“The main drawback of cholesterol-conjugated siRNAs is that their delivery is highly inefficient, and extraordinarily high doses would be needed to achieve even minimal amounts of target gene silencing,” said Bruce Given, MD, Arrowhead’s COO and Head of R&D. “Our strategy and the DPC platform enable much higher levels of gene silencing at dramatically lower doses of cholesterol-siRNA. Moreover, the ability to simply co-inject the cholesterol-siRNA with the DPC polymer without having to attach them together simplifies manufacturing and has facilitated our use of next generation polymers. This co-injection strategy and a next generation polymer are being used in our HBV clinical candidate, ARC-520.”About Arrowhead Research Corporation Arrowhead Research Corporation is a clinical stage targeted therapeutics company with development programs in oncology, obesity, and chronic hepatitis B virus infection. The company is leveraging its platform technologies to design and develop peptide-drug conjugates (PDCs) that specifically home to cell types of interest while sparing off-target tissues, create targeted drugs based on the gene silencing RNA interference (RNAi) mechanism, and work with partners to create improved versions of traditional small molecule drugs. For more information please visit http://www.arrowheadresearch.com, or follow us on Twitter @ArrowRes. To be added to the Company's email list to receive news directly, please send an email to firstname.lastname@example.org Safe Harbor Statement under the Private Securities Litigation Reform Act: This news release contains forward-looking statements within the meaning of the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. These statements are based upon our current expectations and speak only as of the date hereof. Our actual results may differ materially and adversely from those expressed in any forward-looking statements as a result of various factors and uncertainties, including our ability to finance our operations, the future success of our scientific studies, our ability to successfully develop drug candidates, the timing for starting and completing clinical trials, rapid technological change in our markets, and the enforcement of our intellectual property rights. Arrowhead Research Corporation's most recent Annual Report on Form 10-K and subsequent Quarterly Reports on Form 10-Q discuss some of the important risk factors that may affect our business, results of operations and financial condition. We assume no obligation to update or revise forward-looking statements to reflect new events or circumstances.