Biomarkers Guided Stopping NAs Treatment

Key Inclusion Criteria: * 18-65 years of old, male or female * Chronic hepatitis B patients * Received continuous ETV, TDF or TAF therapy for at least 1 year prior to screening and at screening * For patients with Hepatitis B e Antigen (HBeAg)-positive at the beginning of NAs therapy, documented hepatitis B virus \<20 IU/mL, HBeAg seroconversion and ALT normalization for at least 1 year prior to screening and at screening * For patients with HBeAg-negative at the beginning of NAs therapy, documented hepatitis B virus \<20 IU/mL, and ALT normalization for at least 3 year prior to screening and at screening * \<= 9 kPa on Fibroscan assessment * qHBsAg \<200 IU/mL within 24 weeks prior to screening * HBV RNA or HBcrAg negativity within 24 weeks prior to screening Key Exclusion Criteria: * Experience of IFN treatment within 1 year prior to screening * Known cirrhosis * History of decompensated liver disease * History of clinical hepatic decompensation in the judgement of the investigator * Evidence of hepatocellular carcinoma * Serological evidence of coinfection with human immunodeficiency virus (HIV), hepatitis C virus, or hepatitis D infection * Known hypersensitivity to TDF, its metabolites, or formulation excipients * History of malignant disease * Lactating females * Females wishing to became pregnant during the duration of the study * Subjects participating in another clinical trial