Silence Therapeutics Signs siRNA Delivery Collaboration With Top 10 Pharma Company

LONDON, September 27, 2011 /PRNewswire/ --

Silence Therapeutics plc (AIM: SLN) ("Silence"), a leading RNA interference (RNAi) therapeutics company, today announces that it has entered into an agreement with one of the world's leading global pharmaceutical companies to investigate the application of Silence's proprietary DACC delivery technology for intravenous delivery of short interfering RNA sequences ("siRNAs") to the pulmonary vascular endothelium.

Under the terms of the agreement, Silence's partner will provide Silence with specific siRNAs, which Silence will formulate with its DACC delivery system. Silence and its partner will undertake in vitro and in vivo studies of the DACC formulated siRNAs developed under the agreement and select lead candidates for further evaluation. Financial terms were not disclosed.

DACC is a novel lipid delivery system that includes Silence's proprietary lipid AtuFect and is used to embed siRNAs into a multiple lipid bi-layer structure. Whilst closely related to the AtuPLEXTM delivery system used in Atu027, Silence's lead oncology candidate in Phase I trials, DACC has significantly different properties on a physiochemical and pharmacological level. The DACC delivery system is incorporated in Atu111, Silence's preclinical development candidate for the treatment of acute lung injury, and enables functional, highly specific and efficient delivery of RNAi therapeutics to the pulmonary vascular endothelium. In preclinical models, the DACC delivery system has demonstrated highly focused delivery to lung tissue and sustained knockdown of the desired target gene expression in this particular cell type. Of note, the DACC delivery system has shown sustained protein knock-down of over three weeks.

Thomas Christély, Chief Executive Officer of Silence Therapeutics, said: "We are delighted to be collaborating with another of the world's largest pharmaceutical companies for the use of our delivery systems to deliver their selected siRNAs. As we have stated, Silence is now significantly increasing its resource in business development, and we are delighted to be announcing another partnership. We believe that Silence's proprietary DACC delivery system offers the potential to selectively deliver siRNAs and other oligonucleotides to pulmonary vascular endothelium, and we look forward to working closely with our partner on this project. Functional delivery into target cells is one of the greatest challenges facing most nucleic acid therapies and Silence remains committed to the development of its DACC and its other proprietary delivery systems, including AtuPLEXTM and DBTC, as it seeks to overcome these challenges."

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 AtuPLEXTM and DACC. 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. 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 AtuPLEXTM. 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 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 AstraZeneca, 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]

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