Camostat is a serine protease inhaler used, in the form of camostat mesilate, for the treatment of various pathologies such as certain cancers or fibrosis in kidney diseases.

CoV-2-CoRNA exploits the cell entry receptor protein, angiotensin II converting enzyme (ACE-2), to access and infect human cells. The interaction between ACE-2 and the lead protein is not in the active site. This process requires the serine protease TMPRSS2. Camostat mesilate is a potent inhibitor of serine protease. Through research on the SARS-CoV-2 coronavirus and its closely related cell entry mechanism, it has been shown that the cellular entry of SARS-CoV-2 can be blocked by camostat mesilate. In mice, camostat mesilate administered at concentrations similar to the clinically achievable concentration in humans reduced mortality from SARS-CoV-2 infection from 100% to 30-35%. In addition, another study showed that camostat mesilate reduced SARS-CoV-2 infection of Calu-3 cells.