Immunosuppression Withdrawal for Stable Pediatric Liver Transplant Recipients

Inclusion Criteria: * Subject and/or parent guardian must be able to understand and provide informed consent; * Is the recipient of a living or deceased donor liver tx when subject was less than or equal to 6 years of age; * Is at least 4 years post-tx at the time of study enrollment; * Has normal allograft function defined as Alanine aminotransferase (ALT) \< 50 IU/l and gamma-glutamyl transferase (GGT) \< 50 IU/l; * Has no evidence of acute rejection (AR) or chronic rejection (CR) within the past 2 years, based on medical history; * Is stable on IS monotherapy with a calcineurin inhibitor (CNI); * For female subjects of childbearing potential, subject must have a negative pregnancy test upon study entry; * For female and male subjects with reproductive potential, subject must agree to use FDA approved methods of birth control for the duration of the study; * Must be negative for hepatitis B virus (HBV) and hepatitis C virus (HCV) infection within one year of enrollment; * Must have screening biopsy that fulfills, based on central pathology reading, the following criteria: * Portal inflammation and interface activity: Preferably absent, but minimal to focal mild portal mononuclear inflammation may be present. Interface necro-inflammatory activity is absent or equivocal/minimal and, if present, involves a minority of portal tracts. * Centrizonal/peri-venular inflammation: Preferably absent, but minimal to focal mild perivenular mononuclear inflammation may be present. P…