NIH starting enrollment for third trial of blood clotting treatments for COVID-19

The National Institutes of Health has launched the last of three Phase 3 clinical trials to evaluate the safety and effectiveness of blood thinners to prevent life-threatening blood clots in adults diagnosed with COVID-19. The first patient in the trial was enrolled on February 15.  

MEDIA RELEASE: March 8, 2021

Part of the Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) initiative, the trial explores the use of Eliquis® (apixaban 2.5 mg), a blood thinner, or anticoagulant, donated by Bristol Myers Squibb/Pfizer, in patients who have been discharged from the hospital following a diagnosis of moderate-to-severe COVID-19, the disease caused by SARS-CoV-2.    

The ACTIV-4 Convalescent trial is the third of the ACTIV-4 Antithrombotics master protocol for adaptive trials. The other two – one focused on hospitalized COVID-19 patients and the other on patients with COVID-19 who have not been hospitalized – are already underway. The trials are being conducted at more than 100 sites around the world. These trials are overseen by the National Heart, Lung, and Blood Institute (NHLBI), part of the NIH.

Early in the coronavirus pandemic, researchers noticed that many patients who died from COVID-19 had formed blood clots throughout their bodies, including in their smallest blood vessels. This unusual clotting, one of many life-threatening effects of the disease, has caused multiple health complications, from organ damage to heart attack, stroke, and pulmonary embolism.   

 The ACTIV-4 trials will answer critical questions about the proper use of blood thinners or anticoagulants – called antithrombotics – in the treatment of patients with COVID-19, particularly those who suffer from life-threatening blood clots.      

 Recruiting at sites with a significant COVID-19 burden, ACTIV-4 Convalescent is a randomized and placebo-controlled trial.  Researchers will assess if, within 45 days of being hospitalized, patients develop any thrombotic complication – heart attack, stroke, blood clots in major veins and arteries, deep vein and pulmonary thrombosis, or death.      

Trial planning and development work is being done through a collaborative effort with a number of institutions, including Duke University, Durham, North Carolina, University of Pittsburgh; University of Illinois at Chicago; Brigham and Women’s Hospital, Boston; the Medical College of Wisconsin; the University of California, San Francisco; and the University of Ottawa and the Ottawa Hospital Research Institute.

COVID-19 Thrombosis Prevention Trials: Post-hospital Thromboprophylaxis   

About the National Heart, Lung, and Blood Institute (NHLBI): NHLBI is the global leader in conducting and supporting research in heart, lung, and blood diseases and sleep disorders that advances scientific knowledge, improves public health, and saves lives. For more information, visit   

About the National Institutes of Health (NIH): NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

NIH…Turning Discovery Into Health®


Posted in AZBio News, COVID-19 News and Info.