Completion of recruitment for phase 2a trial

16 July 2014

Silence Therapeutics plc

Completion of recruitment for Phase 2a clinical trial

Silence Therapeutics plc, AIM: SLN ('Silence' or 'the Company'), a leader in the discovery, development and delivery of novel RNA interference (RNAi) therapeutics for the treatment of serious diseases, has completed the recruitment of patients for its Phase 2a trial of Atu027 in pancreatic cancer.

Atu027 is Silence's leading short-interfering RNA (siRNA) therapy. It uses the Company's proprietary AtuPLEX® and AtuRNAi® technologies to broadly deliver siRNA to the endothelial cells of the vascular system, targeting the expression of the protein, PKN3, a key factor in cancer progression and metastasis.

Silence has reached its enrolment target of 24 patients for its study, to be completed at clinics across Germany. The primary objective is to evaluate the safety and pharmacokinetics of Atu027 when used in combination with standard chemotherapy treatment, Gemcitabine, in subjects with locally advanced or metastatic pancreatic adenocarcinoma. Follow up analysis is expected in mid-2015.

The preceding Phase 1 study of Atu027 was an open label, single centre, dose finding study in subjects with advanced solid cancer, and was completed in June 2013. Atu027 was found to be safe in patients with advanced solid tumours, with 41% of patients having stable disease for at least eight weeks.

Ali Mortazavi, CEO of Silence Therapeutics said:

"The completion of recruitment for this trial, on schedule, is a key milestone in the development of this programme and we are excited to follow the progress and the results of this novel treatment.

"Pancreatic cancer is the 12th most common cancer worldwide*. Around 338,000 new cases are diagnosed every year, most of them late stage. With a current five year survival rate of just 3-5%, there is clearly a high unmet medical need for drugs that can improve the outcome for patients with pancreatic tumours."

*Cancer Research UK, pancreatic cancer incidence and survival statistics, June 2014

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

Silence Therapeutics is a leading RNAi (RNA interference) therapeutics platform technology company which has proprietary delivery systems. Combined, the RNAi and delivery platforms enable the development of multiple products to multiple drug targets allowing the development of novel therapeutics for diseases with high unmet medical need.

Listed on London's AIM since 2006, Silence is one of only six quoted companies globally with well-validated RNA delivery technology. It has a robust IP estate, with three Phase II trials already completed (pending results).