SLN.L Regulatory News (SLN)

6 Jan 2012 07:00

Research and Development Collaboration Update

London, January 6, 2012 - Silence Therapeutics plc (AIM: SLN) ("Silence" or the "Company"), a leading RNA interference (RNAi) therapeutics company, announces the successful completion of its research work under the Research Collaboration and Delivery Collaboration with its partner AstraZeneca and its biologics arm, MedImmune. The first collaboration between Silence and AstraZeneca was initiated in 2007 and was extended in 2010 and includes five research programs on novel small interfering RNA (siRNA) therapeutic molecules for selected targets. The second collaboration, focusing on the development of novel approaches for the delivery of siRNA molecules, was established in 2008 and was also extended in 2010.

Under the first collaboration, Silence and AstraZeneca successfully identified, optimised and formulated novel siRNA molecules for selected targets and executed certain studies for five research programs. Three of these programs have been declared as "Accepted Programs" by AstraZeneca and can now be advanced into pre-clinical development. AstraZeneca retains the global development and commercial rights to these Accepted Programs. Silence will retain all rights with respect to the two research programs which did not become Accepted Programs. However, these two programs remain subject to a two-year option with a first right of refusal in favour of AstraZeneca. In addition, Silence acknowledges and agrees that AstraZeneca may continue to work on these two programs solely for its own internal research purposes.

The second collaboration led to the development by Silence of a novel delivery system for siRNA molecules, the DACC delivery system. Full rights to this system have been retained by Silence and complement the Company's unique AtuPLEXâ„¢ and DBTC RNAi delivery systems. The DACC delivery system allows selective functional delivery of siRNA molecules to the lung endothelium with a long duration of target mRNA and protein knock-down, compared to AtuPLEXâ„¢ which is used for broad delivery to the vasculature of several organs and DBTC which enables functional delivery of siRNA molecules selectively to liver cells including hepatocytes.

Commenting on today's announcement, Thomas Christ©ly, Chief Executive Officer of Silence, said: "We are pleased by the progress that we have made in both collaborations. In particular the delivery collaboration has enabled Silence to make significant progress in developing a new technology that delivers RNAi to target cells. The development of the lung focused RNAi delivery system DACC is an important outcome of the delivery collaboration. The DACC delivery technology is proprietary to Silence and can be applied to the other projects that we are pursuing by ourselves and with partners."

David Blakey, Chief Scientist Oncology iMed and Chair of Oligonucleotide Strategy Team, AstraZeneca, commented: "AstraZeneca and MedImmune remain committed to the development of new technologies that have the potential to create novel therapeutics. The collaboration with Silence Therapeutics has been excellent and AstraZeneca and MedImmune will continue to evaluate the novel siRNA molecules and the delivery technologies discovered under the collaboration as part of its overall strategy to explore this important therapeutic approach."

Ends

For further information, please contact:

Silence Therapeutics M:Communications Thomas Christ©ly/Max Herrmann Mary-Jane Elliott / Emma Thompson/ Claire Dickinson

+49 30 9489 2800/+44 20 7491 6520 +44 20 7920 2345 / +44 20 7920 2342 t.christely@silence-therapeutics.com silencetherapeutics@mcomgroup.com m.herrmann@silence-therapeutics.com

Singer Capital Markets Shaun Dobson/Claes Sp¥ng +44 20 32057500 shaun.dobson@singercm.com claes.spang@singercm.com Notes for editors

About Silence Therapeutics plc (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 AtuPLEXâ„¢, 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 AtuPLEXâ„¢. 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.