Purpose / DescriptionThe IDEAL Study is one of the largest trials of both forms of peginterferon alfa, designed as a head-to-head comparison of the two forms of peginterferon alfa (2a versus 2b) and to also compare two doses of peginterferon alfa-2b. Treatment-naïve patients with genotype 1 infection were randomly assigned to one of three treatment arms: (1) standard-dose (1.5 mcg/kg) peginteferon alfa-2b plus ribavirin (800-1400 mg/day), (2) low-dose (1 mcg/kg) peginteferon alfa-2b plus ribavirin (800-1400 mg/day), and (3) standard-dose (180 mcg) peginteferon alfa-2a plus ribavirin (1000-1200 mg/day). Patients who had an early virologic response had markedly higher SVR rates than those who do not achieve an early virologic response. The rates of sustained virologic responses and the incidence of adverse effects did not differ substantially across these regimens.