Optimizing the dose and duration of therapy for chronic hepatitis C.

Recent studies indicate that antiviral treatment with pegylated interferon alfa and ribavirin for hepatitis C can be individualized based on viral and host characteristics and the pattern of virologic response during the initial months of antiviral treatment. Patients with a low initial viral load who demonstrate a rapid virologic response to antiviral therapy may be treated with a shorter duration of therapy and are less sensitive to reduced dosing of ribavirin. Patients with delayed virologic response will require a longer duration of therapy - up to 72 weeks for patients with genotype 1 - in order to optimize chances of a sustained virologic response. Patients who were nonresponders or relapsed after an acceptable course of antiviral therapy may be retreated using a more intensive regimen and/or a longer duration of therapy. Previous nonresponders to pegylated interferon alfa and ribavirin are less likely to respond to retreatment unless they demonstrate a virologic response within the first three months of retreatment, lack advanced fibrosis, and can tolerate a more intensive and/or lengthier treatment. Individualized treatment based on viral genotype, viral load, the presence of advanced fibrosis, and initial virologic response can improve therapy for some patients and save resources in others.