In this retrospective analysis, we demonstrated that baseline and on-treatment factors, including lower serum HCV RNA concentration, higher ALT quotient, absence of cirrhosis, younger age, white non-Latino ethnicity and daily on-treatment ribavirin dose >13 mg/kg, were independently associated with achieving RVR and cEVR in patients infected with HCV genotype 1 and treated with peginterferon alfa-2a plus ribavirin for 48 weeks. The gene discussed is GPT; the disease is Cirrhosis.