Harvoni hepatitis C drug. Pills for the combination drug Harvoni, used to treat chronic hepatitis C infections. It contains the drugs sofosbuvir and ledipasvir. Sofosbuvir is an antiviral drug that works by inhibiting the enzyme that the virus uses to replicate its RNA (ribonucleic acid) genome. Ledipasvir is an antiviral protease inhibitor drug that inhibits the action of a protein that is vital for RNA replication. The hepatitis C virus infects liver cells causing an inflammatory disease that can lead to degeneration and scarring (cirrhosis). Harvoni cures 90 per cent of patients. Produced by Gilead Sciences, this drug was first approved for use in October 2014.