MiReven, Silence Therapeutics plc Ink Collaboration

London, UK, August 22, 2012 - Silence Therapeutics plc (AIM: SLN) ("Silence"), a leading RNA interference (RNAi) therapeutics company, announces that it has signed an agreement with MiReven Pty Ltd ("MiReven"), to assess the delivery potential of Silence's proprietary delivery systems with MiReven's novel microRNA-based therapeutics. MiReven, an Australian-based microRNA company, is commercialising discoveries from the Western Australian Institute for Medical Research (WAIMR) on the anti-cancer potential of miR-7.

Under the terms of the agreement, Silence will formulate a miR-7 mimetic (a potentially therapeutic mimic of the miR-7 molecule) with its proprietary AtuPLEX™, DACC and DBTC delivery systems in order to evaluate miR-7 in various cancer models. Silence will undertake in vitro and in vivo studies of the formulated miR-7. Silence is being paid an undisclosed fee for the collaboration.

AtuPLEX™, DACC and DBTC are proprietary RNAi delivery systems developed by Silence.

Silence's most advanced lipid delivery technology, AtuPLEX™, has demonstrated broad systemic delivery to the vascular endothelium. The AtuPLEX™ delivery system is used in Atu027, Silence's lead oncology candidate in Phase I trials. DACC, closely related to AtuPLEX™, is a novel lipid delivery system that enables functional, highly specific and efficient delivery of RNAi therapeutics to the pulmonary vascular endothelium. DBTC is a novel lipid-based formulation that functionally delivers siRNA to liver endothelial cells, hepatocytes and other liver cell types with high efficiency.

Klaus Giese, Chief Scientific Officer of Silence Therapeutics, said: "We are delighted to be collaborating with MiReven. This is the fourth collaboration that we have recently signed to explore the use of Silence's delivery technologies for microRNAs. Whilst we remain internally focused on the delivery of our siRNA therapies, we continue to broaden the potential value of our proprietary delivery systems by collaborating with partners. Functional delivery to target cells is widely recognized as one of the greatest challenges facing most nucleic acid therapies. Our three proprietary RNAi delivery systems, AtuPLEX™, DACC and DBTC, deliver effective doses of RNAi to key intracellular targets in vascular endothelium, lung and liver respectively, and provide our partners with a growing range of solutions to overcome their delivery challenges."

Stephen Thompson of MiReven Pty Ltd, said: "MiReven'sfounding scientists have developed a compelling body of preclinical data supporting the potential of miR-7 to suppress tumour growth, particularly in the many cancers known to be controlled by the EGF receptor signaling pathwayincluding glioblastoma. MiReven is currentlytesting drug-like versions of miR-7 in key models of human cancer."

For further information, please contact:

Silence Therapeutics MiReven Pty Ltd Ali Mortazavi/Jerry Randall Stephen Thompson Phone: +44 20 7491 6520 Phone: +61 3 9657 0700 Email: Email: sthompson@brandoncapital.com.au a.mortazavi@silence-therapeutics.com j.randall@silence-therapeutics.comSinger Capital Markets M:Communications Shaun Dobson/Claes Spång Mary-Jane Elliott / Sarah MacLeod / +44 20 32057500 Claire Dickinson shaun.dobson@singercm.com +44 20 7920 2342 claes.spang@singercm.com healthcare@mcomgroup.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 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 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.

About MiReven

MiReven Pty Ltd was formed in 2010 through an investment from the Medical Research Commercialisation Fund (MCRF). The company is commercialising the pioneering work of Prof Peter Leedman and Dr Keith Giles at the Western Australian Institute for Medical Research (WAIMR) on the anti-cancer potential of miR-7. WAIMR's published research shows that miR-7 can knock-out an essential growth receptor for cancer, known as the epidermal growth factor receptor (EGFR), with the additional potential to inhibit multiple EGFR signaling pathways that promote cancer development. EGFR is a major target for cancer therapy because it is often associated with disease progression, resistance to chemotherapy and radiation therapy. WAIMR is assisted in the commercialization of its intellectual property by the University of Western Australia, through its Office of Industry and Innovation.

About The Medical Research Commercialisation Fund (MRCF) (www.mrcf.com).

The $51 million Medical Research Commercialisation Fund (MRCF) Collaboration is an innovative investment collaboration established in 2007 and managed by Brandon Capital Partners (www.brandoncapital.com.au). The MRCF invests in early stage development and commercialisation opportunities emanating from its membership of 32 Australian medical research institutes and allied research hospitals, which includes the Western Australian Institute for Medical Research (WAIMR). The MRCF IIF, LP fund is supported by AustralianSuper, StatewideSuper and the Australian Government under its IIF program. The MRCF also acknowledges the support of the State Governments of Victoria, New South Wales, Western Australia and Queensland.

About MicroRNAs (miRNAs)

MicroRNAs have emerged as an important class of small RNAs encoded in the genome. They act to control the expression of sets of genes and entire pathways and are thus thought of as master regulators of gene expression. Recent studies have demonstrated that microRNAs are associated with many disease processes. Because they are single molecular entities that dictate the expression of fundamental regulatory pathways, microRNAs represent potential drug targets for controlling many biologic and disease processes.

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.

Back to news