Effectiveness of Extending Treatment Duration in Therapy with Pegylated Interferon and Ribavirin for Genotype 2 Hepatitis C Virus Infection

The effectiveness of extending treatment duration as response guided therapy was previously reported for chronic hepatitis C (CHC genotype 1 but is still controversial for genotype 2. The present study is a retrospective cohort study to investigate the effectiveness of extending treatment duration in ther‑ apy with pegylated interferon and ribavirin for patients with CHC genotype 2 by focusing on the tim‑ ing at which patients obtained undetectable HCV RNA. A total of 306 patients who obtained undetect‑ able HCV RNA by week 24 of treatment and completed 24 weeks of treatment were enrolled. Rapid virological response (RVR to standard therapy was achieved by 122 patients (51ｵ and 89ｵ of them obtained sustained virological response (SVR while 69ｵ of non‑RVR patients achieved SVR. Non‑ RVR patients with undetectable HCV RNA at week 8 and insufficient adherence＜80ｵ pegylated interferon and ribavirin during the first 24 weeks significantly improved their SVR rate by extended therapy. Among patients receiving extended therapy drug adherences did not differ between SVR and non‑SVR patients indicating that extending treatment duration might compensate for insufficient antiviral effects due to insufficient drug adherences. This finding might be useful in creating a guide‑ line for extending treatment duration for patients with CHC genotype 2.