Anti-interferon-α neutralizing antibody induced telaprevir resistance under the interferon-α plus telaprevir treatment in vitro.

Although the development of anti-interferon (IFN)-α neutralizing antibodies (NAbs) is likely to be a common clinical problem for patients with various diseases treated with IFN, anti-IFN-α NAb has been exceptionally considered to have no clinical significance in the treatment of chronic hepatitis C with pegylated IFN-α (Peg-IFN-α). However, we recently clarified that the presence of NAb was associated with a non-response to the Peg-IFN plus ribavirin (RBV) therapy. In this study, we used the HCV-replicon system with genotype 1b, and investigated the role of anti-IFN-α NAb in the response to telaprevir (TVR)-containing new antiviral therapy for hepatitis C virus (HCV). Anti-IFN-α NAb-positive sera specifically inhibited the anti-HCV effects of IFN-α, without any effect on the activity of IFN-ß in vitro. The NAb-positive sera also inhibited the IFN-α-dependent induction of interferon-stimulated genes, MxA and OAS-1, in a dose-dependent manner. Although TVR monotherapy decreased the HCV-RNA in vitro, the HCV-RNA was increased again with the development of TVR-resistant mutations. When IFN-α was administrated with TVR, the replication of HCV was continuously suppressed for more than a month. However, in the presence of anti-IFN-α NAb-positive sera, even when IFN-α was combined with TVR, the levels of HCV-RNA exhibited a time-course similar to that with TVR monotherapy, and HCV with TVR-resistant mutations emerged. In conclusion, our findings suggest that the presence of IFN-α NAb decreases the antiviral effects of IFN-α and may be related to the development of TVR-resistant mutated viruses.

Hepatitis C virus relapse was suppressed by long-term self-injection of low-dose interferon in patients with chronic hepatitis C after pegylated interferon plus ribavirin treatment.

AIM: The recommended treatment for chronic hepatitis C is a combination of pegylated interferon (PEG IFN) plus ribavirin (RBV). However, the sustained virological response (SVR) rate of PEG IFN-RBV therapy was approximately 50% in patients with genotype 1b and a high viral load. Thus, we compared the efficiencies and side-effects of PEG IFN-RBV and self-injected low-dose natural (n) IFN-α in patients with hepatitis C virus (HCV). METHODS: A prospective, multicenter, open-label study was conducted in 12 Japanese institutions. A total of 129 patients with chronic hepatitis C and no detectable HCV after 24-72 weeks of PEG IFN-RBV treatment were assigned to the control (n = 82) or treated (n = 47) group. Treated patients received 3 million units of nIFN-α 2-3 times/week over 96 weeks. The groups were compared regarding treatment efficiency and side-effects. RESULTS: Significant treatment success regarding virus negativation rates was found, with 89% and 73% for the treated and control groups, respectively (P = 0.039). In contrast, there was no difference in relapse rate between the groups 24 weeks after the 96-week nIFN-α treatment (P = 0.349). However, when early viral responders and late viral responders (LVR) were separated, LVR patients responded significantly to the treatment with 90% sustained virological response, compared to 53% for the control group (P = 0.044). The side-effects of nIFN-α were less than that of PEG IFN-RBV treatment. CONCLUSION: Self-injected nIFN-α has larger benefits than prolonged PEG IFN-RBV for chronic hepatitis C patients with high viral loads of genotype 1b who fail to achieve early viral response during initial combination treatment.