Objectives: 1. Primary objective: To Evaluate the rate of sustained virological response (SVR) of pegylated interferon alfa-2b (Peg-IFN) plus ribavirin (RBV) plus nitazoxanide (NTZ) in patients coinfected by HIV and HCV genotype 4 (HCV-4), never treated before (naïve) and with a treatment failure to a standard therapy with Peg-IFN plus RBV (experienced), and to compare it with the rate of SVR of these patients with Peg-IFN plus RBV is a historical cohort. 2. Secondary objectives: In naive, as well as in experienced patients: a) To evaluate the virological activity at weeks 4 and 12 after starting the combination of Peg-IFN plus RBV plus NTZ in HIV/HCV-4-coinfected patients. b) To analyze the safety of Peg-IFN plus RBV plus NTZ in HIV/HCV-4-coinfected patients.