samatasvir + simeprevir + TMC647055 + ritonavir + ribavirin

This is a **combination regimen** comprising five distinct antiviral agents for the treatment of **chronic hepatitis C virus (HCV) infection**. The combination includes: - **Samatasvir** (IDX719), an NS5A inhibitor; - **Simeprevir**, an NS3/4A protease inhibitor; - **TMC647055**, a non-nucleoside NS5B polymerase inhibitor; - **Ritonavir**, used as a pharmacokinetic enhancer to boost the levels of TMC647055 via CYP3A inhibition; - **Ribavirin**, a guanosine analogue antiviral that augments SVR rates, especially in difficult-to-treat HCV populations. This multidrug combination is designed to address different targets within the HCV replication cycle, improving efficacy across viral genotypes and in patients with previous treatment failure. It is administered orally, typically once daily for 12 weeks, and has been tested in clinical trials involving genotype 1 (including subtypes 1a and 1b) HCV-infected patients, both treatment-naive and those who have relapsed after interferon/ribavirin therapy[1][3][5][9]. The regimen represents a direct-acting antiviral (DAA) approach, aiming for higher sustained virologic response (SVR) rates and improved tolerability relative to older interferon-based treatments[1][2].