The following study suggests it may be beneficial to continue IFN therapy if HCV RNA is not undetectable after initial HCV treatment.

GASTROENTEROLOGY 1999;117:1164-1172 

A Randomized, Controlled Trial of Maintenance Interferon Therapy for Patients With Chronic Hepatitis C Virus and Persistent Viremia
     MITCHELL L. SHIFFMAN,* CHARLOTTE M. HOFMANN,* MELISSA J. CONTOS, VELIMIR A. LUKETIC,* ARUN J. SANYAL,* RICHARD K. STERLING,* ANDREA FERREIRA-GONZALEZ, A. SCOTT MILLS, and CARLTON GARRET *Hepatology Section and Department of Pathology, Medical College of Virginia Commonwealth University, Richmond, Virginia

Background & Aims:: At least half of patients with chronic hepatitis C virus (HCV) fail to respond to interferon or interferon/ribavirin therapy. Histological improvement is observed in some nonresponders. We conducted a randomized, controlled trial to determine if maintenance interferon therapy could prevent histological progression in this subset of nonresponders. 

Methods: Fifty-three patients with chronic HCV were enrolled. All were HCV-RNA positive after 6 months of treatment with interferon alfa-2b but had a histological response. Twenty-seven of the patients were randomly assigned to continue interferon (3 MU 3 times weekly) for 24 months; 26 patients discontinued treatment and were observed prospectively. Alanine aminotransferase (ALT) level and HCV-RNA titer were monitored, and liver biopsy was repeated every 12 months. 

Results: Before interferon therapy, the 2 groups were well matched for all demographic factors, serum ALT (94.0 ± 15.6), log HCV-RNA titer (5.85 ± 0.15 copies/mL), histology score (9.5 ± 0.2), and percentage with cirrhosis (25%). After 6 months of treatment, significant reductions (P < 0.05) in serum ALT level (62.6 ± 9.6), log HCV-RNA titer (4.79 ± 0.13 copies/mL), and hepatic inflammation (4.0 ± 0.2) were observed. These improvements were maintained in the patients randomized to continue interferon. Stopping treatment was associated with an increase in serum ALT, log HCV-RNA, and hepatic inflammation back to baseline. After 30 months of treatment, mean fibrosis score declined from 2.5 to 1.7 and 80% of patients had histological improvement (P< 0.03). Discontinuation of interferon was associated with an increase in mean fibrosis score from 2.2 to 2.4 and worsening of hepatic histology in 30% of patients (P < 0.01). 

Conclusions: These data support the hypothesis that maintenance interferon may prevent histological progression of chronic HCV in patients who remain viremic.