Silence Therapeutics Receives Allowance for US Patent

LONDON - Silence Therapeutics plc, a leading European RNAi focused biotechnology company, announced in a Thursday press release that the United States Patent and Trademark Office has allowed the Company‘s core RNAi patent application.

The Patent Office issued a ‘Notice of Allowance’ for patent application 10/633,630, “Interfering RNA Molecules,” which covers stabilized, small interfering RNA (siRNA) molecules with defined positional modifications. The claims cover siRNA molecules that are “blunt ended,” as well as molecules with one or more “overhangs” and specifically cover Silence Therapeutics’ proprietary siRNA molecules, known as “AtuRNAi”.

The company also announced today it has received a Notice of Acceptance from the Australian Patent Office for patent application No. 2003260370 entitled “Further novel forms of interfering RNA molecules.”  The European equivalent of the US and Australian patent applications was granted by the European Patent Office in January 2007.

Iain Ross, chairman & CEO of Silence Therapeutics, said “This is a major milestone for Silence, our partners and investors.  This patent allowance protects our AtuRNAi technology and our proprietary siRNA molecules in the United States, the largest pharmaceutical market in the world.  Silence already has a strong, proprietary position in the RNAi space and this allowance builds further on our global patent portfolio. With the US patent allowance, we are now significantly better positioned to achieve our goal of becoming one of the leading companies in the field of RNAi therapeutics and delivery.”

Silence considers its AtuRNAi to be best-in-class siRNA molecules based on important advantages over conventional siRNA molecules, including increased stability against nuclease degradation and an increased serum half-life, while retaining therapeutic activity.  AtuRNAi molecules form the basis of Silence’s therapeutic research and development collaboration with AstraZeneca, as well as the Company’s license and collaboration agreements with Quark Pharmaceuticals Inc. In addition, Silence is developing an internal, proprietary pipeline of systemically delivered AtuRNAi molecules that are initially focused on oncology indications.

Silence’s Intellectual Property portfolio includes patents and patent applications covering essential chemical modification to stabilize siRNA molecules in vitro and in vivo, as well as systemic siRNA delivery systems. These include AtuPLEX, Silence’s proprietary systemic delivery system that enables the functional delivery of novel siRNA therapeutic molecules to targeted tissues and cells.