Holding(s) in Company

25 Jul 2008 10:57

Silence Therapeutics plcHolding in Company

London 25 July 2008 - Silence Therapeutics plc (the "Company") announces that it received notification yesterday that, following an acquisition of ordinary shares on 21 July 2008, Credit Agricole Cheuvreux International Limited are now the beneficial owners of 3,669,133 ordinary shares of the Company, representing 3.06% of the Company's total voting rights.

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Enquiries:

For further information, please contact the following:

Silence Therapeutics plc Citigate Dewe Rogerson +44(0)20 7307 1620 +44(0)20 7638 9571 Iain Ross, Chairman & CEO David Dible Melvyn Davies, Finance Director Heather Keohane Nominated Advisers Nomura Code Securities Limited +44(0)20 7776 1200 Chris Collins Notes to Editors:

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

Silence Therapeutics plc (AIM: SLN) is a leading European RNAi focused biotechnology company. RNAi can selectively 'silence' genes linked to the onset of disease. RNAi is a Nobel Prize winning technology and one of the most promising areas of drug discovery and development today.

Silence Therapeutics has developed 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. In addition, the Company has developed a proprietary systemic delivery system, AtuPLEX. This system enables the functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake.

Silence's lead internal product, Atu027, is a proprietary AtuRNAi molecule in preclinical 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. Silence plans a regulatory filing in 2008 to commence clinical trials for Atu027.

In March 2008 Silence Therapeutics announced a collaboration with AstraZeneca focused on the development of a range of novel delivery approaches for siRNA molecules. Under the terms of the agreement both Silence Therapeutics and AstraZeneca will be allowed to commercialize the truly novel delivery systems that the two partners develop together.

In July 2007, Silence Therapeutics formed its first research and development collaboration with AstraZeneca to develop novel AtuRNAi therapeutics against five specific targets, including those in respiratory indications. This collaboration was the first industry validation of the potential application of Silence Therapeutics' proprietary AtuRNAi molecules and solidified the Company's leadership position in field of RNAi therapeutics.

The Company's AtuRNAi technology also has been sublicensed to Pfizer via Quark's license to them of the compound RTP-801i-14 for the treatment of age-related macular degeneration (AMD) and a number of other indications. This compound entered the clinic in early 2007. Silence Therapeutics also has licensed to Quark rights to the AtuRNAi structure for Quark's proprietary compound, AKIi-5, which is in a Phase I human clinical study for treatment of acute kidney injury.

Silence Therapeutics is based in London, UK, and Berlin, Germany, and is listed on AIM.

About RNAi

RNA interference (RNAi), is a Nobel Prize winning technology and one of the most exciting areas of drug discovery today. It represents a completely new approach to selectively 'silence' or inactivate disease relevant genes and as such it has the potential to create a new class of therapeutic products. RNAi could therefore offer a therapeutic approach to a broad range of diseases (cancer, infectious diseases, inherited diseases), many of which have been regarded as incurable and are not addressed by current therapeutics, therefore providing a large market opportunity.

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.