Update on litigation matters

Update on litigation matters

20 November 2017

Silence Therapeutics plc, AIM:SLN ("Silence" or "the Company") a leader in the discovery, delivery, and development of novel RNA therapeutics for the treatment of serious diseases with unmet medical need, announces an update on litigation matters. Previously, Alnylam UK Limited and The Medicines Company UK Limited sued to revoke the relevant Silence European patent EP 2 258 847B in the UK, and also included claims for declarations of non-infringement of EP 2 258 847B by certain Alnylam products.

Silence has now served its Defence in the actions initiated by Alnylam and The Medicines Company and has counterclaimed for threatened infringement of the Silence European patent EP 2 258 847B by these companies. If successful, products including patisiran, fitusiran, givosiran and inclisiran will be found to infringe EP 2 258 847B.

Further, Silence notes that Alnylam and The Medicines Company are yet to serve their respective Defences in relation to the earlier served action brought by Silence for a declaration as to its entitlement to claim SPC protection on products containing the above-named active substances.

Silence continues to regard these actions from all parties as simply "normal course of business" at the commencement of litigation, and continues to believe that certain Alnylam products require a licence under the Silence patent estate.

Ali Mortazavi, Chief Executive Officer of Silence Therapeutics, commented:

"We continue to believe that our fundamental chemical modification technology is core foundational innovation for today's RNAi sector, and that therefore those companies using such modification technology within the scope of our Intellectual Property (IP) will require a licence."

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About Silence Therapeutics plc

Silence Therapeutics develops a new generation of medicines by harnessing the body's natural mechanism of RNA interference, or RNAi, within its cells. Our proprietary technology can selectively inhibit any gene in the genome, specifically silencing the production of disease-causing proteins. Using our enabling delivery systems, we have achieved an additional level of specificity by delivering our therapeutic RNA molecules exclusively to target cells. Silence's proprietary RNA chemistries and delivery systems are designed to improve the stability of our molecules and enhance effective delivery to target cells, providing a powerful modular technology well suited to tackle life-threatening diseases.