According to the IISC researchers, Montelukast, an asthma and anti-allergen drug can inhibit viral replication in human cells by blocking the protein metabolism of coronavirus. The US FDA-approved drug has been available in the market for 20 years and is administered to treat asthma, hay fever, and hives. 

In the study published in eLife, the researchers demonstrated the binding of the C-terminal of the viral protein Nsp1 to the drug, thus, reducing the immune response and damage elicited by the virus. Dr. Tanweer Hussain, an Assistant professor, stated that the mutation rate in this protein is very low in comparison to the rest of the viral proteins. Since Nsp1 is likely to remain unchanged for any new variant, the drug targeting this protein region will be useful in controlling all the viable variants.

Hussain and his team screened 1,600 FDA-approved drugs using computational modelling to find a single drug that can bind to the Nsp1 protein site. Based on the search, montelukast, and Saquinavir, an anti-HIV drug was shortlisted. The team then performed in vitro studies on human cell culture and found Montelukast to be more effective in inhibiting protein metabolism. (Source: https://health.economictimes.indiatimes.com/news/pharma/iisc-researchers-find-asthma-drug-montelukast-can-block-crucial-sars-cov-2-protein/91086625 )