Association of on-treatment serum hepatitis B surface antigen level with sustained virological response to nucleos(t)ide analog in patients with hepatitis B e-antigen positive chronic hepatitis B

Aim: This study evaluated the on‐treatment serum hepatitis B surface antigen (HBsAg) level during nucleos(t)ide analog (NUC) therapy and the correlation with off‐treatment sustained virological response (SVR). Methods: Fifty‐one consecutive patients with hepatitis B e‐antigen (HBeAg) positive chronic hepatitis B who achieved HBeAg loss/seroconversion after NUC therapy and completed 12 months or more of additional therapy were included. Serum HBsAg and hepatitis B virus (HBV) DNA levels were determined at baseline, 3, 6, 9 and 12 months, and at the end of treatment. SVR was defined as HBV DNA levels of less than 10 000 copies/mL until 6 or 12 months off‐treatment without reappearance of HBeAg. Results: Twenty‐two (43.1%) and 13 (25.5%) patients maintained SVR at 6 and 12 months off‐treatment, respectively. In univariate analyses, a decline of HBsAg of 0.5 log10 IU/mL or less at 6 months (P = 0.006) and 12 months (P = 0.013), the mean change in HBsAg level at 6 months (P = 0.024), and lamivudine or entecavir treatment (P = 0.019) were significant predictive factors for SVR at 6 months off‐treatment. A decline of HBsAg of 0.5 log10 IU/mL or less at 6 months and lamivudine or entecavir treatment were independent factors on multivariate analyses (odds ratio [OR], 16.67; 95% confidence interval [CI], 1.86–142.86 [P = 0.012]; and OR, 14.83; 95% CI, 1.18–185.73 [P = 0.036]; respectively). Conclusion: On‐treatment serum HBsAg level predicted early off‐treatment SVR to NUC therapy in patients infected with genotype C.