Arrowhead receives approval to initiate Phase 2a clinical trial of ARC-520 for chronic HBV infection

Arrowhead Research Corporation (NASDAQ: ARWR), a biopharmaceutical company developing targeted RNAi therapeutics, today announced that it received regulatory approval to begin a Phase 2a clinical trial of ARC-520, its RNAi-based drug candidate for the treatment of chronic hepatitis B virus (HBV) infection. The Hong Kong Department of Health issued a Certificate for Clinical Trial, allowing the Company to proceed with its planned single-dose study of ARC-520 in two cohorts at two dose levels to be conducted at Queen Mary Hospital and Prince of Wales Hospital in Hong Kong. A site initiation was completed and patient screening will initiate shortly. The Company expects top line study results to be available in the third quarter of 2014.

The Phase 2a study is a multicenter, randomized, double-blind, placebo-controlled, dose-escalation study to determine the depth and duration of hepatitis B surface antigen (HBsAg) reduction after a single intravenous dose of ARC-520 in combination with entecavir in patients with chronic HBV infection. Single doses of ARC-520 will be evaluated at up to two ascending doses of 1.0 mg/kg and 2.0 mg/kg. At each of the two dose levels to be evaluated, a cohort of 8 patients will be enrolled with 6 being dosed with ARC-520 and 2 being dosed with placebo. This study will be conducted in adult male and female patients aged 16 to 65 years, with immune active chronic HBV infection, HBV e antigen (HBeAg) negativity, and ongoing entecavir therapy.

The primary objective of the study is to evaluate the depth and duration of HBsAg decline in response to a single dose of ARC-520 in combination with entecavir. Secondary objectives include evaluation of safety and tolerability and pharmacokinetic (PK) measures. Additional exploratory pharmacodynamics (PD) objectives include evaluation of the effect of ARC-520 on HBV DNA serum titers and antibodies to HBsAg (anti-HBs).