The purpose of the study was to determine safety and efficacy of 48 weeks treatment with Thymosin alpha 1 (Talpha1) in combination with pegylated interferon (PEGIFN) alpha2a and ribavirin (RBV) in adult patients with chronic hepatitis C (CHC) already treated with, and not responding to previous courses of PEGIFN alpha plus RBV combination therapy, in comparison with a concurrent group treated with PEG IFN alpha2a in combination with RBV and placebo.