The objective of this study is to evaluate the safety and efficacy of ASC22 in the treatment of chronic hepatitis B after single and multiple drug administration.

The study consists of two parts: the ASC22 single-dose IIa study and the ASC22 multi-dose IIb study. The IIa study consists of 3 cohorts of 0.3mg/kg, 1.0mg/kg and 2.5mg/kg, and the IIb study consists of 2 cohorts of 1.0mg/kg and 2.5mg/kg. The objective is to evaluate the safety, tolerance and efficacy of ASC22 in patients with chronic hepatitis B (CHB), and to provide a guidance for the determination of dosage regimen.

Inclusion Criteria:

1. 18-65 years old (including boundary value), gender unlimited；
2. Chronic hepatitis B patients with clear diagnosis of Hematology, etiology and clinical (for example: HBsAg positive for more than 6 months);
3. HBV-DNA turns negative after treatment with nucleoside (acid) drugs;
4. cohort1-5:HBsAg≤ 10000 IU/mL; cohort6: HBsAg≤ 100 IU/mL;
5. HBeAg negative;
6. The fertile female subjects or the fertile male subjects agreed to take contraceptive measures from 7 days before the first administration until 24 weeks after the end of the administration cycle of ASC22. The serum pregnancy test of fertile female subjects must be negative within 7 days before the first administration.

Exclusion Criteria:

1. Patients with hepatitis a, hepatitis c (HCV RNA>15IU/L), hepatitis d or HIV infection; Patients with other active infections (e.g., respiratory tract infection, urinary tract infection and herpes simplex, cytomegalovirus, epstein-barr virus);
2. Fibrosis stage: Cirrhosis, portal hypertension, or advanced fibrosis (defined as Fibroscan≥9.5kPa or ARFI≥1.81m/sec or Fibrosis-4 (FIB-4)≥3.25 or METAVIR F≥3);
3. Liver cancer patients or blood AFP>1×ULN;
4. cohort1-5：Patients who received interferon therapy within 6 months before the first administration; cohort6: Patients who received interferon therapy before the first administration;
5. Patients receiving immunosuppressive therapy within 3 months before the first administration (except interferon);
6. The investigator judges that the participants are not suitable for this study.