This is a Phase 2 study to evaluate efficacy and safety of 48 weeks of oral once daily monotherapy with ALG-000184 versus tenofovir disproxil fumarate (TDF) for chronic HBV infection.

This is a randomized, double-blind, active-controlled, multicenter Phase 2 study to evaluate the efficacy and safety of 48 weeks of oral (PO) once daily (QD) monotherapy with ALG-000184 versus TDF in treatment naive (TN) or currently not treated (CNT) HBeAg-positive and HBeAg-negative subjects with chronic HBV infection (inclusive of chronic infection and/or chronic hepatitis).

A total of approximately 200 eligible subjects will be enrolled across 2 study parts. Part 1 will be an evaluation of HBeAg-positive subjects with chronic HBV infection and Part 2 will be an evaluation of HBeAg-negative subjects with chronic HBV infection. Each study part will consist of a main study and an exploratory liver biopsy sub-study.

Following the 48-week double-blind dosing period (Week 48), all participating subjects (in Parts 1 and 2) will be allowed to roll over into a 48 week (i.e., Week 48-96) open-label treatment extension period where they will all receive ALG-000184 monotherapy.

Key Inclusion Criteria:

1. Male or female between 18 and 65 years of age, with body mass index (BMI) of 18.0 to 35.0 kg/m2 (or minimun age by local regulatory requirements).

2. HBeAg-positive and anti-HBeAg (HBeAb) negative (Part 1); or HBeAg-negative (Part 2).

3. HBsAg ≥LLOQ.

4. HBV DNA ≥20,000 IU/mL.

5. A history of a clinical diagnosis of chronic HBV infection AND an ALT values of ≤8×ULN during screening.

6. Must have the following chronic hepatitis B virus infection treatment status at screening:

   1. Have never received treatment with HBV antiviral medicines (NA, interferon) or investigational anti-HBV agents including a CAM [i.e., Treatment Naïve (TN) subjects], OR
   2. Have not been on treatment with approved (NA, interferon) or investigational HBV antiviral medicines (e.g., antisense oligonucleotides or small interfering RNAs) within 6 months or 5 half-lives (whichever is longer) prior to randomization (i.e., Currently Not Treated (CNT) subjects).

Key Exclusion Criteria:

1. Co-infection with hepatitis A, C, D, E or HIV or any evidence of clinically significant liver disease of non-HBV etiology.

2. Positive for anti-HBs antibodies.

3. History or current evidence of cirrhosis.

4. Liver fibrosis that is classified as Metavir Score ≥F3 liver disease.

5. History of, or current evidence of, hepatic decompensation.

6. Evidence of hepatocellular carcinoma (HCC) on a liver ultrasound.

7. Having received an investigational medicinal product or device within 4 weeks (or 5 half-lives, whichever is longer) before the planned first dose of study drug

8. Exclusionary screening laboratory values include:

   1. Aspartate aminotransferase (AST) >8×ULN,
   2. Bilirubin (total, direct) >1.2×ULN (unless Gilbert's syndrome is suspected)
   3. International Normalization Ratio (INR) >1.2×ULN