Changes of HBsAg and HBV DNA levels in C hinese chronic hepatitis B patients after 5 years of entecavir treatment

Background and Aim Hepatitis B surface antigen ( HBsAg ) kinetics during long‐term entecavir therapy has not been well investigated. Methods We described the cumulative serologic, virologic, and biochemical outcomes and the occurrence of signature entecavir mutations among 222 C hinese treatment‐naïve chronic hepatitis B ( CHB ) patients receiving entecavir for up to 5 years. Results The median rate of HBsAg reduction over 5 years was 0.125 log IU /mL/year. Patients with high baseline HBV DNA levels (≥ 8 log copies/mL or ≥ 7.3 log IU /mL), when compared with those with baseline hepatitis B virus ( HBV ) DNA < 7.3 log IU /mL, had a significantly greater median rate of HBsAg reduction (0.178 and 0.102 log IU /mL/year, respectively, P  < 0.001). The difference in HBsAg decline was most prominent in the first year (0.324 and 0.062 log IU /mL/year, respectively, P  < 0.001). Greater median rates of HBsAg reduction were also found in hepatitis B e antigen ( HBeAg )‐positive patients when compared with HBeAg ‐negative patients (0.144 and 0.098 log IU /mL/year, P  = 0.015), and in patients with high baseline HBsAg levels (≥ 3 log IU /mL), when compared with patients with low baseline HBsAg < 3 log IU /mL (0.131 and 0.045 log IU /mL/year, respectively, P  = 0.001). The 5‐year cumulative rate of HBV DNA undetectability (< 20 IU /mL) was 97.1%. There were two cases of entecavir resistance, resulting in a 5‐year cumulative resistance rate of 1.2%. Conclusion I n contrast to the profound HBV DNA suppression, long‐term entecavir treatment achieved only a slow decline in serum HBsAg . Although certain patient subgroups exhibit a more rapid HBsAg reduction, additional therapeutic agents are needed to increase the chance of HBsAg seroclearance in CHB .