Synairgen plc

('Synairgen' or the 'Company')

Appointment of Joseph Colliver as New Chief Financial Officer

Southampton, UK - 11 October 2023: Synairgen plc (LSE: SNG), the respiratory company developing SNG001, an investigational formulation for inhalation containing the immunomodulatory broad-spectrum antiviral protein interferon beta, today announces that Joseph Colliver has been appointed Chief Financial Officer (CFO) and Executive Director with effect from Monday 6 November 2023. In conjunction with this appointment, and following nearly 20 years of loyal service and an orderly handover, John Ward will step down from the role of CFO and Executive Director on Friday 3 November.

Joseph Colliver has significant financial leadership experience, including most recently as CFO and non-executive director of several listed life sciences companies. He has previously held CFO and senior commercial roles within the Kantar division of WPP PLC. He also has many years of experience as a consultant and in various Board roles, with a deep understanding of the strategy, governance and regulatory requirements of biotechnology companies.

Richard Marsden, CEO of Synairgen, said: "Joseph's many years of listed company experience, including in the healthcare sector, will stand us in good stead as we progress towards the clinic with our SNG001 strategy. I'd like to thank John for his steadfast commitment, loyalty and support to both me and the Board over many years. We wish him the very best for the future."

Joseph Colliver, newly appointed CFO of Synairgen, commented: "This is a pivotal time for the Company, as it works towards the next phase of clinical trials with SNG001. I look forward to working closely with Richard and the team in the coming months and years."

John Ward, outgoing CFO of Synairgen, commented: "It has been a pleasure to work with the Synairgen team for these many years, driven by the shared vision to develop treatments for severe viral lung infections. However, it's the right time to pass on the baton, and I look forward to following the Company's next steps and wish the team every success with SNG001 in the future."

Information required under Rule 17 and Schedule Two, paragraph (g) of the AIM Rules for Companies ("AIM Rules")

There is no further information to be disclosed in relation to the appointment pursuant to Rule 17 and Schedule Two, paragraph (g) of the AIM Rules.

For further enquiries, please contact:

Synairgen plc

Media@synairgen.com

Tel: + 44 (0) 23 8051 2800

Cavendish Capital Markets Limited (NOMAD and Joint Broker)

Geoff Nash, Charlie Beeson (Corporate Finance)

Sunila de Silva (ECM)

Tel: + 44 (0) 20 7220 0500

Numis Securities Limited (Joint Broker)

Freddie Barnfield, Duncan Monteith, Euan Brown

Tel: + 44 (0) 20 7260 1000

ICR Consilium (Financial Media and Investor Relations)

Mary-Jane Elliott, Namrata Taak, Lucy Featherstone

Synairgen@consilium-comms.com

Tel: +44 (0) 20 3709 5700

Notes for Editors

Synairgen is a UK-based respiratory company focused on drug discovery and the development of SNG001 (inhaled interferon beta) as potentially the first host-targeted, broad-spectrum antiviral treatment delivered directly into the lungs for severe viral lung infections.

Millions of people globally are hospitalised every year due to viral lung infections and there are currently no approved antiviral therapies for the majority of these patients. Synairgen is developing SNG001 to address this need.

Synairgen is quoted on AIM (LSE: SNG). For more information about Synairgen, please see www.synairgen.com.