This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is a Phase II, open-label, two-arm, long-term maintenance therapy study. This trial is designed to study whether long-term maintenance with pegylated-interferon alfa-2a (PEG-IFN) reduces the rate of liver fibrosis progression in subjects with HCV/HIV co-infection who have failed to achieve or maintain HCV loads below the limit of detection during treatment with PEG-IFN plus ribavirin. Both HCV treatment na¿ve and previously treated subjects will be enrolled.