Silence Therapeutics Post-Fundraising Update

London, June 1, 2011 - Silence Therapeutics plc (AIM: SLN) ("Silence", the "Group" or the "Company"), a leading global RNA interference (RNAi) therapeutics company, today provides a progress update following completion of its recently announced £5.9m fundraising.

Fundraising
On 16 May 2011, Silence successfully raised £5.9m (£5.5m net of expenses) through a placing and open offer. The fundraising was supported by both existing and new shareholders and puts the Group on a substantially improved financial footing. This will enable Silence to:
i) Complete the ongoing Phase I trial of Atu027 for treatment of advanced solid cancer (H2 2011)
ii) Initiate a Phase Ib trial of Atu027 in particular tumour types (mid-2012)
iii) File an investigational new drug application (IND) with the US Food and Drug Administration (FDA) for Atu134 for the treatment of solid tumours (H2 2012)
iv) Advance preclinical development of the Atu111 program for systemic delivery to the lung for the treatment of pulmonary disease

Atu027
Atu027, Silence‟s most advanced internal drug candidate, is a liposomal siRNA formulation targeting PKN3 for the treatment of advanced solid cancer that incorporates Silence‟s proprietary AtuPlex delivery technology. Atu027 has been shown to work by an anti-angiogenic process: inhibiting the growth of blood vessels, thereby inhibiting blood supply to the tumour.

Atu027 is currently the subject of a Phase I clinical trial in cancer patients with solid tumours. Interim results from the trial, which demonstrate disease stabilisation and potential anti-tumour activity, are encouraging and, to date, Atu027 has been shown to be safe and well tolerated. Silence will present updated interim results from the ongoing Phase I study at the American Society of Clinical Oncology („ASCO‟) on 6 June 2011. Silence expects to complete the Phase I trial in H2 2011 and announce results before year-end. A Phase Ib/IIa trial is expected to commence in mid-2012.

Silence plans to partner Atu027 during the course of 2012.

Atu134
Atu134 is Silence‟s second potential cancer therapy. Similarly to Atu027, Atu134 is also an anti-angiogenic drug that incorporates the AtuPlex technology. Atu134 specifically targets CD31, a target that has proved intractable to small molecule and antibody approaches to date. Silence has now completed studies in multiple preclinical cancer models which demonstrated that Atu134 has a profound impact on slowing the progression of solid tumours. Production of Good Manufacturing Practice materials for final preclinical toxicology studies is due to start soon. Toxicology studies are planned for H1 2012 and Silence plans to file an IND application to the FDA to initiate a Phase I trial of Atu134 in H2 2012.

Atu111
Atu111, for the treatment of acute lung injury, is the Company‟s most advanced drug development candidate outside oncology. Atu111 combines Silence‟s recently developed DACC drug delivery system with AtuRNAi. The target for this RNAi therapeutic is undisclosed. However, preclinical models using the DACC delivery system have shown sustained knockdown of up to three weeks in the lung endothelium.

Silence believes Atu111 is an attractive opportunity for potential pharmaceutical partners.

Partnerships and collaborations
Silence continues to work closely with its partners and looks forward to the initiation of a Phase IIb trial of PF-„655, licensed to Quark Pharmaceuticals and Pfizer Inc., in diabetic macular oedema expected to commence in H2 2011. In addition, Silence expects Quark Pharmaceuticals and Pfizer Inc. to report results from the Phase II trial of PF-„655 for the treatment for age-related macular degeneration later in 2011.

Quark Pharmaceuticals is also developing QPI-1002 for the treatment of delayed graft function and acute kidney injury in partnership with Novartis. In September 2010, Quark initiated a Phase II trial of QPI-1002 for the treatment of delayed graft function and plans to initiate a second Phase II trial of QPI-1002 in acute kidney injury during the course of 2011.

Silence‟s collaborations with AstraZeneca and Dainippon Sumitomo are ongoing.

Restructuring
In conjunction with the recent fundraising, Silence announced plans to close its US operations. Actions have now been implemented to close the US facility in Q3 2011. As part of the reorganisation, Phil Haworth will step down as CEO once a successor is identified, as previously announced. Recruitment of a new CEO is ongoing, and Silence anticipates an orderly transition of management.

Annual General Meeting
Silence‟s Annual General Meeting will be held on Monday 13 June 2011. The meeting will be held at Silence‟s offices at the Royal Institute of Great Britain, 21 Albemarle Street, London W1S 4BS, commencing at 11.00am BST. A corporate presentation will be made to attendees after the meeting and will be available to download from www.silence-therapeutics.com/corporatepresentation.

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