This three-part, Phase 1 protocol will be the first clinical study of ABI-H2158. Parts 1 and 2 will be a Phase 1a, dose-ranging assessment of ABI-H2158 in healthy adult volunteers. If the dose-related safety, tolerability, and pharmacokinetics (PK) of ABI-H2158 in healthy volunteers are deemed satisfactory, then the study will advance to Part 3, a Phase 1b, dose-ranging assessment of ABI-H2158 in non-cirrhotic, CHB patients.

Healthy volunteers:

1. Male or female between 18 and 55 years old with a BMI of 18-34 kg/m2 with a minimum body weight of 45 kg
2. Must be in good health and not have any health condition which could interfere with the absorption, distribution or elimination of study drug, or with the clinical and laboratory assessments in this study

Chronic HBV patients:

Key Inclusion Criteria:

1. Male or female ≥ 18 and ≤ 65 years of age.

2. In good general health except for chronic HBV infection, documented by:

   1. Clinical history, physical exam and routine laboratory measurements without major or clinically significant findings
   2. Serologic profile consistent with chronic HBV infection • HBeAg-positive at Screening with HBV viral load ≥ 2× 105 IU/mL

3. Liver evaluation demonstrating the absence of bridging fibrosis or cirrhosis

Key Exclusion Criteria:

1. History or evidence of decompensated liver disease at any time prior to Screening
2. History or presence of any other clinically significant current medical conditions requiring ongoing pharmacological treatment.
3. Previous treatment with any investigational HBV antiviral treatments within the last 6 months, or previous treatment at any time with an investigational HBV antiviral treatment of the same class (core protein targeted therapies).
4. Previous treatment with a commercially approved HBV therapy within the last 6 months