Silence Continued Expansion of IP

Continued expansion of Intellectual Property - additional US patent application allowed for grant

30 May 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 a further step in the expansion of its chemical modification patent estate.

Earlier in May 2017, Silence announced that it had expanded and strengthened its above patent estate by filing additional divisional and continuation patent applications in Europe and the US respectively. The Company also announces that subsequently the US Patent Office issued a notice of allowance for US patent application 14/977,710. Silence has made the relevant payment of grant fees and normal practice is that the granted patent will now be issued by the US Patent and Trade Mark Office

The allowed claims of US patent application 14/977,710 provide Silence with further protection for its innovative chemical modification technology in the US. We believe these allowed claims are relevant to third party medicines in ongoing clinical trials for conditions including, but not exclusively limited to, Hypercholesterolemia, Haemophilia and Acute Hepatic Porphyrias.

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

"In allowing this additional patent application for grant, the US patent office has continued to uphold the validity of our expanding US patent estate. We continue to believe that several third party late-stage clinical RNAi candidates, including lipid nanoparticle and GalNAc based products, require licences under our patent portfolio, and have therefore written to one company to this effect. Silence is committed to defending and securing the appropriate value for our IP and is exploring alternative ways to leverage this asset. The first launch for these medicines is anticipated in 2018. We consider that potential licences under our patent estate could have a significant financial effect relative to the current market capitalisation of Silence."

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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.