Nafamostat mesylate (brand name: Fusan), which is the drug used to treat acute pancreatitis, may effectively block the requisite viral entry process the new coronavirus (SARS-CoV-2) uses to spread and cause disease (COVID-19). The University of Tokyo announced these new findings on March 18, 2020. According to the new research, Nafamostat can prevent the fusion of the envelope of the virus with host cell surface membranes, the first step in infection with the causative virus SARS-CoV-2. Nafamostat can inhibit the membrane fusion at a concentration less than one-tenth that of Camostat mesylate (brand name: Foypan)