Studies of therapy with thymosin alpha1 in combination with pegylated interferon alpha2a and ribavirin in nonresponder patients with chronic hepatitis C.

Despite the use of combination therapy with pegylated interferon alpha2a (peg-IFN-alpha2a) + Ribavirin, a large proportion of patients with chronic hepatitis C (CHC) remain unresponsive to treatment. Thymosin alpha 1 (Talpha1) is an immunomodulator, which displays immunological and antiviral activities against hepatitis C virus (HCV) in preclinical clinical settings. The purpose of this study was to evaluate the efficacy and safety of a triple combination therapy with peg-IFN-alpha2a + Ribavirin + Talpha1 in CHC patients who were nonresponders to a previous course with peg-IFN-alpha2a + Ribavarin. The primary endpoint is the rate of sustained virological response (SVR). We designed a phase 3, randomized, double-blind, multicenter, prospective, placebo controlled study. Patients meeting selection criteria were randomized centrally (through IVR system) to receive either peg-IFN-alpha2a 180 mcg s.c. once weekly + Ribavirin 1000-1200 mg p.o. daily + Talpha1 1.6 mg s.c. twice weekly for 24 weeks. Patients who remained HCV-RNA positive after 24 weeks stopped treatment and were considered nonresponders. HCV-RNA negative patients continued treatment up to week 48. All patients were followed up for 24 additional weeks after the end of treatment for the evaluation of the SVR. From December 2004 to November 2006, 638 patients were screened in 52 European sites. Preliminary blinded safety analysis suggests that both regimens are well tolerated. Efficacy evaluation will be available after the opening of this blinded phase 3 trial, planned for May 2008.