A Multi-dose Study of ARC-520 in Patients With Hepatitis B 'e' Antigen (HBeAg) Negative, Chronic Hepatitis B Virus (HBV) Infection

Patients with chronic HBV infection will receive either ARC-520 or placebo in combination with entecavir or tenofovir, and be evaluated for safety and efficacy.

This is a multicenter, randomized, double-blind, placebo-controlled, multi-dose study of ARC-520 in combination with entecavir or tenofovir administered to patients with Hepatitis B 'e' Antigen (HBeAg) negative and immune active chronic HBV infection. Eligible patients who have signed an Ethics Committee - approved informed consent, will be enrolled and will receive ARC-520 or placebo in combination with entecavir or tenofovir. The study will enroll up to a total of 60 eligible chronic HBV infected patients. Patients will undergo the following evaluations at regular intervals during the study: medical history, physical examinations, vital sign measurements (blood pressure, heart rate, respiratory rate and temperature), weight, adverse events assessment (AEs), 12-lead electrocardiograms (ECGs), liver fibrosis testing, concomitant medication assessment, blood sample collection for hematology, coagulation,chemistry, lactate, Pharmacokinetic (PK) measures (in a subset of patients), exploratory Pharmacodynamic (PD) measures, urinalysis, HBV serology, Follicle Stimulating Hormone (FSH) testing (post-menopausal females) and pregnancy testing for females of childbearing potential. Clinically significant changes including AEs will be followed until resolution, until the condition stabilizes, until the event is otherwise explained, or until the patient is lost to follow-up. For each patient, the duration of the study is approximately 33 weeks from screening to the Day 169 follow-up visit. For patients enrolling into a planned extension study, the total duration of this study is approximately 25 weeks from screening to Day 113 end of study visit.

Eligibility Criteria:
Inclusion Criteria:

* Male or female, 18 to 75 years of age
* Written informed consent
* No clinically significant abnormalities at screening/pre-dose 12-lead ECG assessment
* No new abnormal finding of clinical relevance at the screening evaluation.
* Diagnosis of HBeAg negative, immune active, chronic HBV infection
* \> 2 months of continuous treatment with daily, oral entecavir or tenofovir
* Willingness to continue taking entecavir or tenofovir throughout the study.
* Must use 2 effective methods of contraception (double barrier contraception or hormonal contraceptive along with a barrier contraceptive) (both male and female partners)

Exclusion Criteria:

* Pregnant or lactating
* Acute signs of hepatitis/other infection within 4 weeks of screening
* Antiviral therapy other than entecavir or tenofovir within 3 months of screening
* Prior treatment with interferon in the last 3 years.
* Use within the last 6 months or anticipated requirement for anticoagulants, corticosteroids, immunomodulators, or immunosuppressants.
* Use of prescription medication within 14 days prior to treatment administration except: topical products without systemic absorption, statins (except rosuvastatin), hypertension medications, or hormonal contraceptives.
* Depot injection or implant of any drug within 3 months prior to treatment administration, except injectable/implantable birth control.
* Diagnosis of diabetes mellitus.
* History of autoimmune disease especially autoimmune hepatitis.
* Human immunodeficiency virus (HIV) infection.
* Sero-positive for Hepatitis C Virus (HCV), and/or a history of delta virus hepatitis.
* Hypertension defined as blood pressure \> 150/100 mmHg
* History of cardiac rhythm disturbances
* Family history or 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 except for adequately treated basal cell carcinoma, squamous cell skin cancer, superficial bladder tumors, or in situ cervical cancer.
* Has had a major surgery within 3 months of screening.
* History of alcohol and/or drug abuse \< 12 months from screening.
* Regular uses of alcohol within 6 months prior to screening (ie, more than 14 units of alcohol per week).
* Evidence of severe systemic acute inflammation, sepsis, or hemolysis.
* Diagnosed with a significant psychiatric disorder.
* Use of recreational drugs, such as marijuana, within 3 months prior to screening
* Use of drugs such as cocaine, phencyclidine (PCP), and methamphetamines, within 1 year prior to screening.
* History of allergy to bee sting.
* Use of investigational agents or devices within 30 days prior to planned study dosing or current participation in an investigational study.
* Clinically significant history or presence of any gastrointestinal pathology, unresolved gastrointestinal symptoms, liver or kidney disease.
* Presence of cholangitis, cholecystitis, cholestasis, or duct obstruction.
* Clinically significant history or presence of poorly controlled/uncontrolled systemic disease.
* History of fever within 2 weeks of screening.
* Immunized with a live attenuated vaccine within 7 days prior to dosing or planned vaccination (excluding flu vaccine by injection).
* Presence of any medical or psychiatric condition or social situation that impacts compliance or results in additional safety risk.
* Participated in excessive exercise/physical activity within 7 days of screening or planned during the trial.
* History of coagulopathy/stroke within past 6 months, and/or concurrent anticoagulant medication(s).