Silence Therapeutics Announces Positive Outcome From Oral Hearing at the European Patent Office

LONDON, December 7, 2011 /PRNewswire/ --

Silence Therapeutics plc (AIM: SLN) ("Silence" or the "Company"), a leading RNA interference (RNAi) therapeutics company, announces a positive outcome from the oral hearing on 6 December 2011 at the European Patent Office (EPO) over opposition to Silence's granted European Patent EP 1 536 827 "Further use of protein kinase N beta".

The granted patent refers to the gene target PKN3, protein kinase N beta, targeted by Silence's lead program Atu027, which is currently in a Phase I clinical study. The Opposition division of the EPO decided to uphold the patent in amended form.

Claim one of the patent relates to the use of protein kinase N beta as a downstream target of the PI3 kinase pathway. Claim two relates to the use of protein kinase N beta as a downstream drug target of the PI3 kinase pathway in a screening process. Both of these claims are maintained as granted, and also the use claims where manufacture of a diagnostic agent is based on use of protein kinase N beta as such (or use of antibodies, spiegelmers, aptamers, ribozymes, antisense molecules and siRNA molecules directed against protein kinase N beta and the nucleic acid molecule coding for these, respectively).

In connection with the use claims where protein kinase N beta as such (or antibodies, spiegelmers, aptamers, ribozymes, antisense molecules and siRNA molecules directed against protein kinase N beta and the nucleic acid molecule coding therefore, respectively) are used for the manufacture of a medicament, the diseases for which such medicament is to be used are now restricted to metastatic cancers. This is the focus of Silence's currently ongoing Atu027 Phase I study with late-stage cancer patients.

Commenting on today's announcement, Thomas Christély, Chief Executive Officer of Silence, said: "We are very pleased with the outcome of this oral opposition hearing, which has upheld the key part of our claims in this granted patent. In addition to this granted patent on PKN3, our Atu027 clinical program is also protected by further granted patents and patent applications for the formulation with Silence's AtuPLEX™ delivery technology, the sequence of the siRNA molecules and the AtuRNAi chemistry used in the sequence. Our Atu027 trial continues as planned with two patients now recruited for cohort 10 out of 11 dose levels, and we are still on track to complete recruitment in early 2012 with results reported by mid-2012."

Notes for editors                  

About Silence Therapeutics plc (http://www.silence-therapeutics.com)

Silence Therapeutics plc (AIM: SLN) is a leading biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases. Silence offers one of the most comprehensive short interfering RNA (siRNA) therapeutic platforms available today based on a strong intellectual property portfolio and large clinical safety database. Silence's clinical siRNA product pipeline is one of the broadest in the industry. The Company possesses multiple proprietary siRNA delivery technology platforms including AtuPLEX™, DACC and DBTC. AtuPLEX enables the broad functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake. The DACC delivery system allows functional delivery of siRNA molecules selectively to the lung endothelium with a long duration of target mRNA and protein knock-down. The DBTC delivery system enables functional delivery of siRNA molecules selectively to liver cells including hepatocytes. Additionally, the Company has a platform of novel siRNA molecules based around its AtuRNAi chemical modification technology, which provides a number of advantages over conventional siRNA molecules. Silence's unique RNAi assets also include structural features for RNAi molecules and specific design rules for increased potency and reduced off-target effects of siRNA sequences.

The Company's lead internal drug candidate is Atu027, a liposomal formulation in clinical development for systemic cancer indications and one of the most clinically advanced RNAi therapeutic candidates in the area of oncology. Atu027 incorporates two of the Company's technologies, AtuRNAi and AtuPLEX^™. Silence is currently conducting an open-label, single-centre, dose-escalation Phase I study with Atu027 in patients with advanced solid tumors involving single, as well as repeated, intravenous administration. Encouraging interim safety and pharmacokinetic data were presented at the American Society of Clinical Oncology Annual Meeting in June 2011. The study is expected to be completed in the first half of 2012.

The Company's RNAi therapeutic platform has received key validation through multiple partnerships with pharmaceutical companies including Dainippon Sumitomo, Pfizer/Quark, and Novartis/Quark. Silence is actively pursuing the establishment of additional partnerships. Silence Therapeutics has operations in both Berlin and London.

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.

For further information, please contact:
       
Silence Therapeutics
Thomas Christély/Max Herrmann
+49-30-9489-2800/+44-20-7491-6520
[email protected]
[email protected]
                   
Singer Capital Markets
Shaun Dobson/Claes Spång
+44-20-32057500
[email protected]
[email protected]

M:Communications (Europe)
Peter Laing / Emma Thompson/ Claire Dickinson
+44-20-7920-2345 / +44-20-7920-2342
[email protected]

SOURCE Silence Therapeutics Plc