Annual results 2021

2 November 2021

Oncimmune Holdings plc

("Oncimmune", the "Company" and, together with its subsidiaries, the "Group")

Full year results and progress update

FY2021 revenues of £3.7 million (over 6x increase on FY2020)

Continued delivery against three-year strategy, with FY2022 growth expected to continue to be driven

by ImmunoINSIGHTS services business

Oncimmune Holdings plc (AIM: ONC.L), the leading global immunodiagnostics group, today announces its audited results for the year ended 31 May 2021 ("FY2021") and provides an update on recent progress and the outlook for the current financial year ("FY2022").

Operational and commercial highlights:

ImmunoINSIGHTS

• Continued to strengthen strategic relationships with Roche and Genentech as well as with other global pharmaceutical companies
• Following the successful deployment of UK Government funding for the development of an infectious diseases research tool for use in COVID-19, the period saw the launch of an infectious diseases panel resulting in contracts with Roche and multiple contracts with Cedars-Sinai Medical Center, Los Angeles
• Agreement signed with a leading global pharmaceutical company to utilise the NavigAID autoimmune disease characterisation panel to explore the autoantibody profiles of patients with four key autoimmune diseases
• Agreements with three leading global pharmaceutical companies to utilise the SeroTag immuno- oncology discovery array to explore the autoantibody binding profiles of solid tumour cancer patients treated with immunotherapy
• Renewal of existing partnership with Oncimmune continuing to provide autoantibody biomarker services to a global pharmaceutical company, with two initial projects started to profile patients in autoimmune trials
• Further research published in leading journals including Arthritis Research & Therapy1 and PLOSOne2, alongside pre-publication of the first results from collaboration with Cedars-Sinai3

EarlyCDT Lung

• Pilot in Norfolk and Waveney Clinical Commissioning Group initiated, representing the first sales of the EarlyCDT Lung test into the NHS
• iDx Lung4 programme launched, with 350 patients recruited to date in Southampton and Leeds
• US partner for EarlyCDT Lung, Biodesix, seeing a recovery in demand, with planned expansion of its national sales team from 32 to 76 by the end of 2022
• EarlyCDT Lung authorised for use by the Spanish Public Health Service with the Galician Health Service (SERGAS), the first public health service in Spain to use the EarlyCDT Lung test
• Diagnosticos da America, Latin America's largest medical diagnostic company, to offer EarlyCDT Lung across its extensive laboratory, private hospital and clinic network
• Successful return of the IP and distribution rights for EarlyCDT in the People's Republic of China and Hong Kong from Genostics Company Limited, allowing Oncimmune to pursue the optimum route to market

1

• Results from the ECLS study published in the European Respiratory Journal5 and pre-publication of the three-yearfollow-up data6 supports a trend towards a mortality benefit of the EarlyCDT Lung blood test, confirming the number of late-stage cancers and deaths to be lower in patients tested with EarlyCDT Lung
• Additional results published in PLOSOne showed that EarlyCDT Lung and CT surveillance has been found to be highly cost-effective in early detection compared to CT surveillance alone7

Financial highlights:

• Revenue of £3.7M (FY2020: £0.5M) validates the Company's core strategy of focusing on building a leading immunodiagnostics group; with significant growth driven by conversion from an expanding pipeline of ImmunoINSIGHTS opportunities
• The revenue reported is lower than the headline £5.6M indicated in the unaudited full-year trading update issued on 8 June, due largely to revenue recognition relating to an invoice for £1.7M to an historic EarlyCDT Lung distributor. The Group is unable to recognise this revenue in the year ended 31 May 2021 as the revenue recognition requirements of IFRS 15 have not been met at this time
• The ImmunoINSIGHTS service business showed strong growth in revenue, profitability and cash generation during the period
• Successful equity placing in March 2021 with gross proceeds of £9M to enable a 4x scale-up in ImmunoINSIGHTS operating capacity to meet increasing demand from customers, and the expansion of commercial team to support customers, particularly in the US
• Continued tight management of cost base following the cost reduction programme initiated in 2018

