A Study of ARC-521 Injection in Normal Adult Volunteers and Patients With Chronic Hepatitis B (CHB)

Inclusion Criteria: * Male or female, 18 to 55 years of age inclusive (NHVs) or 18-65 years of age inclusive (CHBs), at the time of informed consent * Able to provide written informed consent prior to the performance of any study specific procedures * Body mass index (BMI) between 19.0 and 35.0 kg/m2, inclusive * A 12-lead ECG at Screening and pre-dose assessment that, in the opinion of the investigator, has no abnormalities that compromise participant's safety in this study * Must use 2 effective methods of contraception (double barrier contraception or hormonal contraceptive along with a barrier contraceptive (both male and female partners) * Have suitable venous access for blood sampling * No abnormal finding of clinical relevance at the Screening evaluation (NHVs only) * Have a diagnosis of HbeAg-negative chronic HBV infection (CHB patients only) * Treatment-naive or currently on entecavir/tenofovir for 6 months or longer Exclusion Criteria: * Pregnant or lactating * Acute signs of hepatitis/other infection at Screening or at baseline * Use within last 14 days or anticipated requirement for anticoagulants, systemic corticosteroids, immunomodulators, or immunosuppressants * Use of prescription medication within 14 days prior to study treatment that in the opinion of the PI or the Sponsor would interfere with study conduct. * Known diagnosis of non-alcoholic steatohepatitis \[NHVs only\] or familial hypercholesterolemia * Taking interferon alpha (INFalpha) within 6 months of screening \[CHBs only\] * History of poorly controlled autoimmune disease or history of autoimmune hepatitis * Human immunodeficiency virus (HIV) infection * Seropositive for HBV (NHVs only) or hepatitis C virus (HCV), and/or history of delta virus hepatitis * Hypertension defined as blood pressure \> 170/100 mmHg at screening \[NHVs only\] * A history of cardiac rhythm disturbances * Family history of congenital long QT syndrome, Brugada syndrome or unexplained sudden cardiac death * Symptomatic heart failure, unstable angina, myocardial infarction, severe cardiovascular disease within 6 months prior to study entry * History of malignancy within the last 5 years except for adequately treated basal cell carcinoma, squamous cell skin cancer, superficial bladder tumors, or in situ cervical cancer * History of major surgery within 3 months of Screening * Regular use of alcohol within one month prior to the Screening visit (more than fourteen units of alcohol per week) * Evidence of severe systemic acute inflammation, sepsis, or hemolysis \[NHVs only\] * Use within 3 months of illicit drugs (cocaine, phencyclidine \[PCP\], 3,4-methylenedioxymethamphetamine \[MDMA\], others) or positive test for drugs of abuse at screening. * History of allergy to bee venom or history of severe hypersensitivity reaction, such as anaphylaxis * Use of an investigational agent or device within 30 days prior to dosing or current participation in an investigational study * Clinically significant history of any alcoholic liver disease, cirrhosis, Wilson's disease, hemochromatosis, or alpha-1 antitrypsin deficiency, liver or kidney disease * Clinically significant history/presence of poorly controlled or decompensated neurological, endocrine, cardiovascular, pulmonary, hematological, immunologic, psychiatric, metabolic, or other uncontrolled systemic disease * Blood donation (500 mL) within 7 days prior to study treatment administration \[NHVs only\] * History of fever (\>38.0ºC/100.4ºF) within 2 weeks of Screening \[NHVs only\] * Any concomitant medical or psychiatric condition or social situation that impacts compliance or involves additional safety risk * History of coagulopathy (including deep vein thrombosis and pulmonary embolism) or stroke within 6 months of baseline, and/or concurrent anticoagulant medication(s) * Presence of cholangitis, cholecystitis, cholestasis, or duct obstruction