Silence Therapeutics Provides Research and Development Update IND approval received for SLN360 to start dose escalation studies Dosing initiated for SLN124, the first dose of a Silence GalNAc-siRNA given to humans 8 Sept

Silence Therapeutics Provides Research and Development Update

IND approval received for SLN360 to start dose escalation studies

Dosing initiated for SLN124, the first dose of a Silence GalNAc-siRNA given to humans

LONDON, Silence Therapeutics plc, AIM:SLN and Nasdaq: SLN ("Silence" or "the Company") a leader in the discovery, development and delivery of novel short interfering ribonucleic acid (siRNA) therapeutics for the treatment of diseases with significant unmet medical need, today provides a research and development update.

Complement Collaboration

Iain Ross, Executive Chairman of Silence Therapeutics, said: "In what has been a busy and successful year for Silence, we have continued to make significant progress with our R&D pipeline. We are delighted to announce today that we have received FDA approval of the IND application for our wholly owned lead product candidate, SLN360, which is designed to address a significant unmet medical need in cardiovascular disease for people born with high Lp(a) levels. We have also made strong progress with our wholly owned product candidate, SLN124, having now dosed the first healthy volunteer. This marks the first dose of a Silence GalNAc-siRNA given to humans and is the culmination of several years' work in developing this platform. This is truly an exciting time for Silence and we look forward to providing further updates as we move ahead."

About Silence Therapeutics

Silence Therapeutics is developing a new generation of medicines by harnessing the body's natural mechanism of RNA interference, or RNAi, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet medical need. Silence's proprietary technology can be used to engineer short interfering ribonucleic acids (siRNAs) that bind specifically to and silence, through the RNAi pathway, almost any gene in the human genome to which siRNA can be delivered. Silence's wholly owned product candidates include SLN360 designed to address the high and prevalent unmet medical need in reducing cardiovascular risk in people born with high levels of Lipoprotein(a) and SLN124 to address beta-thalassemia and myelodysplastic syndrome. Silence is also developing SLN500 in partnership with Mallinckrodt Pharmaceuticals to reduce the expression of the C3 protein for the treatment of complement pathway-mediated diseases. Silence maintains ongoing research and collaborations with AstraZeneca, Mallinckrodt Pharmaceuticals and Takeda. For more information, please visit: https://www.silence-therapeutics.com/

Forward-Looking Statements

Certain statements made in this announcement are forward-looking statements including with respect to the timing and outcome of the company's clinical trials, and its prospective achievement of milestones under collaboration agreements. These forward-looking statements are not historical facts but rather are based on the Company's current expectations, estimates, and projections about its industry; its beliefs; and assumptions. Words such as 'anticipates,' 'expects,' 'intends,' 'plans,' 'believes,' 'seeks,' 'estimates,' and similar expressions are intended to identify forward-looking statements. These statements are not guarantees of future performance and are subject to known and unknown risks, uncertainties, and other factors, some of which are beyond the Company's control, are difficult to predict, and could cause actual results to differ materially from those expressed or forecasted in the forward-looking statements. The Company cautions security holders and prospective security holders not to place undue reliance on these forward-looking statements, which reflect the view of the Company only as of the date of this announcement. The forward-looking statements made in this announcement relate only to events as of the date on which the statements are made. The Company will not undertake any obligation to release publicly any revisions or updates to these forward-looking statements to reflect events, circumstances, or unanticipated events occurring after the date of this announcement except as required by law or by any appropriate regulatory authority.