Breakthrough in Chronic Hepatitis C During Recombinant Alpha Interferon Therapy

One hundred forty-one patients with chronic hepatitis C were treated with recombinant interferon alpha 2a (r-IFNα2a) (3MU three times/week for 12 months). Alanine aminotransferase levels returned to normal in 85 of them during treatment. Eleven out of 85 (12.9%) had cytolytic relapses) (breathrough) between the 2nd and 7th month of IFN therapy (median, 4 months), indicating loss of clinical efficacy of r-IFNα2a. Most of these patients (6/9) developed neutralizing antibodies to r-IFNα2a before the breakthrough occurred. Continuing the treatment or increasing the r-IFN dose did not have any effect. Switching to natural lymphoblastoid IFN (l-IFNαN1) rapidly restored a complete response, independent of the dose (3 or 6 MU, three times/week). In conclusion, careful biochemical monitoring is recommended in the first period of r-IFNα2a treatment, and if breakthrough occurs, the switch to l-IFNαN1 is indicated to restore the clinical response.