PREDICTIVE FACTORS OF A RESPONSE TO INTERFERON THERAPY IN CHRONIC HEPATITIS-C

To determine predictive factors of response to interferon (IFN) therap y in chronic hepatitis C patients, we administered IFN-alpha, 6 millio n U, intramuscularly daily for 2 consecutive weeks, then three times a week, to 136 patients judged to have chronic hepatitis C virus (HCV) infection according to HCV-RNA positivity. We also investigated the mo st effective length of IFN-alpha treatment according to efficacy facto rs, i.e., histological activity index, HCV-RNA genotype, and HCV-RNA l evels. Patients were classified either into a short-term group (entire treatment period 16 weeks), standard-term group (24 weeks), and long- term group (40 weeks). Patients were assessed as complete responders ( CR) if their HCV-RNA became negative and their alanine aminotransferas e (ALT) decreased to less than or equal to 39 IU/L after 18 months of treatment or nonresponders in other cases. Results showed that HCV-RNA levels and genotype were statistically significant predictive factors . CR rates in the standard- and long-term groups were significantly hi gher than in the short-term group (p < 0.05). In patients with low HAI scores, the long-term group showed the highest CR rate. In patients w ith low virus counts, the CR rate increased to 73% in the 24th week an d 100% in the 40th week. CR rates in patients with HCV-RNA genotype 1b and 2a or 2b also increased as the treatment period became longer. Fo r efficacy, a 24-week treatment period was necessary. In patients with mild liver tissue damage or low virus counts, 40 weeks of treatment p roved highly useful.