Camostat, also known as FOY 305, is a serine protease inhibitor. Camostat is used in the treatment of some forms of cancer and is also effective against some viral infections, as well as inhibiting fibrosis in liver or kidney disease or pancreatitis. It is an inhibitor of the enzyme transmembrane protease, serine 2 (TMPRSS2). Inhibition of TMPRSS2 partially blocked infection by SARS-CoV and Human coronavirus NL63 in HeLa cell cultures. In vitro study showed that camostat significantly reduces the infection of Calu-3 lung cells by SARS-CoV-2, the virus responsible for COVID-19.