Velpatasvir is innovated by Gilead to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients. Velpatasvir is a Direct-Acting Antiviral (DAA) medication used together with Sofosbuvir. The mechanism of action is as a Breast Cancer Resistance Protein Inhibitor, and P-Glycoprotein Inhibitor, and Organic Anion Transporting Polypeptide 1B1 Inhibitor, and Organic Anion Transporting Polypeptide 1B3 Inhibitor, and Organic Anion Transporting Polypeptide 2B1 Inhibitor. It blocks NS5A, a protein necessary for hepatitis C virus replication assembly.