Pretreatment serum HBsAg-to-HBV DNA ratio predicts a virologic response to entecavir in chronic hepatitis B

BACKGROUND/AIMS Decay of hepatitis B surface antigen (HBsAg) titers has previously been shown to be predictive of a virologic response (VR), especially during peginterferon-alpha therapy. However, the role of HBsAg levels in predicting a VR to nucleos(t)ide analog therapy has not yet been established. In this study we sought to determine whether the VR can be predicted from HBsAg titers in nucleos(t)ide-naive chronic hepatitis B (CHB) patients treated with entecavir. METHODS CHB patients who started entecavir as an initial antiviral therapy were enrolled in this study. Serum hepatitis B virus (HBV) DNA, HBsAg, and alanine aminotransferase levels were measured every 3 months during treatment. A VR was defined as undetectable serum HBV DNA titer by real-time PCR assay (<60 IU/mL). RESULTS Fifty-two patients were enrolled, and the median duration of treatment was 26 months (range 7-35 months). Forty-five patients achieved a VR; the cumulative VR rates at 3, 6, 12, and 24 months were 40%, 71.2%, 81.5%, and 88%, respectively. Baseline HBV DNA levels were significantly lower in patients with VR, whereas the HBsAg levels did not differ significantly between patients with or without VR. In a univariate analysis the cumulative VR rate was significantly higher in HBeAg negative patients and patients with an HBsAg/HBV DNA ratio above 0.56. However, in a multivariate analysis only an HBsAg/HBV DNA ratio above 0.56 was an independent predictor of VR (P=0.003). The area under the receiver operating characteristic curve was larger for the HBsAg/HBV DNA ratio than for either HBV DNA or HBsAg. CONCLUSIONS Pretreatment HBsAg/HBV DNA ratio can predict a long-term VR to entecavir therapy in nucleos(t)ide-naive CHB patients.