Ledifos Tablets Ledifos is a fixed-dose combination of Ledipasvir (an HCV NS5A inhibitor) and Sofosbuvir (a nucleotide analogue NS5B polymerase inhibitor) used for the treatment of chronic Hepatitis C Virus (HCV) infection. Ledipasvir inhibits the HCV NS5A protein, which is essential for viral RNA replication and virion assembly. Sofosbuvir is a nucleotide prodrug that undergoes intracellular metabolism to form the active triphosphate GS-461203, which incorporates into HCV RNA via the NS5B polymerase and acts as an obligate chain terminator. Indicated for the treatment of chronic hepatitis C genotype 1, 4, 5, or 6 infection in adult and pediatric patients.