What are the main drugs under investigation that block SARS-CoV-2 cell entry?
There are drugs that interfere with ACE2 and TMPRSS2, which are molecules used by the virus to enter the cell.9,181For example, camostat mesylate is a clinically proven serine protease inhibitor with affinity for TMPRSS2. It has shown activity against SARS-CoV-2 in human lung Calu-3 cells.9 Several drugs that target virus internalization are being investigated, including chloroquine phosphate and hydroxychloroquine, which have shown limited efficacy in humans and raised concerns due to side effects (see questions below ).163,182 A combination of cepharanthine (an anti-inflammatory alkaloid), selamectin (an avermectin used as an anti-helminthic and parasiticide drug in veterinary medicine) and mefloquine hydrochloride (used for the prophylaxis and treatment of malaria),183 and meplazumab184(see questions below ), among others. Although still at the experimental level, a clinical-grade human recombinant ACE2 has shown efficacy to block SARS-CoV-2 growth in kidney epithelial cells (Vero cells) (Figure. 1 ).185