SLN.L Regulatory News (SLN)

FOR IMMEDIATE RELEASE

Termination of Offer Period

London, February 7, 2011 - Further to the announcement dated 7 September 2010, made in response to share price movement, Silence Therapeutics plc (AIM: SLN) ("Silence" or the "Company") confirms it is no longer in discussions which may lead to an offer for the Company. The Board is not aware of any parties with whom it has had discussions that are considering making an offer for the Company at this time. As such, the Company is no longer in an offer period for the purposes of the City Code on Takeovers and Mergers.

The Board of Silence received a number of indicative proposals but it is the view of the Board that none of these were sufficiently compelling to pursue further in the context of the continued success of the Company. The Board has therefore terminated these discussions to allow management to focus all of its efforts on the ongoing business for the purpose of creating long-term shareholder value.

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Notes for editors

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

Silence Therapeutics plc (AIM: SLN) is a leading global biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases. The company possesses multiple proprietary short interfering RNA (siRNA) delivery technology platforms including AtuPLEX™, a system that enables the functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake. A second, complementary delivery technology known as PolyTran™ uses a library of novel peptide-based biodegradable polycationic polymers for systemic siRNA administration. Additionally, the company has a platform of novel siRNA molecules, AtuRNAi, which provide a number of advantages over conventional siRNA molecules, including increased stability against nuclease degradation. Silence's unique RNAi assets also include structural features for a next generation of RNAi molecules and additional proprietary siRNA sequences against more than 50 highly valued oncology and other disease targets.

The company's strong and diverse intellectual property portfolio includes exclusive licenses from the University of Massachusetts Medical School on three patent families associated with the "Zamore Design Rules," which cover broad structural features of siRNA design for more potent next generation siRNA sequences.

The Company's RNAi therapeutic platform has received key validation through multiple partnerships with pharmaceutical companies including AstraZeneca, Dainippon Sumitomo, Pfizer, and Quark. Silence is actively pursuing the establishment of additional partnerships.

Silence Therapeutics is headquartered in London, UK, with research and development activities in Berlin and operations in Redwood City, CA.

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.

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