Short term and two-step interferon therapy for chronic hepatitis C patients with low HCV RNA levels.

Objective: Chronic hepatitis C patients with low HCV RNA levels were treated with short term therapy and for patients in whom the virus was not eliminated in this short therapy, we designed a two-step IFN therapy. Subjects: There were 31 patients with chronic hepatitis C whose HCV RNA level before IFN therapy was <1.0 Meq/ml or 100 kcopies/ml. The HCV serotypes were serotype 1 in nine patients, serotype 2 in 21 and mixed type in one. A 9--10 MU per day of natural IFN was administered daily for 2 weeks, then three times weekly for 8 weeks (the first therapy), then the therapy was ended. For patients in whom the virus was not eliminated, an additional IFN therapy was administered during the decreasing phase of HCV RNA (second therapy). The historical control group consisted of 57 patients who fulfilled the above criteria and underwent IFN therapy for 24 weeks. Complete responders were defined as patients in whom HCV RNA was not detected in their serum for at least 6 months after the end of treatment. Results: Nineteen (61%) of 31 patients who completed the first therapy showed complete response to the first therapy. Eight patients underwent the second therapy and the complete response rates were 0/4 and 2/4 (50%) in the serotype 1 and 2 groups, respectively. The overall complete response rate was 44% (4/9) in the serotype 1 group, 76% (16/21) in the serotype 2 group and 100% (1/1) in the mixed type. The complete response rate in the historical control group was 70% (40/57), showing no difference in efficacy. However, the IFN dosage was significantly lower in the patients than in the control group (P<0.001). Conclusions: In patients with low HCV RNA levels and serotype 2, short term therapy is sufficiently effective. Furthermore, 50% of the complete response was obtained by an additional second therapy. This therapy design showed high efficacy and was cost-effective in these patients.