Evaluation of HepQuant SHUNT to Assess Liver Disease; Substudy Within GS-US-416-2124

Inclusion Criteria

1. Willing and able to give informed consent prior to any study specific procedures being performed. In individuals with hepatic encephalopathy (HE) which may impair decision-making, consent will be obtained per hospital procedures (eg, by Legally Authorized Representative) 2. Clinical diagnosis of severe AH 3. Maddrey's DF ≥ 32 at screening

Exclusion Criteria

Key Exclusion Criteria: 1. Pregnant or lactating females; 2. Other causes of liver disease including chronic hepatitis B (hepatitis B surface antigen [HBsAg] positive), chronic hepatitis C (HCV RNA positive), acetaminophen hepatotoxicity, biliary obstruction, and autoimmune liver disease; 3. Serum AST >400 U/L or ALT >300 U/L; 4. MELD >30 at screening; 5. Maddrey's DF >60 at screening; 6. Grade 4 Hepatic Encephalopathy (HE) by West Haven criteria; 7. Concomitant or previous history of hepatocellular carcinoma; 8. History of liver transplantation; 9. HIV Ab positive; 10. Clinical suspicion of pneumonia; 11. Uncontrolled sepsis; 12. Uncontrolled gastrointestinal (GI) bleeding or controlled GI bleeding within 7 days of screening that was associated with shock or required transfusion of more than 3 units of blood; 13. Type 1 hepatorenal syndrome (HRS) or renal failure defined as a serum creatinine >221 μmol/L (>2.5 mg/dL) or the requirement for renal replacement therapy; 14. Individuals dependent on inotropic (eg, epinephrine or norepinephrine) or ventilatory support (ie, endotracheal intubation or positive-pressure ventilation); 15. Portal vein thrombosis; 16. Acute pancreatitis; 17. Cessation of alcohol consumption for more than 2 months before Baseline/ Day 1 NOTE: Other protocol defined Inclusion/ Exclusion criteria may apply.