Study of Bepirovirsen in Nucleos(t)Ide Analogue-treated Participants With Chronic Hepatitis B (B-Well 1) (B-Well 1)

Inclusion Criteria: Participants who have documented chronic HBV infection ≥6 months prior to screening and currently receiving stable NA therapy defined as no changes to their NA regimen from at least 6 months prior to Screening and with no planned changes to the stable regimen over the duration of the study. Plasma or serum HBsAg concentration >100 IU/mL, but no greater than ≤3000 IU/mL. Plasma or serum HBV DNA concentration must be adequately suppressed, defined as plasma or serum HBV DNA <90 IU/mL. Alanine aminotransferase (ALT) ≤2 × upper limit of normal (ULN). Participants who are willing and able to cease their NA treatment in accordance with the protocol. Exclusion criteria: - Clinically significant abnormalities, aside from chronic HBV infection in medical history (e.g., moderate severe liver disease other than chronic HBV, acute coronary syndrome within 6 months of screening, major surgery within 3 months of screening, significant/unstable cardiac disease, uncontrolled diabetes, bleeding diathesis or coagulopathy) or physical examination. Co-infection with: a) Current history of Hepatitis C infection or participants that have been cured for <12 months at the time of screening b) Human immunodeficiency virus (HIV), c) Hepatitis D virus. History of or suspected liver cirrhosis and/or evidence of cirrhosis. Diagnosed or suspected hepatocellular carcinoma. History of malignancy within the past 5 years except for specific cancers that are cured by surgical resection (e.g., skin cancer). Participants under evaluation for possible malignancy are not eligible. History of vasculitis or presence of symptoms and signs of potential vasculitis (e.g., vasculitic rash, skin ulceration, repeated blood detected in urine without identified cause) current or history of an autoimmune condition or history/presence of other diseases that may be associated with vasculitis condition (e.g., systemic lupus erythematosus, rheumatoid arthritis, relapsing polychondritis, mononeuritis multiplex). History of extrahepatic disorders possibly related to HBV immune conditions (e.g., nephrotic syndrome, any type of glomerulonephritis, polyarteritis nodosa, cryoglobulinemia, uncontrolled hypertension). History of alcohol or drug abuse/dependence. Currently taking, or took within 3 months of screening, any immunosuppressing drugs (e.g., prednisone), other than a short course of therapy (≤2 weeks) or topical/inhaled steroid use. Participants to whom immunosuppressive treatment, including therapeutic doses of steroids is contraindicated, should not be considered for enrolment in the study. Currently taking, or has taken within 12 months of Screening, any interferon containing therapy. Participants requiring anti coagulation therapies (e.g., warfarin, Factor Xa inhibitors) or anti-platelet agents (like clopidogrel or aspirin) unless treatment can safely be discontinued throughout duration of the study, by the discretion of the investigator. Occasional use is permitted. Prior treatment with any oligonucleotide or siRNA within 12 months prior to the first dosing day. Prior treatment with bepirovirsen.