Incidence and predictors of hepatitis B surface antigen seroclearance after cessation of nucleos(t)ide analogue therapy in hepatitis B e antigen–negative chronic hepatitis B

Hepatitis B surface antigen (HBsAg) loss is a rare event during nucleos(t)ide analogue (Nuc) therapy. Limited data suggest that stopping Nuc therapy may increase HBsAg loss rate in hepatitis B e antigen–negative patients. A large study was conducted to investigate this issue in more detail. Of the 1,075 hepatitis B e antigen–negative patients treated with Nuc for a median of 156 (61-430) weeks, 5 showed HBsAg seroclearance during treatment at an estimated annual incidence of 0.15%. Of the patients who remained HBsAg-seropositive, 691 (52.3 years old, 86% male, 44.6% cirrhosis) had stopped Nuc therapy by the Asian-Pacific Association for the Study of the Liver stopping rule and then were prospectively followed up. Baseline and on-treatment clinical and viral features, treatment duration, consolidation duration, time to undetectable hepatitis B virus DNA, time to normal alanine aminotransferase, end-of-treatment HBsAg, and HBsAg log reduction were compared between patients with and without HBsAg seroclearance after end of treatment. During a median off-therapy follow-up period of 155 (2-614) weeks, HBsAg seroclearance was confirmed in 42 patients. The 6-year cumulative incidence was 13% with an estimated annual incidence of 1.78%. Cox regression analysis showed that shorter time to undetectable hepatitis B virus DNA (<12 weeks), greater HBsAg reduction during therapy (>1 log₁₀), lower end-of-treatment HBsAg level (<100 IU/mL), patients with sustained response, and relapsers not retreated were factors for off-therapy HBsAg seroclearance. Conclusion: The incidence of HBsAg seroclearance after stopping Nuc was much higher than that during therapy and highest in patients without virologic and clinical relapse; patients with clinical relapse who remained untreated had a 7.34 times higher incidence of HBsAg clearance than those who received retreatment, suggesting that transient untreated clinical relapse may drive sufficient immune control to functional cure. (Hepatology 2017).