Defibrotide Therapy for SARS-CoV2 (COVID-19) Acute Respiratory Distress Syndrome (ARDS)

Inclusion Criteria: * Presence of SARS-CoV2 infection, confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR) assay from a nasopharyngeal swab specimen or other diagnostic test for SARS-CoV2. * Serum D-Dimer ≥ 2.0 mcg/ml. * Patients with Acute Respiratory Distress Syndrome (ARDS) as determined by the following criteria (Berlin criteria adaptation): * Radiographic evidence of bilateral lung disease (opacities or ground glass opacification) on chest radiograph (CXR) or computed tomography (CT), and the opacities not fully explained by pleural effusions, cardiac failure or fluid overload. * Impairment of oxygenation, as defined by the ratio of arterial oxygen tension to fraction of inspired oxygen (PaO2/FiO2) ≤ 300 mmHg (millimeters of mercury). * Patients must provide voluntary written informed consent to be eligible for study. For patients who are medically unable to provide consent, their designated proxy or legal guardian will provide informed consent. The consenting process is described in Appendix II. * Patients actively participating in another clinical trial for the management of SARS-CoV2 are eligible provided those trials do not directly involve an anti-platelet, anti-coagulant or anti-fibrinolytic agent. (Patients enrolled on investigational trials utilizing anti-viral specific agents, cytokine inhibitors, tyrosine kinase inhibitors, or other anti-inflammatory agents are still eligible). Exclusion Criteria: * Concomitant use of heparin, systemic anticoagulants, and/or fibrinolytics are not permitted within 12 hours, with the exception of heparin flushes for centrally placed catheters, fibrinolytic instillation for central venous line occlusion, or in the in-flow circuit for patients on continuous veno-venous hemodialysis. * Clinically significant acute bleeding, including (but not limited to one of the following): pulmonary hemorrhage (diffuse alveolar hemorrhage), intracranial bleed, gastro-intestinal hemorrhage (gross hematemesis or hematochezia), gross hematuria or uncontrolled epistaxis irrespective of the amount of blood loss, within the prior 3 days. * On mechanical ventilation for \> 96 consecutive hours. * Serum platelet count \< 50,000/Microliters (uL). Transfusion of platelets to achieve a level \> 50,000/uL is not allowed for eligibility. * Serum fibrinogen \< 150 mg/dl. Transfusion of fresh frozen plasma or cryoprecipitate to achieve a level \> 150 mg/dl is not allowed for eligibility. * Positive blood culture for a bacterial pathogen within the prior 24 hours prior to study entry, and/or the presence of bacterial pneumonia. * Hemodynamic instability as defined by a requirement for 2 or more vasopressors (not including renal-doses of dopamine). * Concurrent use of Extracorporeal membrane oxygenation (ECMO). * Patients with a previously known hypersensitivity reaction to defibrotide, or any of its excipients. * Females who are pregnant or breastfeeding. * History of cerebrovascular accident (i.e. thrombotic or hemorrhagic stroke) within 3 months prior to study entry.