This is a Phase 1, first-in-human (FIH) safety, proof-of-concept, two-part study of the genetically-engineered EGEN-5784 liver in combination with the metra® extra-corporeal liver cross-circulation (ELC) system in participants with Grade 2 to Grade 3 acute-on-chronic liver failure (ACLF) and hepatic encephalopathy Grade 1-3. The metra® device has been modified for the purposes of cross-circulation with an extra-corporeal porcine liver. The EGEN-5784 liver and metra® ELC device are designed to support liver function during the treatment period

This is a Phase 1, first-in-human (FIH) safety, proof-of-concept, two-part study of the genetically engineered EGEN-5784 liver in combination with the metra® extra-corporeal liver cross-circulation (ELC) system in participants with Grade 2 to Grade 3 acute-on-chronic liver failure (ACLF) and hepatic encephalopathy Grade 1-3. The metra® device has been modified for the purposes of cross-circulation with an extra-corporeal porcine liver. The EGEN-5784 liver and metra® ELC device are designed to support liver function during the treatment period

In Part 1, up to 6 participants will be enrolled and undergo ELC for up to 2 centers in the US.

In Part 2, up to 14 participants will be enrolled and undergo ELC at approximately 8 centers in the US.

The study will assess the safety of the ELC used to support liver function in patients with acute on chronic liver failure. Safety will be assessed based on Adverse Events Serious Adverse Events during the 28 days post-ELC and for the duration of the study. Unanticipated adverse device effects will be assessed during the ELC. Liver-related laboratory parameters will be assessed during the ELC treatment, and during the follow up period.

Key Inclusion Criteria:

• Male or female, age 18 to 70 years, inclusive
• Not eligible for transplantation at the time of enrollment
• Diagnosis of Grade 2 to 3 ACLF according to the European Association for the Study of Chronic Liver Failure (EASL-CLIF) definition and Chronic Liver Failure Consortium-organ failure score (CLIF-C-OF) ≥10
• Hepatic encephalopathy Grade 1 to 3 by West Haven Criteria
• Written consent provided by participant or LAR (if participant lacks capacity, e.g., due to hepatic encephalopathy) prior to conduct of any study procedures

Key Exclusion Criteria:

• Prior solid organ transplant
• Fulminant hepatic failure without underlying liver disease
• Non-biological artificial liver extracorporeal liver support (e.g., molecular adsorbent recirculating system) or bioartificial liver support systems within 30 days prior to EGEN-5784 liver perfusion
• Liver dysfunction due to trauma, or extra-hepatic cholestasis
• Any uncontrolled ongoing active infection
• History or active human immunodeficiency virus (HIV) infection or acute hepatitis B virus (HBV)
• Chronic HBV or active hepatitis C
• Diagnosis of cancer requiring active ongoing treatment, e.g., chemotherapy, radiation therapy
• Severe concomitant cardiovascular disease defined as congestive heart failure Class III and IV
• Significant acute or chronic pulmonary disease requiring ventilator support or diagnosed with chronic obstructive pulmonary disease Global Obstructive Lung Disease [GOLD] stage III or IV disorder
• Active uncontrolled bleeding (i.e., any major blood loss requiring ≥2 units of pRBCs within the last 48 hours prior to screening)
• Any other health condition, including illicit drug use, that would preclude participation in the study in the judgement of the PI