A small study in Greece found that the clinically approved anti-inflammatory drug anakinra, used to treat rheumatoid arthritis, improved respiratory function in patients with severe coronavirus disease 2019 (COVID-19). The eight patients also had a condition called secondary hemophagocytic lymphohistiocytosis (sHLH), which is characterized by overactivation of the immune system and organ failure.

 One patient, who did not require mechanical ventilation, improved rapidly after starting treatment with the drug and was discharged from the hospital 9 days later. But the therapy did not prevent three out of seven patients on ventilators from dying, and it's not yet clear whether it improves mortality rates. The report appears May 14 in the journal Cell Host & Microbe.

"These data argue that the administration of anakinra may be a viable treatment in severe COVID-19 with sHLH, supporting larger clinical studies to validate this concept," says senior author Evangelos J. Giamarellos-Bourboulis, a professor of internal medicine at the Medical School of the National and Kapodistrian University of Athens.

The death rate in patients with severe COVID-19 admitted to intensive care units (ICUs) is estimated to be between 50% and 65%. Severe complications of COVID-19 are thought to be driven by inflammatory responses, particularly through signaling molecules called interleukin 1β (IL-1β) and interleukin 6 (IL-6). The overproduction of IL-1β by immune cells called macrophages can cause sHLH, also known as macrophage activation syndrome, which is characterized by low counts of blood cells, excessive blood clotting, kidney injury, and liver dysfunction. Anakinra inhibits IL-1β signaling and has been shown to reduce the mortality of patients with signs of sHLH by 30%.