Differential roles of serum hepatitis B virus DNA and hepatitis B surface antigen level in predicting virological breakthrough in patients receiving lamivudine therapy

BACKGROUND AND AIM: The role of serum hepatitis B surface antigen (HBsAg) level in determining virological breakthrough (VB) for patients with hepatitis B virus (HBV) infection receiving lamivudine remains unclear. The study aimed to evaluate the impact of serum HBsAg levels on VB among patients receiving lamivudine therapy, especially in a setting of low HBV viral load. METHODS: Two hundred sixty-eight consecutive treatment-naïve patients who underwent lamivudine therapy for chronic hepatitis B were enrolled. Factors in terms of VB were analyzed by multivariate analysis. RESULTS: After a median treatment duration of 67.1 weeks, 102 patients had VB. Multivariate analysis showed that positive hepatitis B e antigen (HBeAg) (hazard ratio 2.165, P = 0.026) and HBV DNA levels ≥ 2000 IU/mL after 6 months of lamivudine therapy (hazard ratio 5.236, P = 0.001) were independent risk factors predicting VB. The cumulative VB rates stratified by HBeAg-positive and -negative at 3 years were 44.7% and 26.3%, respectively. At 3 years, the cumulative VB rates stratified by the HBV DNA < 2000 and ≥ 2000 IU/mL after 6 months of therapy were 25.5% and 79.4%, respectively. For HBeAg-positive patients with serum HBV DNA < 2000 IU/mL after 6 months of therapy, baseline HBsAg levels ≥ 20,000 IU/mL was the only risk factor associated with VB. CONCLUSIONS: For chronic hepatitis B patients treated with lamivudine, serum HBV DNA level > 2000 IU/mL after 6 months of therapy could predict subsequent VB. In patients with lower on-treatment viral load, baseline serum HBsAg level is associated with the emergence of VB, especially for those with serum positive HBeAg.