BACKGROUND: Hepatitis C virus (HCV) infection is highly prevalent and is associated with substantial morbidity and mortality among persons infected with the human immunodeficiency virus (HIV). We compared the efficacy and safety of pegylated interferon alfa-2a (peginterferon alfa-2a) plus either ribavirin or placebo with those of interferon alfa-2a plus ribavirin for the treatment of chronic HCV infection in patients who were also infected with HIV.METHODS: A total of 868 persons who were infected with both HIV and HCV and who had not previously been treated with interferon or ribavirin were randomly assigned to receive one of three regimens: peginterferon alfa-2a (180 μ g per week) plus ribavirin (800 mg per day),peginterferon alfa-2a plus placebo, or interferon alfa-2a(3 million IU three times a week) plus ribavirin. Patients were treated for 48 weeks and followed for an additional 24 weeks. The primary end point was a sustained virologic response (defined as a serum HCV RNA level below 50 IU per milliliter at the end of follow-up, at week 72). RESULTS:The overall rate of sustained virologic response was significantly higher among the recipients of peginterferon alfa-2a plus ribavirin than among those assigned to interferon alfa-2a plus ribavirin (40 percent vs. 12 percent, P<0.001), or peginterferon alfa-2a plus placebo(40 percent vs. 20 percent, P<0.001). Among patients infected with HCV genotype 1, the rates of sustained virologic response were 29 percent with peginterferon alfa-2a plus ribavirin, 14 percent with peginterferon alfa-2a plusplacebo, and 7 percent with interferon alfa-2a plus ribavirin.The corresponding rates among patients infected with HCV genotype 2 or 3 were 62 percent, 36 percent,and 20 percent. Neutropenia and thrombocytopenia were more common among patients treated with regimens that contained peginterferon alfa-2a, and anemia was more common among patients treated with regimens containing ribavirin. CONCLUSIONS: Among patients infected with both HIV and HCV, the combination of peginterferon alfa-2a plus ribavirin was significantly more effective than either interferon alfa-2a plus ribavirin or peginterferon alfa-2a monotherapy. BACKGROUND: Hepatitis C virus (HCV) infection is highly prevalent and is associated with substantial morbidity and likely others who infected with the human immunodeficiency virus (HIV). We compared the efficacy and safety of pegylated interferon alfa-2a (peginterferon alfa-2a) plus either ribavirin or placebo with those of interferon alfa-2a plus ribavirin for the treatment of chronic HCV infection in patients who were also infected with HIV. METHODS: A total of 868 persons who were infected with both HIV and HCV and who had not previously were treated with interferon or ribavirin were randomly assigned to receive one of three regimens: peginterferon alfa-2a (180 μg per week) plus ribavirin (800 mg per day), peginterferon alfa-2a plus placebo, or interferon alfa-2a Patients were treated for 48 weeks and followed for an additional 24 weeks. The primary end point was a sustained virologic response (defined as a serum HCV RNA level b elow 50 IU per milliliter at the end follow-up, at week 72). RESULTS: The overall rate of sustained virologic response was significantly higher among the recipients of peginterferon alfa-2a plus ribavirin than among those assigned to interferon alfa-2a plus ribavirin (40 percent vs. 12 percent, P <0.001), or peginterferon alfa-2a plus placebo (40 percent vs. 20 percent, P <0.001) percent with peginterferon alfa-2a plus ribavirin, 14 percent with peginterferon alfa-2a plusplacebo, and 7 percent with interferon alfa-2a plus ribavirin. The corresponding rates among patients infected with HCV genotype 2 or 3 were 62 percent, 36 percent, and 20 percent. Neutropenia and thrombocytopenia were more common among patients treated with regimens that contained peginterferon alfa-2a, and anemia was more common among patients treated with regimens containing ribavirin. CONCLUSIONS: Among patients infected wi th both HIV and HCV, the combination of peginterferon alfa-2a plus ribavirin was significantly more effective than either interferon alfa-2a plus ribavirin or peginterferon alfa-2a monotherapy.