Notice of AGM and posting of Annual Report

3 November 2021

Oncimmune Holdings plc

("Oncimmune" or the "Company")

Notice of Annual General Meeting and posting of Annual Report

Oncimmune Holdings plc (AIM: ONC.L), the leading global immunodiagnostics group, today gives notice that its Annual General Meeting ("AGM") will be held at 10:00am GMT on 26 November 2021 at the offices of Pinsent Masons LLP, 30 Crown Place, Earl Street, London, EC2A 4ES.

The Company's Annual Report and Accounts for the year ended 31 May 2021 and the Notice of AGM have been sent to shareholders and can also be viewed on the "Investors" section of the Company's website at www.oncimmune.com.

In light of the on-going COVID-19 pandemic and the fact that UK Government restrictions and guidelines as to public gatherings and social distancing can be altered at short notice, the Board strongly urges all shareholders to register their votes in advance by appointing the Chairman of the meeting as their proxy and to provide their voting responses in advance of the AGM.

However, if shareholders nonetheless plan to attend the AGM in person, they are asked to email the Company at company.secretary@oncimmune.com by 10.00am GMT on 24 November 2021 to confirm that intention, giving details of their name and shareholder reference number. Oncimmune is asking shareholders to do this so that it can seek to put in place any appropriate measures to comply with the then current UK Government restrictions and guidelines (to the extent there are any) regarding public gatherings and social distancing. The health and safety of shareholders and colleagues is the Company's priority, and we are committed to supporting the UK Government's efforts in relation to the response to the COVID-19 pandemic.

To further facilitate engagement with investors, shareholders can submit questions to the Directors ahead of the AGM by email to agm2021@oncimmune.com. The Directors will endeavour to respond to appropriately raised questions in a timely manner.

For further information:

Oncimmune Holdings plc

Dr Adam M Hill, Chief Executive Officer

Matthew Hall, Chief Financial Officer

contact@oncimmune.co.uk

Singer Capital Markets (Nominated Adviser and Joint Broker)

Aubrey Powell, Harry Gooden, George Tzimas, James Fischer

+44 (0)20 7496 3000

WG Partners (Joint Broker)

David Wilson, Nigel Barnes, Nigel Birks

+44 (0)20 3705 9321

Media enquiries:

FTI Consulting

Ben Atwell, Michael Trace, Alex Davis

Oncimmune@fticonsulting.com

+44 (0)20 3727 1000

About Oncimmune

Oncimmune is a leading immunodiagnostics developer, primarily focused on the growing fields of immuno-oncology, autoimmune disease and infectious diseases. Oncimmune has a diversified and growing revenue base, both from its portfolio of diagnostic products to detect early-stage cancer and its contract discovery and development service business whose platform delivers actionable insights into therapies to the Company's pharmaceutical and biotech partners.

Our understanding of the immune system enables us to harness its sophisticated response to disease to detect cancer earlier and to support the development of better therapies. The key to improving cancer survival is early detection and better selection for therapy. As a company, we are driven by our passion to improve cancer survival and to give people extra time.

Oncimmune's ImmunoINSIGHTS platform enables life science organisations to optimise drug development and delivery, leading to more effectively targeted and safer treatments for patients. Oncimmune's immunodiagnostic technology, EarlyCDT, can detect and help identify cancer on average four years earlier than standard clinical diagnosis. Our lead diagnostic test, EarlyCDT Lung, targets a vast market estimated to grow to £3.8bn by 2024. With over 200,000 tests already performed for patients worldwide and its use being supported by peer reviewed data in over 12,000 patients, we are poised to become an integral component of future lung cancer detection programmes, globally.

Oncimmune is headquartered at its EarlyCDT product and R&D laboratory facility in Nottingham, UK and its ImmunoINSIGHTS pharma services commercial laboratory facility is based in Dortmund, Germany. The ImmunoINSIGHTS Commercial Team is based in the US and Europe.

For more information, visit www.oncimmune.com