Umbilical Cord-derived Mesenchymal Stem Cell Infusion for Treating ACLF

Inclusion criteria

• Age between 18 and 70 years (inclusive) at the time of signing the informed consent form, regardless of gender.
• Patients with hepatitis B virus (HBV)-associated acute-on-chronic liver failure (ACLF) meeting the following criteria: Total bilirubin (TBil) ≥12 mg/dL (equivalent to 205 μmol/L); International normalized ratio (INR) ≥1.5 or prothrombin activity (PTA) ≤40%;
• All participants and their partners agree to use effective non-pharmacological contraception during the trial and for 6 months after trial completion, with no plans for conception during this period.
• Voluntarily participate in the clinical study and sign the informed consent form.

Exclusion criteria

• History of allergy to any component of the investigational drug or bovine-derived products.
• Acute, subacute, or chronic liver failure unrelated to HBV, or ACLF caused by: Concurrent hepatitis A, C, or E virus infection; Autoimmune liver disease; Biliary obstruction.
• Presence of any of the following complications: <1> Active gastrointestinal bleeding (e.g., hematemesis and/or melena) or high- risk esophageal/gastric varices (confirmed by endoscopy or imaging within 3 months prior to screening). <2> Imaging evidence (ultrasound or CT) of cavernous transformation of the portal vein or portal vein occlusion. <3> History of transjugular intrahepatic portosystemic shunt (TIPS). <4> Grade 3 or 4 hepatic encephalopathy. <5> Serum creatinine ≥2 mg/dL. <6> Respiratory insufficiency (e.g., dyspnea, cyanosis) with peripheral oxygen saturation ≤93% at rest.
• Severe underlying diseases, including: <1>Septic shock (requiring vasopressors to maintain mean arterial pressure ≥65 mmHg despite adequate fluid resuscitation, with blood lactate >2 mmol/L). <2> Uncontrolled cardiac conditions: Myocardial ischemia or infarction (CTCAE v5.0 Grade ≥II), Arrhythmias requiring intervention, NYHA Class III-IV heart failure. <3> Active malignancy (solid or hematologic). <4> Diagnosed pulmonary hypertension or suspected pulmonary embolism. <5> IgA deficiency, Henoch-Schönlein purpura, hemophilia, or idiopathic thrombocytopenia. <6> Immunodeficiency disorders (e.g., HIV infection, congenital/acquired immune deficiency).
• Current systemic corticosteroid therapy for other diseases.
• Psychiatric or other conditions deemed by the investigator to interfere with study assessments.
• Planned or active registration for liver transplantation, or anticipated transplantation within 3 months.
• History of liver transplantation.
• Alcohol or substance abuse: Chronic alcohol use (>5 years with ethanol intake ≥40 g/day for males or ≥20 g/day for females), Heavy alcohol use (>80 g/day ethanol) within 2 weeks prior to screening, Abstinence <6 months.
• Participation in another clinical trial within 3 months prior to screening (excluding screen failures or withdrawal before dosing).
• Pregnancy, lactation, or positive pregnancy test at screening.
• Any other condition that, in the investigator's judgment, may confound study results, pose risks, or compromise the participant's best interests.