Silence Therapeutics Announces SLN360 Phase 1 Data Accepted for Late-Breaking Presentation at the American College of Cardiology (ACC) Annual Scientific Session and Expo

Data to be presented by Professor of Cardiovascular Medicine at the Cleveland Clinic, Steven Nissen, MD, on Sunday April 3, 2022

Silence on-track to report topline data from the SLN360 phase 1 single-ascending dose study this quarter

LONDON--(BUSINESS WIRE)-- Silence Therapeutics plc, 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 announced the acceptance of a late-breaking clinical abstract on the ongoing SLN360 phase 1 single-ascending dose study in healthy volunteers with high levels of lipoprotein(a) at the American College of Cardiology (ACC) Annual Scientific Session & Expo being held in Washington, DC, April 2-4, 2022.

Silence remains on-track to report topline data from the SLN360 phase 1 study via press release this quarter.

Detailed results from the SLN360 phase 1 single-ascending dose study (“APOLLO Trial”) will be presented by principal investigator, Steven E. Nissen, MD, at the ACC meeting on April 3, 2022.

Session Title: Joint American College of Cardiology/Journal of the American Medical Association Late- Breaking Clinical Trials

Date: Sunday, April 3, 2022; 8:00 a.m. – 9:15 a.m. ET

Abstract Title: APOLLO Trial: Magnitude and Duration of Effects of a Short-interfering RNA Targeting Lipoprotein(a): A Placebo-controlled Double-blind Dose-ranging Trial

Presenter: Steven E. Nissen, MD, Principal Investigator for the APOLLO Trial, Cleveland Clinic, Cleveland, OH, USA

For more information on the upcoming ACC meeting and to view the list of late-breaking clinical trial abstracts, please visit Late-Breakers (acc.org).

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 need. Silence's proprietary mRNAi GOLD™ platform can be used to create siRNAs (short interfering RNAs) that precisely target and silence disease-associated genes in the liver, which represents a substantial opportunity. 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 designed to address rare hematological diseases. Silence also maintains ongoing research and development collaborations with AstraZeneca, Mallinckrodt Pharmaceuticals, and Hansoh Pharma, among others. For more information, please visit https://www.silence-therapeutics.com/.

Forward-Looking Statements

Certain statements made in this announcement are forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and other securities laws, including with respect to the Company’s clinical and commercial prospects and the anticipated timing of data reports from the Company’s clinical trials. 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, including those risks identified in the Company’s most recent Admission Document and its amended Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission on April 29, 2021. 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.

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Enquiries:

Silence Therapeutics plc

Gem Hopkins, Head of IR and Corporate Communications

ir@silence-therapeutics.com

Tel: +1 (646) 637-3208

US Media Relations

MKC Strategies

Mary Conway

mconway@mkcstrategies.com

Tel: +1 (516) 606-6545

European Media Relations

Consilium Strategic Communications

Mary-Jane Elliott/ Angela Gray / Chris Welsh

silencetherapeutics@consilium-comms.com

Tel: +44 (0) 20 3709 5700

Source: Silence Therapeutics plc