AB-10-8005 is a single-center, open-label Phase II clinical study to evaluate the antiviral activity and immune responses of AHB-137 injection in participants with CHB treated with nucleos (t) ide analogues.

The study is to evaluate the antiviral activity and immune response of AHB-137 injection in participants with CHB treated with nucleos(t)ide analogues. The study is proposed to enroll 20-30 patients, with a total study duration of approximately 56 weeks per participants, including a screening period (up to 4 weeks), a clinical study lead-in period (approximately 4 weeks), an AHB-137 treatment period (24 weeks) and a follow-up period (24 weeks).

Inclusion Criteria:

• Voluntarily participated in the study and signed an informed consent form;
• Aged between 18 and 55 years at the time of signing the informed consent form;
• Body mass index (BMI) within the range of 18-30 kg/ m2;
• HBeAg negative or positive at screening;
• HBsAg or HBV DNA positive for at least 6 months;
• Have been on continuous nucleos(t)ide analogues antiviral therapy for more than 6 months prior to screening;
• 100 IU/mL < HBsAg ≤ 3000 IU/mL and HBV DNA < 100 IU/mL at screening;
• Alanine aminotransferase (ALT) ≤ 2 × upper limit of normal (ULN);
• Effective contraception as required.

Exclusion Criteria:

• Clinically significant abnormalities other than a history of CHB infection;
• Concomitant clinically significant other liver diseases;
• Any serious infection other than CHB infection requiring intravenous anti-infective therapy within 1 month prior to screening;
• Active hepatitis C, Human immunodeficiency virus (HIV) positive, syphilis positive;
• Liver stiffness value (LSM) > 9.0 kPa at screening;
• Diagnosis or suspicion of hepatocellular carcinoma, or alpha-fetoprotein (AFP) concentration ≥ 20 ng/mL at screening;
• Participants with confirmed or suspected hepatic decompensated hepatitis B cirrhosis;
• Liver biopsy at screening assessed severity of activity ≥ G3 grade and/or fibrosis reaching S4 stage;
• History of extrahepatic disease possibly related to HBV immune status;
• Ongoing or taking any immunosuppressive medication within 3 months prior to screening. Those who have used immunomodulators and cytotoxic drugs within 6 months prior to the first dose, or have a history of vaccination within 1 month prior to screening or have a live vaccination plan during the trial; Continuous use of traditional Chinese medicine for more than 2 months within 1 year prior to screening, or within 1 month prior to screening; Ongoing use of anticoagulants, bleeding tendency or coagulopathy, or conditions that, in the opinion of the investigator, increase the risk of liver biopsy;
• Receiving or using any interferon-containing therapy within 12 months prior to screening;
• History of malignancy within 5 years prior to screening or being evaluated for possible malignancy;
• Suspected history of allergy to any component of the study drug, or allergic constitution (multiple drug and food allergy, and judged by the investigator to be clinically significant);
• Major trauma or major surgery within 3 months prior to screening, or planned surgery during the study;
• Donation or blood loss ≥ 400 mL, or received blood transfusion within 12 weeks prior to screening; Or blood donation or blood loss ≥ 200 mL within 1 month prior to screening;
• Participants who are participating in another clinical trial, or have not undergone a protocol-specified washout period prior to this study;
• Received any antisense oligonucleotides (ASO) or using any small molecule interfering ribonucleic acid (siRNA) drug within 12 months prior to screening;
• Participants with abnormal thyroid function judged by the investigator to be ineligible for enrollment;
• Obviously abnormal laboratory test results;
• History of vasculitis or signs and symptoms of underlying vasculitis;
• Any other circumstance or condition that, in the opinion of the investigator, the participants are inappropriate for participation in the study.