Silence Therapeutics plc Receives Notice of Allowance for RNA Interference (RNAi) Patent Covering Novel Cancer Target  
2/8/2010 7:35:24 AM

LONDON and PALO ALTO, Calif., Feb. 8 /PRNewswire/ -- Silence Therapeutics plc (AIM: SLN) today announced that the United States Patent and Trademark Office (USPTO) has issued the company a notice of allowance on a patent application directed to methods of treatment using a high-value therapeutic target in the area of oncology. Known as PKN-3, the target is a protein kinase C-related molecule that is believed to play an important role in the growth of cancer cells, as well as metastasis formation. The allowed subject matter is directed to, among other things, methods of treating cancer with small interfering RNA (siRNA) or antisense molecules that target the PKN-3 messenger RNA (mRNA). The claims cover the siRNA molecule in Silence's lead clinical compound, Atu027, an RNAi therapeutic which targets PKN-3 for the treatment of advanced solid tumors.

Silence has built a strong and diverse intellectual property portfolio covering all essential areas of RNAi therapeutic development including multiple proprietary siRNA delivery technologies, potent siRNA sequences and key siRNA sequence and chemical modifications, as well as specific high-value disease targets.

Silence's lead internal product, Atu027, is a proprietary AtuRNAi(TM) molecule in clinical development for systemic cancer indications. Atu027 has successfully completed single and repeat dose toxicology and geno-toxicology studies, as well as a 28-day toxicology study using multiple dosing regimens. In June 2009 the company initiated an open-label, single-centre, dose-escalation Phase I study with Atu027 in patients with advanced solid (malignant) tumors involving single, as well as, repeated intravenous administration.

About Silence Therapeutics plc (

The company's strong and diverse intellectual property portfolio includes an exclusive license to the Zamore patent family from the University of Massachusetts, which covers broad structural features of siRNA design for more potent next generation siRNA sequences.

This press release includes forward-looking statements that are subject to risks, uncertainties and other factors. These risks and uncertainties could cause actual results to differ materially from those referred to in the forward-looking statements. All forward-looking statements are based on information currently available to Silence Therapeutics and Silence Therapeutics assumes no obligation to update any such forward-looking statements.

CONTACT: Phil Haworth of Silence Therapeutics, +1-650-855-1514,; or Richard Potts or Jonathan Senior,
both of Nomura Code Securities, 020 7776 1200; or media, Tim Brons,, or investors, Stephanie Diaz,, both of Vida Communication for Silence
Therapeutics, +1-415-675-7400

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