Hepatitis B surface antigen titer is a good indicator of durable viral response after off-treatment of entecavir for chronic hepatitis B

Abstract

Background/Aims: Definite guideline for stopping antiviral therapy for chronic hepatitis B (CHB) is not clarified yet. Previous studies suggested that HBsAg titer is correlated with covalently closed circular DNA. Therefore, HBsAg titer might be a good indicator for off-treatment. This study was performed to deter-mine the relationship between HBsAg titer and CHB relapse after off-treatment of entecavir (ETV).

Methods: Patients in whom ETV was discontinued after serum HBV with or without HBeAg clearance for more than 12 months and who measured HBsAg titer at off-treatment were enrolled. HBV DNA reactivation was defined as increase of serum HBV DNA level>2000 IU/mL, while CHB relapse was defined as HBV DNA reactivation and increase of serum ALT level>2XULN.

Results: Forty-four patients were enrolled. Age was 44.6±11.4 years and 28 patients (63.6%) were men. Baseline HBeAg was positive 25 patients (56.8%) and serum HBV DNA level was 6.8±1.3 log10 IU/mL. ETV was discontinued after 34.7±19.0 months of treatment. In HBeAg-positive CHB patients, ETV was discontinued after 37.0±20.2 months of treatment, which was 31.0±19.5 and 23.4±16.1 months after serum HBV DNA and HBeAg clearance, respectively. In HBeAg-negative CHB patients, ETV was discontinued after 31.6±17.4 months of treatment, which was 27.1±17.7 months after serum HBV DNA clearance. HBsAg titer at off-treatment was 3.0±1.0 log10 IU/mL, which was <2, 2~3, and >3 log10 IU/mL in 5 (11.4%), 11 (25.0%), and 28 (63.6%) patients, respectively. After off-treatment, HBV DNA reactivated in 38.7% and 66.2% and CHB was relapsed in 4.7% and 42.3% at 6 and 12 months after off-treatment, respectively. HBsAg titer at off-treatment was significantly associated with HBV DNA reappearance (P=0.010) and CHB relapse (P=0.010).

Conclusion: HBsAg titer at off-treatment is closely related with HBV reactivation and CHB relapse. HBsAg titer is considered as an excellent indicator of durable viral response after off-treatment.