COVID-19 Thrombosis Prevention Trials: Post-hospital Thromboprophylaxis

  • days left to enroll
  • participants needed
  • sponsor
    Thomas L. Ortel
Updated on 14 June 2022


A multicenter, adaptive, randomized platform trial evaluating the efficacy and safety of antithrombotic strategies in patients with COVID-19 following hospital discharge


This study is an adaptive, prospective, randomized platform trial designed to compare the effectiveness and safety of antithrombotic therapy with no antithrombotic therapy after hospitalization for 48 hours or longer for COVID-19. For Stage 1 of this study, participants will be randomized to either prophylactic anticoagulation or matching placebo for 30 days, and then followed for an additional 60 days after the completion of treatment (total duration of follow-up, 90 days).

The primary objective is to determine the most effective and safe antithrombotic strategy to prevent the composite outcome of symptomatic deep vein thrombosis, pulmonary embolism, other venous thromboembolism, ischemic stroke, myocardial infarction, other arterial thromboembolism, and all-cause mortality by 30 days following discharge from the hospital.

Biobanking of samples for future biomarker and mechanistic studies will be available for centers able to participate and collect samples from eligible participants. Samples will be collected at the time of enrollment and after the completion of 30 days of therapy

Condition Covid19
Treatment Placebo, Apixaban 2.5 mg
Clinical Study IdentifierNCT04650087
SponsorThomas L. Ortel
Last Modified on14 June 2022


Yes No Not Sure

Inclusion Criteria

• Age ≥ 18 years
PCR-positive COVID-19 infection
Hospitalized for two or more days

Exclusion Criteria

Pre-existing indication for anticoagulation (e.g., pulmonary embolism or deep vein thrombosis; atrial fibrillation; mechanical cardiac valve)
Contraindication to antithrombotic therapy (e.g., known bleeding within the last 30 days requiring emergency room presentation or hospitalization; major surgery within 14 days; ischemic stroke, intracranial bleed or neurosurgery within 3 months
Platelet count < 50,000/mcL
Hemoglobin <8 gm/dL
Renal insufficiency (eGFR < 30 mL/min/1.73 m2)
Prison inmate
Life expectancy less than 90 days
Unwilling or unable to provide informed consent/unwilling or unable to complete the study protocol
Dual antiplatelet therapy that cannot be discontinued
Concomitant need for strong inducers/inhibitors of p-gp or CYP3A4
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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