The pharmacokinetics and pharmacodynamics of standard interferon alfa-2a and interferon alfa-2b are substantially altered by pegylation. The size, geometry, and site of attachment of the PEG moiety affect the pharmacokinetics and pharmacodynamics as evidenced by the different absorption, volume of distribution, and clearance of the linear 12-kDa peginterferon alfa-2b and the branched 40-kDa peginterferon alfa-2a. Despite these differences, the clinical efficacy, safety, and tolerability of the 2 peginterferons are similar. However, evidence exists that peginterferon alfa-2 plus ribavirin is associated with small but significantly higher sustained virological response rates compared with peginterferon alfa-2b. This article discusses the pharmacokinetics and pharmacodynamics of the 2 peginterferons and their combination with ribavirin.
Published by Elsevier Inc.