US Allows Two Key Patents for Silence Therapeutics

LONDON, November 5, 2012 /PRNewswire/ --

Silence Therapeutics plc (AIM: SLN), a leading RNA interference (RNAi) therapeutics company, today announced that the US Patent and Trademark Office (USPTO) has issued a Notice of Allowance indicating that it will grant patents based on two applications: 12/986,389 and 13/230,084. These cover respectively interfering RNA molecules and lipid complexes used in drug delivery.

The claims allowed on interfering RNA molecules cover any double-stranded ribonucleic acid molecule where O-alkyl modified nucleotides are alternating with unmodified or differently modified nucleotides on both strands having a length of 17 to fewer than 30 ribonucleotides. This kind of modified double-stranded ribonucleic acid molecules form a key component of Silence's RNAi therapeutics. The patent will extend Silence's intellectual property related to double-stranded ribonucleic acid molecules to include molecules of 17 to fewer than 30 base pairs in length for use in methods for the treatment of disease. Importantly, the patent will protect any such double-stranded ribonucleic acid molecule across all therapy areas and cover double-stranded ribonucleic acid molecules irrespective of the specific nucleotide sequence used.

The claims allowed on lipid complexes, the proprietary lipid which is a key element of Silence's drug delivery technology Atufect, cover any composition irrespective of the class of compound to be delivered and irrespective of the disease to be treated.  The patent will both extend and widen Silence's intellectual property IP related to the field of drug delivery.

Commenting on the announcement Dr. Klaus Giese, Chief Scientific Officer of Silence, said: "These notifications from the USPTO further strengthens Silence's IP position in the arena of RNAi therapeutics and builds upon the already strong proprietary technology Silence offers its partners. The broad range of RNAi therapeutics in terms of their possible length of base pairs again distinguishes Silence from competitors which provide coverage for only very few lengths, if any.

"We welcome the decision of the USPTO on drug delivery as an appreciation of Silence's contribution. Drug delivery is key for the therapeutic use of functional nucleic acid molecules such as siRNA and miRNA. With this patent, Silence is becoming an even more attractive partner for companies interested in the delivery of a variety of classes of compounds with siRNA and miRNA being only two of them."

Notes for editors

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

Silence Therapeutics plc (AIM: SLN) is a leading biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases. Silence offers one of the most comprehensive short interfering RNA (siRNA) therapeutic platforms available today based on a strong intellectual property portfolio and large clinical safety database. Silence's clinical siRNA product pipeline is one of the broadest in the industry. The Company possesses multiple proprietary siRNA delivery technology platforms including AtuPLEX™, DACC and DBTC. AtuPLEX enables the broad functional delivery of siRNA molecules to targeted diseased tissues and cells, while increasing their bioavailability and intracellular uptake. The DACC delivery system allows functional delivery of siRNA molecules selectively to the lung endothelium with a long duration of target mRNA and protein knock-down. The DBTC delivery system enables functional delivery of siRNA molecules selectively to liver cells including hepatocytes. Additionally, the Company has a platform of novel siRNA molecules based around its AtuRNAi chemical modification technology, which provides a number of advantages over conventional siRNA molecules. Silence's unique RNAi assets also include structural features for RNAi molecules and specific design rules for increased potency and reduced off-target effects of siRNA sequences.

The Company's lead internal drug candidate is Atu027, a liposomal formulation in clinical development for systemic cancer indications and one of the most clinically advanced RNAi therapeutic candidates in the area of oncology. Atu027 incorporates two of the Company's technologies, AtuRNAi and AtuPLEX^™.

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

Silence Therapeutics
Ali Mortazavi, director of corporate strategy
+44(0)7768-694739
Tim Freeborn, finance director
+44(0)20-7491-6520
Email: [email protected]
 [email protected]

Singer Capital Markets
Shaun Dobson/Jenny Wyllie
+44(0)20-32057500
[email protected]
[email protected]

SOURCE Silence Therapeutics Plc