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Arrowhead Pharmaceuticals Provides Update on Heparc-2004 Study

PASADENA, Calif.–(BUSINESS WIRE)– Arrowhead Pharmaceuticals, Inc. (NASDAQ: ARWR) is providing an update on its Heparc-2004 clinical study of ARC-520, its therapeutic candidate under clinical investigation for the treatment of chronic hepatitis B virus (HBV) infection. Heparc-2004 is a multicenter, randomized, double-blind, placebo-controlled, multi-dose study of ARC-520, which is currently being performed in up to 12 patients in the United States under an Investigational New Drug (IND).

Arrowhead was notified today verbally by the United States Food & Drug Administration (FDA) of its decision to place a clinical hold on Heparc-2004. The study is on hold while the company provides responses to questions arising from a nonclinical toxicology study in non-human primates using EX1, the company’s liver-targeted, intravenously administered delivery vehicle.

The FDA did not indicate the clinical hold was based on any human findings. To date, EX1 has been administered over 800 times in more than 300 human study subjects and patients. Across this substantial clinical experience, only 3 serious adverse events (SAE) have been observed. Two of these were fevers, treated with acetaminophen, after which the patients continued on the study with no further complications. The other SAE was an instance of hepatic carcinoma in a patient with chronic HBV and cirrhosis, judged by the treating physician to be unrelated to the drug. A small minority (6%) of infusions in ARC-520 studies have been associated with infusion reactions, with 4 patients discontinuing ARC-520 treatment. In addition, across the ARC-520, ARC-521, and ARC-AAT clinical programs, laboratory values have not been deemed indicative of any drug-induced organ toxicity.

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