for people ages 18 years and up (full criteria)
study started
estimated completion



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

Official Title

COVID-19 Post-hospital Thrombosis Prevention Trial: An Adaptive, Multicenter, Prospective, 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


Covid19, COVID-19, Thrombosis, Apixaban, Apixaban 2.5 MG


You can join if…

Open to people ages 18 years and up

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

You CAN'T join if...

  • 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)
  • Pregnancy
  • 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


  • UCSF at Zuckerberg San Francisco General Hospital
    San Francisco California 94110 United States
  • Torrance Medical Center
    Torrance California 90502 United States
  • New Ananda Medical and Urgent Care, Inc.
    S. El Monte California 91733 United States
  • Mazur and Statner MD PC
    Thousand Oaks California 91360 United States
  • Stanford University School of Medicine
    Palo Alto California 94304 United States


in progress, not accepting new patients
Start Date
Completion Date
Thomas L. Ortel
Phase 3 COVID-19 Research Study
Study Type
At least 1219 people participating
Last Updated