Arrowhead Induces 90% Reduction in Hepatitis B Antigens in Chimpanzee with Chronic Infection: Data Follow Previous Report of Reduction in Viral DNA
- Through 29 days after initial treatment, maximal knock down of HBV DNA, e-antigen, and s-antigen were approximately 95%, 90%, and 90%, respectively
- Results discussed today at an analyst event and webcast from 12:30 to 2:00 p.m. EDT
- Panel members for the event include Dr. Robert Gish, noted hepatologist and Arrowhead Clinical Advisory Board Chairman, and Joan Block, Executive Director and Co-founder of Hepatitis B Foundation
PASADENA, Calif. — March 25, 2013 — Arrowhead Research Corporation (NASDAQ: ARWR), a targeted therapeutics company, will host an analyst event today in New York City to discuss ARC-520, its RNAi-based candidate designed to treat chronic hepatitis B virus infection. The company will discuss the program and describe new preclinical data showing that a low dose of ARC-520 induced rapid and deep reductions in viral particles and key viral antigens in a chimpanzee chronically infected with hepatitis B virus. Arrowhead identified a well-tolerated dose of ARC-520 that lead to a 95% reduction in circulating viral DNA, and approximately 90% reductions in hepatitis e-antigen (HBeAg) and s-antigen (HBsAg), which are thought to be important in establishing a functional cure. These data support previous findings in rodent models and may be predictive of a therapeutic dose range to be identified in upcoming clinical trials expected to start in the middle of this year.
“This is the first time I have tested an siRNA therapy that was efficiently delivered to the liver and suppressed HBV infection including serum levels of HBsAg, a marker that is not suppressed effectively using current therapies,” said Dr. Robert Lanford of the Texas Biomedical Research Institute where the study was conducted. “This was a proof-of-concept study with a novel approach for curing HBV infection and this therapy provided highly promising results in a very short trial.”
The study was designed to test tolerability of a low dose of ARC-520 and its ability to reduce viral load and the key viral proteins, HBsAg and HBeAg, after intravenous administration in a chimpanzee with chronic hepatitis B infection. The animal being treated had exceptionally high titers of circulating HBV DNA and HBsAg that measured 1,000 to 10,000-fold higher than the average chronic hepatitis B patient. The HBV infection has been chronic for over thirty years and has persisted despite prior therapy with multiple anti-viral drugs and therapeutic vaccine exposures.
“Treating this animal represented a very difficult challenge,” said Dr. Chris Anzalone, President and CEO of Arrowhead. “It was the first large primate to be treated with ARC-520, and its viral and s-antigen loads were many orders of magnitude higher than what we expect to see in humans. Even with this high bar, we showed that a low dose was effective and extremely well tolerated. There is currently no way to reliably knock down key HBV antigens, thought to be critical to achieving a functional cure of the disease. Our data in multiple rodent models and now in a chimpanzee with chronic HBV infection suggest that ARC-520 may be able to provide this. We believe this is very important and positions us well for our planned clinical trials this year.”