Used in the treatment of chronic hepatitis C virus (HCV) infection, particularly genotypes 1, 3, and 4. It functions as an NS5A replication complex inhibitor, blocking viral replication and assembly. Often combined with other antivirals like sofosbuvir to achieve high cure rates. Effective in both treatment-naïve patients and those who have failed prior therapies. Also used in patients with HIV co-infection and liver cirrhosis, offering a pan-genotypic activity with a high barrier to resistance.