Conditions: Hepatitis B
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 32
Healthy volunteers: no

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

Detailed description:
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 HBeAg positive 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 90 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.

Arms:
arm 1: Placebo (low dose comparator) once every 4 weeks for 4 doses, plus entecavir (0.5 or 1.0 mg/day) or tenofovir (300 mg/day) arm 2: Placebo (high dose comparator) once every 4 weeks for 4 doses, plus entecavir (0.5 or 1.0 mg/day) or tenofovir (300 mg/day) arm 3: Low dose (1.0 mg/kg) ARC-520 once every 4 weeks for 4 doses, plus entecavir (0.5 or 1.0 mg/day) or tenofovir (300 mg/day) arm 4: High dose (2.0 mg/kg) ARC-520 once every 4 weeks for 4 doses, plus entecavir (0.5 or 1.0 mg/day) or tenofovir (300 mg/day)

Interventions: intervention 1: ARC-520 intervention 2: Placebo intervention 3: entecavir intervention 4: antihistamine intervention 5: tenofovir
Intervention descriptions: intervention 1: None intervention 2: None intervention 3: All participants will take entecavir or tenofovir throughout the study. Participants will be instructed to take their medication daily. intervention 4: All participants will be pretreated with an oral antihistamine. The antihistamine used should in general be an H1\>H2 receptor blocker and would include diphenhydramine 50 mg, cetirizine 10 mg, chlorpheniramine 8 mg or hydroxyzine 50 mg. The Investigator is free to choose any of these antihistamines available locally and consistent with their country's Marketing Authorisation. intervention 5: All participants will take entecavir or tenofovir throughout the study. Participants will be instructed to take their medication daily.

Protocol document: