Dynamics of Hepatitis C Virus Monitored by Real-Time Quantitative Polymerase Chain Reaction During First 2 Weeks of IFN- β Treatment Are Predictive of Long-Term Therapeutic Response

The relation between the change in hepatitis C virus (HCV) RNA levels at the start of interferon-β (IFN-β) treatment and the long-term therapeutic response remains poorly defined. In 20 patients with chronic hepatitis C who received IFN-β (total dose 126-756 MU), the changes in serum HCV RNA during the first 2 weeks of therapy were monitored by real-time quantitative polymerase chain reaction (PCR). The serum HCV RNA level decreased rapidly during the first 24 h of therapy (first phase) and more slowly thereafter (second phase), with a mean exponential decay rate of 1.17 log₁₀/day and 0.37 log₁₀/day, respectively. Three patients had a sustained virologic response, 10 patients had a transient response, and 7 patients had no response. The differences in the rate of first-phase viral decline among the three groups were not significant (p = 0.21), but the differences in the rate of second-phase viral decline were significant (p = 0.0021). The mean decay rate between the end of the first 24 h and day 14 was 0.96 ± 0.43 log₁₀/day in sustained responders, 0.39 ± 0.30 log₁₀/day in transient responders, and 0.13 ± 0.09 log₁₀/day in nonresponders. We conclude that during the first 2 weeks of therapy, changes in serum HCV RNA levels as monitored by real-time quantitative PCR can be used to predict the long-term response to treatment with IFN-β.