SLN.L Regulatory News (SLN)

23 Jun 2009 07:00

First patient dosed in trial of Silence Therapeutics' Atu027

London - June 23, 2009 - Silence Therapeutics plc (AIM: SLN) ("Silence" or "the Company"), the leading European biopharmaceutical company focused on RNA interference (RNAi), announces that dosing has begun in a phase I study of Atu027, its lead drug candidate for the treatment of advanced solid tumours.

The trial is being conducted at the clinical study centre of the Cancer Hospital SanaFontis in Freiburg, Germany. Clinicians are conducting an open-label, dose-finding study to address the safety, tolerability and pharmacokinetics of Atu027. It is expected that the trial will take approximately 18 months to complete.

Iain Ross, chairman and chief executive of Silence Therapeutics said: "We are pleased that this important trial of our lead product, Atu027 for the treatment of patients with advanced solid tumours, is now under way. Silence believes that Atu027 could be a valuable option for patients who do not respond to standard therapy."

Atu027 specifically targets PKN3, a molecule involved in cancer growth and metastasis formation. Atu027 is Silence's most advanced clinical candidate for a systemically delivered short interfering RNA (siRNA) using the Company's proprietary AtuPLEX delivery technology.

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Enquiries:

For further information, please contact the following:

Silence Therapeutics plc Powerscourt 44 (0) 20 7491 6520 +44 (0) 20 7250 1446 Iain Ross, Chairman & CEO Paul Durman Kay Larsen Nominated Advisers Nomura Code Securities Limited +44(0)20 7776 1200 Richard Potts Notes to editorsAbout Atu027

Atu027 is Silence's lead internal product. It specifically targets PKN3, a molecule involved in cancer growth and metastasis formation. Silence's liposomal complex (siRNA-lipoplex) targets the vascular endothelial cell compartment delivering PKN3-siRNA into the cytoplasm of endothelial cells, where it acts catalytically on PKN3 mRNA via the gene silencing mechanism.

Silence submitted the Clinical Trial Application for Atu027 in December 2008 having successfully completed single and repeat dose toxicology and geno-toxicology studies, as well as a 28-day toxicology study using multiple dosing regimens.

About the trial

The trial will be conducted at the clinical study centre of the Cancer Hospital SanaFontis in Freiburg, Germany. The Cancer Hospital SanaFontis is an international centre for holistic cancer therapy and clinical cancer research. Both out- and in-patients of the hospital have the option to participate in studies that investigate innovative therapies, provided the patients can be expected to benefit from the treatment and there are no further therapy options open to them.

The trial will be an open-label , single-centre, dose-finding Phase I study with Atu027 in subjects with advanced solid tumours involving single as well as repeated intravenous administration. An open-label trial is a trial in which in which both the researchers and participants know which treatment is being administered.

The trial will address safety, tolerability and pharmacokinetics. Pharmacokinetics is the study of the way the body interacts with a particular drug, including the mechanisms of absorption and distribution, the rate at which a drug action begins and the duration of the effect, the chemical changes of the substance in the body and the effects and routes of excretion of the metabolites of the drug.

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

Silence Therapeutics plc (AIM: SLN) is a leading European RNAi-focused biotechnology company.

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.

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.

Following the granting of its patents in Europe, the USA and Australia, Silence Therapeutics is one of only two companies worldwide with a proprietary position on composition of matter for siRNA therapeutics.

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.

Silence Therapeutics has granted a licence to AstraZeneca to develop novel AtuRNAi therapeutics against five specific targets. 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 a phase II clinical study in July 2008. 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.

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.

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