Further Strengthens US Patent Estate

Silence further strengthens US Patent Estate

11 September 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 that the US Patent and Trade Mark Office has issued a notice of allowance for US patent application 15/594,438. A further key US patent 9,758,784 is to be granted tomorrow to Silence.

Silence has made the relevant payment of grant fees for US patent application 15/594,438 and normal practice is that the granted patent will now be issued by the US Patent and Trade Mark Office.

As previously mentioned on 31 July 2017, the US Patent and Trade Mark Office issued a notice of allowance for US patent application 15/589,971, which will issue tomorrow as US patent 9,758,784.

The allowed claims of both patents when granted provide Silence with further protection for its innovative chemical modification technology in the US.

Silence believes these allowed claims are relevant to third party medicines in ongoing clinical trials.

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

"This notice of allowance and grant in the US provides further protection for our US patent estate. Combined with our other recently allowed US patent applications, we will have ten granted US patents, one US patent application, three granted European patents and four European patent applications encompassing our chemical modification technology. Our chemical modification patent portfolio also encompasses patents and patent applications in the following countries: Australia, Brazil, Canada, China, Israel, India, Japan, Korea, Mexico and South Africa. We continue to believe that several third party late-stage clinical RNAi candidates require licences under our patent portfolio and that such licences could have a material financial effect on 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.