Sofibibuvir is a prodrug, which can be metabolized to 2 '- deoxy-2' - deoxy-2 '- α- Fluorine- β- C-methyluridine-5 '- monophosphate, used in the treatment of hepatitis C. Sofibvir is a direct acting antiviral drug, which inhibits HCV RNA dependent RNA polymerase, NS5B Gene. NS5B Gene is essential for HCV replication.