individuals with documented Gilbert's syndrome may be enrolled if they experienced an isolated increase in total bilirubin of \>=1.3 mg/dL and direct bilirubin is \<=20% of total bilirubin; otherwise, the individual will be excluded.
• Serum albumin \<=3.5 grams per deciliter (g/dL)
• International normalized ratio (INR) \>=1.3 not due to therapeutic anticoagulation. Individuals receiving chronic anticoagulant treatment with higher INR values may be enrolled at the discretion of the Investigator and Study Medical Monitor.
• Alkaline phosphatase (ALP) \>=2\*ULN
• Platelet (PLT) count \<140,000 per (/) cubic millimeter (mm\^3); individuals with a PLT count between 110,000/mm\^3 and 140,000/mm\^3 may be enrolled after discussion with the Study Medical Monitor.
• Serum creatinine \>=1.5 mg/dL or creatinine clearance \<=60 milliliter (mL)/minute (min)/1.73 square meter by Chronic Kidney Disease Epidemiology Collaboration equation
• Glycated hemoglobin \>=9.0%

Other

• Contraindication or ineligibility for percutaneous liver biopsy
• Alpha-fetoprotein \>=20 nanogram per milliliter (ng/mL)
• Phosphatidyl ethanol (PEth) \>=80 ng/mL at Screening

• Able and willing to understand and sign a written informed consent form that must be obtained prior to the initiation of study procedures
• Age \>=18 and \<=75 years at enrollment
• History or presence of 2 or more of the 5 components of metabolic syndrome per American Heart Association definition
• Liver biopsy confirmation of MASH consistent with stage F2 or F3 fibrosis and a NAS score \>=4 confirmed by a central pathologist