Asunaprevir is primarily used in the treatment of chronic hepatitis C virus (HCV) infection. It is often administered in combination with other antiviral medications, such as daclatasvir, to enhance its efficacy. The drug works by inhibiting the NS3/4A protease, an enzyme essential for viral replication, thereby reducing the viral load in patients. This combination therapy is particularly effective for patients with HCV genotype 1b, offering a high rate of sustained virologic response (SVR). Asunaprevir is also considered a valuable option for patients who have previously failed other treatments or those who cannot tolerate interferon-based therapies. Its use has significantly improved outcomes for individuals with chronic HCV, contributing to better liver health and reducing the risk of complications such as cirrhosis and hepatocellular carcinoma.