The study, published in the journal Cells, found that the approved protease inhibitor aprotinin displayed activity against SARS-CoV-2, the coronavirus that causes Covid-19, in concentrations that are achieved in patients.
According to the researchers, aprotinin aerosols are approved in Russia for the treatment of influenza and could be readily tested for the treatment of Covid-19.
Aprotinin inhibits the entry of SARS-CoV-2 into host cells and may compensate for the loss of host cell protease inhibitors that are downregulated upon SARS-CoV-2 infection.
"The aprotinin aerosol has been reported to be tolerated extremely well in influenza patients. Hence, it may have a particular potential to prevent severe Covid-19 disease when applied early after diagnosis," said study author Martin Michaelis from the University of Kent in the UK.
"Aprotinin has previously been shown to inhibit TMPRSS2 gene and has been suggested as a treatment option for influenza viruses and coronaviruses. Herein, we investigated the effects of aprotinin against SARS-CoV-2," Michaelis added.
The findings showed that aprotinin displayed anti-SARS-CoV-2 activity in different cell types (Caco2, Calu-3, and primary bronchial epithelial cell air-liquid interface cultures) and against four virus isolates.
"An approved aprotinin aerosol may have the potential for the early local control of SARS-CoV-2 replication and the prevention of Covid-19 progression to a severe, systemic disease," the study authors noted.