Defibrotide for the Treatment of Severe COVID-19

Inclusion Criteria: 1. Age ≥18 years. 2. Active COVID-19 infection confirmed by positive SARS-CoV-2 PCR. 3. Radiographic evidence of bilateral pulmonary infiltrates. 4. A life expectancy of at least 24 hours. 5. Score of 4-7 on the WHO ordinal scale. 6. Prophylactic dose anticoagulation is allowed for enrollment into cohort 1. Therapeutic dose anticoagulation for active thrombosis, ECMO, and/or continuous renal replacement therapy (CRRT) is allowed for enrollment into cohort 2 if there is no evidence of bleeding after at least 24 hours of anticoagulation. 7. Patient or surrogate able to provide informed consent Exclusion Criteria: 1. Clinically significant acute bleeding. 2. Concomitant use of thrombolytic therapy (e.g. t-PA). 3. Hemodynamic instability, defined as a requirement for \>1 vasopressor agent for enrollment into cohort 1, and a requirement for \>2 vasopressor agents for enrollment into cohort 2 4. Known allergy or hypersensitivity to DF. 5. Pregnant or lactating.