Early quantification of HCV core antigen may help to determine the duration of therapy for chronic genotype 2 or 3 HCV infection.

The aim of the present study was to evaluate the utility of hepatitis C virus (HCV) core antigen (coreAg) assessment for the identification of candidates for short-term therapy. Plasma samples from HCV genotype 2 or 3-infected patients participating in the NORDynamIC trial (n=382) comparing 12 and 24 weeks of combination treatment with pegylated interferon-α2a and a fixed dose of 800 mg ribavirin daily were analyzed for coreAg. Among the 126 patients (33% of the intention-to-treat population) achieving HCV coreAg levels in plasma below 0.2 pg/mL when assayed on treatment day 3, sustained viral response (SVR) rates of 86% and 84% were achieved in the 12- and 24-week arms, respectively. Similarly, among patients having received at least 80% of the target dose of both pegylated interferon α-2a and of ribavirin for at least 80% of the target treatment duration (per-protocol analysis), the SVR rates were 89% and 95%, respectively. Twelve weeks of combination treatment may be sufficient for genotype 2 or 3-infected patients achieving HCV coreAg levels below 0.2 pg/mL by day 3, signaling a rapid clearance of HCV viremia.

Ribavirin plasma concentration is a predictor of sustained virological response in patients treated for chronic hepatitis C virus genotype 2/3 infection.

In hepatitis C virus (HCV) genotype 1 infection, the likelihood of obtaining sustained virological response (SVR) is associated with higher ribavirin exposure. Such an association has not been demonstrated for HCV genotype 2/3 infection, where a fixed 800 mg daily dosing of ribavirin is generally recommended. The primary aim of this study was to investigate the correlation between ribavirin concentration at day 29 and therapeutic response in patients with HCV genotype 2/3 infection. A total of 382 patients were randomized to 12 or 24 weeks of treatment with pegylated interferon-alfa 2a 180 µg weekly and 800 mg ribavirin daily. Trough plasma concentration of ribavirin was measured at day 29 and week 12 and the primary outcome was SVR (HCV-RNA undetectable 24 weeks after treatment). Of the 382 patients, 355 had a ribavirin concentration available at day 29. SVR was 84% among patients with a ribavirin concentration ≥2 mg/L at day 29 compared to 66% in those with concentrations <2 mg/L (P = 0.002). The corresponding figures in the 12-week treatment group were 74% and 57% (P = 0.12), and in the 24-week treatment group 91% and 75% (P = 0.02), respectively. In a multivariate analysis, ribavirin concentration at day 29 was an independent predictor of SVR (P = 0.002). In conclusion, a higher plasma ribavirin concentration is associated with an increased likelihood of achieving SVR in HCV genotype 2/3 infection. Individualization of ribavirin dosing may be helpful in improving outcome, especially in the presence of unfavourable baseline characteristics. This, however, requires evaluation in a prospective trial.