Arrowhead Wins Notice of Patent Allowance for New Protease Sensitive Masking Chemistry for DPC siRNA Delivery System

Arrowhead Research Corporation (NASDAQ: ARWR), a targeted therapeuticscompany, today announced that it has received a Notice of Allowance from theU.S. Patent and Trademark Office for U.S. Patent Application Number 13/336,028entitled, “In Vivo Polynucleotide Delivery Conjugates Having Enzyme SensitiveLinkages.” This new IP expands the Dynamic Polyconjugate (DPC) platform,broadly protecting Arrowhead's next generation DPC polymer maskingtechnology. Using this masking technology, DPCs can be engineered for longcirculation times and improved tissue-targeting characteristics. In addition,hepatocyte-targeted DPCs formulated using this new masking technology haveshown to be highly potent upon subcutaneous administration. The company haspreviously reported target gene knockdown of 99% in monkeys after a singlesubcutaneous injection of 1 mg/kg, with >80% knockdown for 3 months.Additional data will be reported at upcoming scientific conferences andthrough peer-reviewed publications.“This patent protects a new masking chemistry that broadens the reach ofDPC-enabled RNAi therapeutics. It enables efficient subcutaneous delivery ofsiRNA and opens up new therapeutic area targets including oncology,” said Dr.Chris Anzalone, President and CEO of Arrowhead. “Arrowhead scientists continueto discover innovative solutions for siRNA delivery and we look forward toproviding updates on how these technologies are being deployed to create newdrug candidates.”