Rapid progression of liver disease to liver failure has been observed in people coinfected with HIV and HCV. This observation appears to be directly related to an increase in the rate of fibrotic progression in the liver compared to people infected with HCV alone. PEG-IFN and ribavirin are used in standard treatment of HCV. This study tested the effectiveness of using PEG-IFN in reducing the rate of liver fibrosis progression in participants coinfected with HIV and HCV who could not lower their HCV viral load to undetectable or who could not maintain their HCV viral load at undetectable on PEG-IFN and ribavirin treatment.