Antiviral Drugs Against Severe Fever With Thrombocytopenia Syndrome Virus Infection

Takayama-Ito, Mutsuyo; Saijo, Masayuki

Hexachlorophene Yuan et al. (2019) screened an FDA-approved drug library that contained 1,528 drug compounds and identified five that inhibited SFTSV replication at concentrations of <10 µM, including two antibacterial and antifungal disinfectants (hexachlorophene and triclosan), a multi-kinase inhibitor for the treatment of advanced solid organ tumors (regorafenib), a small molecule agonist of the C-mannosylation of thrombopoietin receptor (c-Mpl) for the treatment of immune thrombocytopenic purpura and aplastic anemia (eltrombopag), and an antiprotozoal agent (broxyquinoline). Of them, hexachlorophene was the most potent, with an IC 50 of 1.3 ± 0.3 µM (RNA load) and 2.6 ± 0.14 µM (plaque reduction) and the highest selectivity index (50% cytotoxic concentration [CC 50 ]/IC 50 , 18.7), which was lower than that of the other four antiviral drugs identified (Table 1) . Furthermore, the results indicated that hexachlorophene treatment interfered with SFTSV entry without affecting virus-host cell attachment to the cells and virus infectivity (Yuan et al., 2019) . It was predicted that hexachlorophene would bind to the deep hydrophobic pocket between domains I and III of the SFTSV Gc glycoprotein and would interfere with cell membrane fusion.