Sustained response rates were not affected by dose reductions, as long as patients received at least 60% of optimal doses of PEG-IFN and RBV.
About 50% of patients who are infected with genotype 1 hepatitis C virus (HCV) achieve sustained virologic responses (SVRs) during treatment with pegylated interferon (PEG-IFN) plus ribavirin (RBV). However, many patients require dose reductions because of side effects, which lower the SVR rate. In two retrospective studies, researchers examined the associations among cumulative exposure to PEG-IFN plus RBV, timing of dose reductions, and SVR.
One group analyzed data from two phase 3 trials in which 569 genotype 1 HCV-positive patients were treated with weekly PEG-IFN (180 μg) and daily RBV (1000–1200 mg). During these studies, doses of PEG-IFN could be reduced by as much as 50%, based on drops in absolute neutrophil counts; RBV doses could …