Sequential randomized, multicenter, active comparator study to evaluate the hypothesis that rNAPc2 (AB201), a novel, potent and highly selective tissue factor inhibitor with anticoagulant, anti-inflammatory and potential antiviral properties, shortens time to recovery compared to heparin in hospitalized patients with COVID-19 and elevated D-dimer levels.

Sequential randomized, multicenter, active comparator study to evaluate the hypothesis that rNAPc2, a novel, potent and highly selective tissue factor inhibitor with anticoagulant, anti-inflammatory and potential antiviral properties, shortens time to recovery compared to heparin in hospitalized patients with COVID-19 and elevated D-dimer levels. Study participants and Clinical Endpoint Committee (CEC) members assessing the clinical endpoints will be blinded to treatment assignment. The protocol comprises sequential Phase 2b and Phase 3 studies. Analysis of Phase 2b data could lead to study discontinuation, adjustment of eligibility criteria or sample size, and will inform the rNAPc2 dose level to be studied in Phase 3.

Inclusion Criteria:

1. Age ≥ 18 years and ≤ 90 years at the Screening assessment
2. Weight ≥ 50 kg at randomization
3. Hospitalized with a diagnosis of COVID-19 and in need of inpatient medical care
4. Positive for SARS-CoV-2 on nasopharyngeal, oropharyngeal or other tissue/body fluid samples by PCR or validated other test of ongoing infection (not an antibody test for prior exposure), within seven (7) days of hospitalization or screening assessment
5. D-dimer level > upper limit of normal at screening
6. Provided electronic or written informed consent, either personally or through a legally authorized representative (LAR)
7. Must agree not to participate in a concurrent interventional study involving anticoagulation or anti-platelet therapy
8. Female patients of reproductive or child-bearing potential must be willing to use an effective method of contraception for the duration of the study, and male patients must be willing to use an effective method of contraception to avoid partner pregnancy and abstain from sperm donation for at least 90 days after last dose

Exclusion Criteria:

1. High bleeding risk, e.g. major surgery within prior 1 month, history of a major bleed while receiving anticoagulation, recent hemorrhagic stroke, current or planned (during current hospitalization) dual anti-platelet therapy, platelet count <25,000/uL, current therapeutic anticoagulation for a medical indication other than COVID-19, e.g. atrial fibrillation, known thrombosis, hereditary or acquired coagulopathy treated with therapeutic anticoagulation. Patients receiving prophylactic anticoagulation are eligible if they are willing to discontinue current anticoagulation.
2. Sustained systolic blood pressure < 90 mmHg considered to be clinically significant
3. Persistent eGFR <20 ml/min/1.73m2
4. Known severe liver disease (e.g. bilirubin >3.5 mg/dL (60 umol/L))
5. Life expectancy estimated to be < 72 hours based on current clinical condition
6. Anticipated hospital discharge or transfer within 5 days based on current clinical condition
7. Known anti-phospholipid syndrome
8. Unable to receive heparin, e.g. history of heparin-induced thrombocytopenia and thrombosis (HITT)
9. Participation in any interventional clinical study with an investigational product within seven (7) days of the Screening assessment or within 5 half-lives of the investigational agent, whichever is longer

Participant, clinical events committee members will be blind to treatment assignment. Investigator assessing outcomes will be blinded wherever possible.