TReatment for ImmUne Mediated PathopHysiology

Pediatric Acute Liver Failure (PALF) is a rare, devastating condition that affects an estimated 250 children per year in North America, causing death in approximately 15% and the need for liver transplantation in an additional 20-30%. In the majority of cases, a specific cause of the liver injury is never determined. Recent research supports the theory that many of these patients have liver injury related to a hyperinflammatory immune response to everyday infections or environmental exposures. There is strong evidence to show that equine anti-thymocyte globulin and methylprednisolone slow the body's response to inflammation and improve the recovery of patients with other immune disorders and thus, may help patients with acute liver failure. This is a phase 2b, double-blind, three arm, randomized, placebo controlled trial with restricted response adaptive randomization. The primary objective is to determine the efficacy and safety of high-dose methylprednisolone or equine anti-thymocyte globulin (eATG or ATGAM®) as compared to supportive care alone (placebo) for the treatment of acute liver failure in pediatric patients. Approximately 160 patients who are equal to or greater than ≥ 1 and less than ≤ 18 years of age with pediatric acute liver failure (PALF) of undetermined etiology will be randomized to receive either high-dose methylprednisolone (Treatment 1) or eATG (ATGAM®) (Treatment 2) or supportive care alone (Treatment 3) on days 1 to 4 after study enrollment, followed by a gradual prednisolone taper (for the two active treatment arms 1 and 2) or a placebo taper (for treatment arm 3) on days 5 to 42. The follow-up period includes visits at 1 week (Day 7), 2 weeks (Day 14), and 3 weeks (Day 21) after the day the participant started in the study. Early follow-up assessments will be performed either in the inpatient or ambulatory setting since some participants may be discharged before Day 7. In addition, families will be contacted by phone or email to schedule each follow-up at the study site for the 6 week, 3 month, 6 month and 12 month study visits. This study includes a prospective observational cohort study of up to 50 patients with PALF who meet the randomized controlled trial (RCT) eligibility criteria and are willing to provide longitudinal observational data. The findings of this trial have the potential to shift the treatment paradigm in PALF and advance the basic understanding of immune dysregulation disorders in childhood. The network includes 20 of the largest and most active pediatric liver centers in the US who have organized to support rigorous testing of the efficacy and safety of immunosuppressive therapy for these patients. Recruitment into the randomized controlled trial stopped on February 17, 2026, but recruitment into the observational cohort will continue for about 6 months.