Chikungunya virus (CHIKV) causes a febrile disease associated with chronic arthralgia, which may progress to neurological impairment. Chikungunya fever (CF) is a consolidated public health problem, in tropical and subtropical regions of the world, where control of CHIKV vector, mosquitos of the Aedes genus, failed. Since there is no vaccine or specific treatment against CHIKV, infected patients receive only palliative care to alleviate pain and arthralgia. Thus, drug repurposing is necessary to identify antivirals against CHIKV. Recently, the structure and activity of CHIKV RNA polymerase was partially resolved, revealing similar aspects with the enzyme counterparner on other positive sense RNA viruses, such as members of the Flaviviridae family. We then evaluated if sofosbuvir, clinically approved against hepatitis C virus RNA polymerase, which also aims to dengue, Zika and yellow fever viruses replication, would inhibit CHIKV replication. Indeed, sofosbuvir was 5-times more selective in inhibiting CHIKV production in human hepatoma cells than ribavirin, a pan-antiviral drug. Although CHIKV replication in human induced pluripotent stem cell (iPS)-derived astrocytes was less sensitive to sofosbuvir, compared to hepatoma cells; this drug still impaired virus production and cell death in a MOI-dependent manner. Sofosbuvir also exhibited antiviral activity in vivo, by preventing CHIKV-induced paw oedeme in adult mice, at 20 mg/kg/day, and mortality on neonate mice model, at 40 and 80 mg/kg/day. Our data demonstrates that a prototypic alphavirus, CHIKV, is also susceptible to sofosbuvir. Since this is a clinically approved drug, it could pave the way to become a therapeutic option against CF.

Beyond members of the Flaviviridae family, sofosbuvir also inhibits chikungunya virus replication