Background: The "response-guided therapy" based on response of hepatitis C virus (HCV) during antiviral combination therapy with peginterferon and ribavirin is important for patients with HCV genotype 1. However, the sensitivity of previous assays for serum HCV RNA is limited.
Objectives: We evaluated the changes in serum HCV RNA during the combination therapy using a novel method for measurement based on real-time PCR.
Study design: Changes in serum HCV RNA during the combination therapy were reanalyzed using TaqMan PCR assay in 144 patients with chronic HCV genotype 1b infection who underwent the therapy under HCV RNA monitoring with the Amplicor Monitor assay. Treatment duration was elongated from 48 weeks to 72 weeks in 17 patients based on the time when serum HCV RNA became negative.
Results: In 9 of 144 (6.3%) patients, serum HCV RNA transiently appeared again on the TaqMan PCR assay after having previously become negative. At the point of reappearance, the Amplicor Monitor assay gave a negative result in all patients, and no flare of alanine aminotransferase activity was observed. Each of the 9 patients achieved an end-of-treatment response but relapsed after the end of treatment, including 3 patients in whom the treatment duration was elongated to 72 weeks.
Conclusions: Attention should be paid to this phenomenon in the antiviral treatment for patients with HCV infection. The transient reappearance of HCV RNA in the serum indicates a high likelihood of relapse, and is likely to be missed without frequent measurements by a sensitive detection method.