A Study Evaluating AHB-137 in Healthy Participants and Participants with Chronic Hepatitis B

Inclusion Criteria:

• Healthy participants are required to meet all the following inclusion criteria inorder to be enrolled in the study:

1. 18-65 years old male or female.

2. Body Mass Index (BMI) between 19 to 35 kg/m2 (inclusive) and body weight equalto or over 45 kg.

3. Participants' COVID-19 PCR test should be negative during screening.

4. Participants' COVID-19 Rapid Antigen Test (RAT) should be negative at check-in.

• CHB patients are required to meet all the following inclusion criteria in order tobe enrolled in the study:

1. Have given written informed consent (signed and dated) and any authorizationsrequired by local law and is able to comply with all study requirements.

2. Age 18 to 65 years old.

3. ALT ≤ 5 ULN for CHB patients recruited to Part C; ALT ≤ 2 ULN for CHB patientsrecruited to Part D.

4. CHB patients who have documented chronic HBV infection equal to or above 6months prior to screening. Otherwise, CHB patients need to be HBsAg positiveand IgM HBcAb negative.

5. CHB patients participating in Part D should have been on commercially availableHBV OAV treatment(s) for at least 6 months with no change in regimen for 3months prior to screening. HBV DNA under limit of quantification (LOQ) atScreening.

6. Both HBeAg positive and negative CHB patients can be recruited to Part C of thestudy. Only HBeAg negative CHB patients can be recruited to Part D of thestudy.

7. COVID-19 RAT test should be negative at check-in.

Exclusion Criteria:

• Healthy participants are required to not meet any of the following exclusioncriteria in order to be enrolled in the study:

1. Pregnant (positive pregnancy test) or lactating women. Male participantswithout using proper contraceptives (e.g. condom) with partners who arepregnant or lactating.

2. History or symptoms of any clinically significant gastrointestinal, renal,hepatic, bronchopulmonary, neurological, psychiatric, cardio-vascular,endocrinological, hematological or allergic disease, metabolic disorder, canceror cirrhosis.

3. Personal history of congenital long QT syndrome or family history of suddencardiac death.

4. Any confirmed significant allergic reactions (urticaria or anaphylaxis) againstany drug, or multiple drug allergies (non-active hay fever is acceptable).

5. Any clinically significant concomitant diseases or condition that couldinterfere with, or treatment of which might interfere with, the conduct of thestudy, or that would, in the opinion of the Investigator, pose an unacceptablerisk to the participant in this study.

6. Clinically relevant electrocardiogram (ECG) abnormalities on screening ECG.

7. ECG with QRS and/or T-wave judged to be unfavorable for a consistently accurateQT measurement.

8. Creatinine clearance (CrCl) cutoff ≤ 60 ml/min (using the Cockcroft-Gaultformula).

9. Positive test at screening of any of the following: hepatitis A (HAV IgM Ab),hepatitis B (HBsAg), hepatitis C (HCV RNA or HCV Ab), human immunodeficiencyvirus 1 and 2 (HIV Ab), or TP-Ab.

10. Any other clinically significant abnormalities in laboratory test results atscreening. In the case of uncertain or questionable results, tests performedduring screening may be repeated before randomization to confirm eligibility.

11. History of bleeding diathesis or coagulopathy.

CHB patients are required to not meet any of the following exclusion criteria in order to be enrolled in the study:

1. History of liver cirrhosis and/or evidence of cirrhosis as determined by any 1 ofthe following:

2. Liver biopsy (i.e., Metavir Score F4) within 2 years of screening, or

3. FibroScan > 12 KPa, within 12 months of screening, or

4. AST-to-Platelet Index (APRI) > 2 and FibroSure result > 0.7 within 12 months ofscreening. For patients without a test for cirrhosis in the above timeframes, FibroScan, orAPRI and FibroSure, may be performed during the screening period to rule outcirrhosis History of liver failure as evidenced by ascites, hepatic encephalopathy,and/or gastric or esophageal varices.

5. History of liver disease other than hepatitis B.

6. Co-infection with TP, HCV, HIV, or hepatitis D virus (HDV).

7. Body mass index >35 kg/m2 .

8. History or suspected presence of vasculitis .

9. Diagnosed hepatocellular carcinoma or suspected hepatocellular carcinoma asevidenced by screening alpha-fetoprotein ≥200 ng/mL. If the screeningalpha-fetoprotein is ≥50 ng/mL and <200 ng/mL, the absence of liver mass must bedocumented by imaging within 6 months before randomization.

10. Clinically relevant electrocardiogram (ECG) abnormalities on screening ECG.

11. Screening laboratory results as follows, or any other clinically significantabnormalities in screening laboratory values that would render a patient unsuitablefor inclusion.

12. ALT > 5 x ULN for Part C or > 2 x ULN for Part D

13. Total bilirubin > 1.25 x ULN

14. Serum albumin < 3.4 g/dL

15. International normalized ratio of prothrombin time > 1.25

16. Platelet count <140 x 10^9/L

17. Hemoglobin <12.0 g/dL for males and <11.0 g/dL for females

18. White blood cell count <3.0 k/mm3

19. Serum creatinine >1.1 x ULN

20. Urine protein/creatinine ratio ≥0.2 mg/mg. In the event of a ratio above thisthreshold, eligibility may be confirmed by a quantitative total urine proteinmeasurement of <150 mg/24 hour

21. Positive test (including trace) for blood on urinalysis. In the event of apositive test, eligibility may be confirmed with urine microscopy showing <5red blood cells per high power field

22. Clinically significant abnormalities and/or poorly controlled medical conditions (e.g. Cardiovascular, pulmonary, metabolic disease) in the opinion of theinvestigator.

23. History of bleeding diathesis or coagulopathy.

24. History of extrahepatic disorders possibly related to HBV immune complexes (e.g.,glomerulonephritis, polyarteritis nodosa) .

25. Active infection other than HBV, requiring systemic antiviral or antimicrobialtherapy that will not be completed prior to Study Day 1.