LONDON and PALO ALTO, California, February 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.

This action by the USPTO is the latest step in Silence's establishment of a proprietary and compelling RNAi therapeutic franchise which includes PKN-3 for the treatment of cancer. This development strengthens our dominant intellectual property position surrounding PKN-3, while specifically enhancing our global protection for Atu027, our Phase I candidate, said Philip Haworth, Ph.D., chief executive officer of Silence Therapeutics. At the same time, this milestone serves to supplement our already broad and diverse global RNAi intellectual property portfolio and enhances the significant proprietary position that this portfolio affords.

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.

About Atu027

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 (

Silence Therapeutics plc (AIM: SLN) is a leading global biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases. The company possesses multiple proprietary siRNA delivery technology platforms including AtuPLEX(TM), a system that enables the functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake. A second, complementary delivery technology known as PolyTran(TM) offers safe and effective systemic administration using a library of novel peptide-based biodegradable polycationic polymers. Additionally, the company has a platform of novel short interfering RNA (siRNA) molecules, AtuRNAi, which provide a number of advantages over conventional siRNA molecules, including increased stability against nuclease degradation. Silence's unique RNAi assets also include structural features for a next generation of RNAi molecules and additional proprietary siRNA sequences against more than 50 highly valued oncology and other disease targets.

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.

Silence Therapeutics is headquartered in London, UK, with research and development operations in Berlin and Palo Alto, CA.

Forward-Looking Statements

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.

SOURCE: Silence Therapeutics plc

CONTACT: Phil Haworth of Silence Therapeutics, +1-650-855-1514,; or Richard Potts or Jonathan Senior,both of Nomura Code Securities, +44-20-7776-1200; or media, Tim Brons,, or investors, Stephanie Diaz,, both of Vida Communication for SilenceTherapeutics, +1-415-675-7400