Predictive role of serum HBsAg and HBcrAg kinetics in patients with HBeAg-negative chronic hepatitis B receiving pegylated interferon-based therapy.

To investigate the role of serum hepatitis B core-related antigen (HBcrAg) kinetics in predicting long-term outcome of pegylated interferon (PEG-IFN)-based therapy in patients with HBeAg-negative chronic hepatitis B (CHB).121 Thai patients with HBeAg-negative CHB recruited from a previous randomized trial of 48-week PEG-IFN alone or combined with entecavir were enrolled. HBsAg and HBcrAg levels were serially examined. Paired biopsies at baseline and post-treatment were assessed for intrahepatic cccDNA.Persistent virological remission (PVR, defined by persistent HBV DNA <2,000 IU/mL), and HBsAg clearance at 3-year post-treatment were 29% (35/121) and 9% (11/121), respectively. Baseline HBcrAg correlated with HBV DNA and cccDNA but not with HBsAg. Baseline HBsAg, as well as HBsAg and HBcrAg declines were associated with PVR, while HBsAg decline was predictive of HBsAg clearance. High baseline antigen levels (HBsAg ≥3.4 log10 IU/mL plus HBcrAg ≥ 3.7 log10 U/mL) yielded high negative predictive values (NPVs) of PVR (45/50; 90%) and HBsAg clearance (50/50; 100%). At week 12, declines of HBsAg, HBcrAg and combined both antigens levels <0.5 log10 yielded NPVs for PVR of 90% (71/79), 82% (61/74) and 96% (48/50), respectively.Quantitative HBcrAg was significantly associated with cccDNA in HBeAg-negative CHB. This novel antigen, together with HBsAg, could identify patients with low probability of PVR and HBsAg clearance in long-term follow-up.