Defibrotide for the Treatment of Severe Hepatic Veno-Occlusive Disease in Hematopoetic Stem Cell Transplant Patients

Inclusion Criteria: * Clinical diagnosis of VOD, defined by jaundice (bilirubin \>/= 2 mg/dL) and at least 2 of the following clinical findings, by Day+21 post stem cell transplant: ascites; weight gain \>/= 5% above baseline weight; hepatomegaly. * Severe VOD, defined as VOD with multi-organ failure, i.e., presence of one or both of the following, by Day+28 post stem cell transplant: renal or pulmonary dysfunction. * Provide voluntary written informed consent. Exclusion Criteria: * Pre-existing (prior to SCT) cirrhosis * An alternative diagnosis for weight gain, ascites and jaundice * Graft-versus-host disease (GVHD) grade B or higher involving liver or gut or grade C or higher involving skin * Prior solid organ transplant * Dependent on dialysis prior to and/or at the time of SCT * Dependent on oxygen supplementation prior to SCT * Significant acute bleeding or hemodynamic instability * Requirement for the use of any medications that increase risk of hemorrhage will be excluded from the treatment group