LAUSR

ABSTRACT Zika virus (ZIKV), a member of the Flaviviridae family, has recently been linked to abnormal pregnancies, fetal death, microcephaly, and Guillain‐Barré syndrome in humans. Merimepodib (MMPD, VX‐497), a potent inhibitor of inosine‐5′‐monophosphate dehydrogenase (IMPDH), has shown antiviral activity against HCV and a variety of DNA and RNA viruses in vitro. In this report, we expand the antiviral spectrum of MMPD, and demonstrate that MMPD inhibits ZIKV RNA replication with an EC50 of 0.6 &mgr;M. Furthermore, MMPD reduces the virus production of ZIKV as well as several other important emerging viral pathogens such as Ebola, Lassa, Chikungunya, and Junin viruses. The inhibition can be reversed by addition of exogenous guanosine to culture media, consistent with the mechanism of action of MMPD as an IMPDH inhibitor. We also provide evidence that MMPD can be used in combination with other antivirals such as ribavirin and T‐705 (favipiravir) to enhance suppression of virus production. HighlightsMerimepodib is a potent inhibitor of IMPDH with broad spectrum antiviral activities in vitro.It inhibits Zika virus (ZIKV) RNA replication with an EC50 of 0.6 &mgr;M.It reduces the virus production of ZIKV as well as emerging viruses such as Ebola, Lassa, Chikungunya, and Junin viruses.Inhibition can be reversed by addition of exogenous guanosine.Combination with other antivirals such as ribavirin and T‐705 enhances suppression of virus production.