Can treatment for a rare blood disorder offset extreme immune responses to COVID-19?

Red blood cells and white blood cells travel inside of a blood vessel.

Millions of people throughout the world have been infected by SARS-CoV-2, the pathogen that causes COVID-19. Hundreds of thousands of people have died throughout the pandemic. In addition to rapidly developing and testing vaccines to reduce the risk of SARS-CoV-2 transmission, research teams are testing new therapies to help infected individuals recover from infections.

A new trial led by the National Heart, Lung, and Blood Institute (NHLBI) will explore how the oral medication fostamatinib strengthens immune function for people with a hyperextended immune response to COVID-19. The trial will enroll 60 patients at the National Institutes of Health Clinical Center in Bethesda, Maryland, and at Inova Health System, starting with Inova Fairfax Hospital in Falls Church, Virginia.

The strength of fostamatinib is its ability to take a “deep dive” into biological pathways and immune signaling without overpowering immune function. The researchers will study how this targeted therapy supports and regulates the function of white blood cells in response to injury and infection. This includes analyzing neutrophil infiltration and macrophage responses. The research team will also study the drug’s ability to offset hyperextended immune responses, such as immunothrombosis or a cytokine storm, that some patients develop 6-14 days into COVID-19. This can result in blood clots or the body’s immune system attacking itself.

Half of the hospitalized COVID-19 patients enrolled in the randomized, double-blind clinical trial will serve as controls.

Fostamatinib, sold as Tavalisse from Rigel Pharmaceuticals, Inc., is used to treat immune thrombocytopenic purpia (ITP), a rare autoimmune or blood disorder.

Rear Admiral Richard Childs, M.D., clinical director of the NHLBI, notes the best-case scenario for the study is that the treatment could help at-risk individuals, such as people with compromised immune function, the elderly, or those who may not respond to a future COVID-19 vaccine, recover faster if they have an extreme immune response to the novel coronavirus. This could mean avoiding assisted breathing support in the intensive care unit.