Consensus interferon: a novel interferon for the treatment of hepatitis C

Although alpha interferons are currently the only therapies approved for treatment of HCV infection approximately half of the treated patients do not respond to the standard regimen of IFN-alpha-2b 3 MU administered 3 times per week (tiw) for 6 to 12 months. Of those who do demonstrate a response, 50-80% will relapse within 6 months after treatment cessation. Thus, the overall response to treatment is low. This paper focuses on studies that have been conducted with a newly developed interferon, Consensus Interferon (CIFN), in the treatment of chronic Hepatitis C. This type-1 interferon links the most common occurring amino acid sequences at each position of available natural alpha interferons into one 'consensus' protein. The thus synthesized molecule shows a 10-fold higher in vitro biological activity as compared to single recombinant IFN-alpha-2b or IFN-alpha-2a, possibly due to its greater binding affinity to interferon receptors. In patients with chronic hepatitis C, CIFN 9 micrograms, three times weekly for 24 weeks, proved to be equally efficacious and as safe as IFN-alpha-2b, but compared to 3 MU IFN-alpha-2b, CIFN 9 micrograms demonstrated improved responses in patients with high baseline viral titres. Retreatment of subjects who had responded but relapsed following standard dose IFN therapy for 6 months, with 15 micrograms CIFN three times weekly for 48 weeks, resulted in a sustained virological response rate of 58%. When previous non-responders to standard IFN therapy were retreated a 13% sustained response to the higher dose of CIFN for 48 weeks was observed. The higher dose of CIFN was well-tolerated and not associated with an increase in the incidence of side-effects. CIFN proved to be an effective and safe therapy in the treatment of patients with chronic hepatitis C and the retreatment of patients who either failed previous interferon treatment or had relapsed after its cessation.