Quantitative hepatitis B surface antigen titres in Chinese chronic hepatitis B patients over 4 years of entecavir treatment.

BACKGROUND The clinical value of quantitative hepatitis B surface antigen (qHBsAg) titre in patients taking nucleotide/nucleoside analogues (NAs) is still controversial. This study aims to investigate the dynamic changes of qHBsAg titres and their significance for predicting virological response (VR) and serological response (SR) to long-term entecavir (ETV) treatment. METHODS A total of 48 ETV-naive patients were enrolled and followed prospectively for 4 years, 32 of whom were hepatitis B e antigen (HBeAg)-positive at baseline. Serum alanine aminotransferase (ALT), qualitative HBV serological markers and HBV DNA were detected; qHBsAg titres were measured using Elecsys(®) HBsAg II Quant Assay (Roche Diagnostics, Penzberg, Germany). RESULTS The mean baseline HBV DNA and qHBsAg were 7.51 log10 copies/ml and 3.78 log10 IU/ml, respectively. After 48 months of ETV treatment, the rates of VR (<291 copies/ml), ALT normalization and SR (HBeAg/antibody to HBeAg [anti-HBe]) were 89.6% (43/48), 89.6% (43/48) and 34.4% (11/32), respectively. There was a decrease in qHBsAg titres from baseline to month 48, ranging from 3.78 to 3.10 log10 IU/ml. The greatest decrease of qHBsAg was observed in the first 3 months of treatment (0.47 log10 IU/ml), which was significantly correlated with corresponding HBV DNA decreases (3.89 log10 copies/ml; P=0.032). By using receiver operating characteristic (ROC) curve analysis, qHBsAg titres at baseline (area under the curve [AUROC]=0.647) and 3 months after treatment (AUROC=0.586) had poor power in predicting 48-month VR; qHBsAg titres at baseline (AUROC=0.779) and 3 months after ETV treatment (AUROC=0.658) had poor power in predicting 48-month SR in patients who were HBeAg-positive at baseline. Additionally, the decrease of qHBsAg in the first 3 months of treatment also had poor power in predicting either 48 month VR or SR. CONCLUSIONS ETV is efficacious in NA-naive patients, and qHBsAg titres decreased significantly in the first 3 months of ETV treatment. However, qHBsAg titre was not a good predictor of 4-year VR and HBeAg/anti-HBe SR in this cohort.