sofosbuvir

Ledipasvir and sofosbuvir are both direct-acting antiviral agents. Sofosbuvir is a liver-targeted nucleotide prodrug of the active triphosphate GS-461203, which has been approved for use in HCV genotypes 1–4. It works as an inhibitor of the HCV NS5B RNA-dependent RNA polymerase, which acts as a chain terminator.