Customizing treatment to patient populations.

Combination treatment with pegylated interferon plus ribavirin is the most effective therapy for patients with chronic hepatitis C virus (HCV); however, responses are less than optimal in some subpopulations of patients. Emerging insights are suggesting that viral kinetics can be used to predict response. The rapidity of response has been shown to be a more important predictor of sustained virologic response than the duration of therapy. In patients with HCV genotype 2 or 3, shorter durations of treatment might be sufficient in rapid responders and could minimize the risk of toxic effects. Weight-based dosing of ribavirin has emerged as another important consideration. This strategy seems to be most important for difficult-to-treat patients with HCV genotype 1 or advanced fibrosis, and for African-Americans, and is possibly important for patients who have genotype 3 and a high viral load. Re-treatment of nonresponders with interferon-based therapy has been associated with low rates of sustained virologic response. Consensus interferon might offer a new option for patients who do not achieve an early treatment response to standard or pegylated interferon plus ribavirin.