Low pretreatment serum HBsAg level and viral mutations as predictors of response to PEG-interferon alpha-2b therapy in chronic hepatitis B

Background: Viral genomic mutations have become increasingly recognized as being associated with the outcome of chronic HBV infection. However, the role of viral mutations as a predictor of response to pegylated-interferon (PEG-IFN) therapy has so far remained unclear. Study design: Viral mutations in the enhancer II/basal core promoter (BCP)/precore and the pre-S regions were characterized by direct sequencing in pretreatment serum samples of 50 patients with chronic hepatitis B (33 HBeAg-positive and 17 HBeAg-negative), who were treated for 48 weeks with PEG-IFN alpha-2b. Results: Sustained virological response at 48 weeks post treatment, defined as HBeAg seroconversion and HBV DNA < 2000 IU/mL for HBeAg-positive patients, and HBV DNA < 200 IU/mL for HBeAg-negative patients, was achieved in 12 (36.4%) and 6 (35.3%) of HBeAg-positive and HBeAg-negative patients, respectively. Response to PEG-IFN therapy correlated to low pretreatment HBsAg level but did not correlate with HBV genotype, pretreatment alanine transaminase and HBV DNA levels. In HBeAg-positive hepatitis, PEG-IFN response correlated with the appearance of double BCP mutations (A1762T/G1764A) at baseline (P=0.041). In the HBeAg-negative group, response to PEG-IFN therapy was associated with the presence of pre-S mutation/deletions (P=0.028). Multivariate analysis identified low pretreatment HBsAg level as an independent factor associated with SVR in both groups. Conclusions: Pretreatment quantitative HBsAg determination is useful for predicting response to PEG-IFN therapy. The presence of double BCP and pre-S mutation/deletions at entry may be associated with a high rate of antiviral response in HBeAg-positive and HBeAg-negative hepatitis, respectively. (C) 2009 Elsevier B.V. All rights reserved.