Abstract
In the treatment of chronic infection with genotype 1 hepatitis C virus, good compliance to PEG-IFN treatment schedule is extremely important to achieve virological response. With the objective of assuring the administration of adequate doses, we examined whether the dose reduction according to the criteria in the package insert of PEG-IFN α-2b is really needed or not. In the past 10 years after approval in Japan , IFN α-2b has been administered, as a rule, without dose reduction. No significant difference is observed following the administration of 6 MIU of IFN α-2b and 1.5 μg/kg of PEG-IFN α-2b in the change in blood cell parameters. To assure safety when PEG-IFN α-2b is administered without dose reduction, the correlation between nadir values during the treatment period and the weekly or monthly measurement values was examined. The results indicated that it is possible to predict nadir values during the treatment period from measurement value after one week of treatment (Platelet: r'2=0.6011, P<0.0001, Neutrophil: r'2=0.6801, P<0.0001). No safety problems were observed if we did not strictly follow the dose reduction of PEG-IFN α-2b settled in the package insert. To achieve improvement in efficacy with PEG-IFN α-2b plus ribavirin combination treatment, early reduction of the dose of PEG-IFN α-2b should be avoided while conducting periodic monitoring of blood cell parameters.
