Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan; Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan.
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. We 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.
We enrolled 268 consecutive treatment-naïve patients who underwent lamivudine therapy for chronic hepatitis B (CHB). Factors in terms of VB were analyzed by multivariate analysis.
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, HR 2.179, p=0.012) and HBV DNA levels ≥2000 IU/mL after 6 months of lamivudine therapy (HR 5.460, 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 ≥20000 IU/mL was the only risk factor associated with VB.
For CHB 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.