Approximately 200 million people worldwide are infected with the hepatitis C virus (HCV). The vast majority develop chronic infection that is associated with severe liver disease, including hepatic fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Thus, there is a need for the development of treatments that cure infected individuals. Compounds that bind to the non-structural protein 5A (NS5A) have shown antiviral activity in advances clinical trials. In collaboration with Tibotech, we study the mechanism of action of selected molecules with the ultimate goal to provide tools to improve this class drugs.