Recent progress and FY2022 outlook:

• Scale up of the Dortmund facility in progress and capable of handling upwards of 40,000 samples per annum by Q1 FY2023
• Continued commercial success from the infectious diseases platform across existing and new contracts
• Commercial sales team expansion in the US underway with recent key hires on the East and West coasts. With a clear majority of all ImmunoINSIGHTS contracts currently and historically being awarded are from the US
• Evaluating additional expansion of scientific and bioinformatics capability in the US to deliver US- based projects
• Second pilot to provide EarlyCDT Lung tests into the NHS already signed and expected to commence in Q3 FY2022
• After quieter than expected summer months in which fewer new ImmunoINSIGHTS contracts were signed than originally expected, there has been a healthy resumption of activity and a strong rate of conversion of the commercial pipeline into service contracts, underpinning confidence in FY2022 revenue growth from both new opportunities and follow-on contracts
• Longer term prospects remain compelling, with the conversion of a number of initial services contracts into multiple projects serving to demonstrate the Group's ability to develop deeper and broader strategic commercial partnerships, of increasing value and longevity

Dr Adam M Hill, CEO of Oncimmune, commented: "We are pleased to announce our full year results for the 2021 financial year. Over the period, the ImmunoINSIGHTS business has allowed us to broaden our pipeline of opportunities whilst deepening our engagement with key customers. As demonstrated by the number of follow-oncontracts being signed and our growing commercial pipeline, we are experiencing increased recognition for our services by our partners and customers. With significant momentum moving into the second quarter of FY2022, driven by the highly differentiated ImmunoINSIGHTS service, we look forward to another year demonstrating the success against our three-yearstrategic plan to unlock the Group's growth potential."

"On behalf of the Board, we would like to thank all our employees for their dedication during a period of high growth and investment despite the impact of COVID-19. We would also like to thank investors for their continuing support through the oversubscribed placing during the period in support of our growth

2

plans and are pleased to be able to report continued strong delivery against the Group's goals over the period."

Investor presentation and conference call

The Company's management team will host a presentation and conference call for analysts at 10:00 GMT today. For conference call details please contact Alexander Davis of FTI Consulting at [e-mail] 020 3727 1000.

The management team will also host on Investor Meet Company a live presentation of the results at 15:00 GMT this afternoon which will be open to all existing shareholders and potential new investors. Access to Investor Meet Company is free and interested parties can register to attend the presentation via the following link: https://www.investormeetcompany.com/oncimmune-holdings-plc/register-investor

1. Vordenbäumen, S., Brinks, R., Schriek, P. et al. Profiling of IgG antibodies targeting unmodified and corresponding citrullinated autoantigens in a multicenter national cohort of early arthritis in Germany. Arthritis Res Ther 22, 167 (2020).https://doi.org/10.1186/s13075-020-02252-6
2. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0241189
3. https://www.medrxiv.org/content/10.1101/2021.07.15.21260603v1
4. NHS Lung Health Check Programmes in Wessex and Yorkshire as part of the iDx-LUNG evaluation programme
5. https://erj.ersjournals.com/content/early/2020/07/09/13993003.00670-2020
6. https://medrxiv.org/cgi/content/short/2021.08.17.21262105v1
7. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237492

For further information:

Oncimmune Holdings plc

Dr Adam M Hill, Chief Executive Officer Matthew Hall, Chief Financial Officer [e-mail]

Singer Capital Markets (Nominated Adviser and Joint Broker) Aubrey Powell, Harry Gooden, George Tzimas, James Fischer [phone]

WG Partners (Joint Broker)

David Wilson, Nigel Barnes, Nigel Birks [phone]

Media enquiries:

FTI Consulting

Ben Atwell, Michael Trace, Alex Davis [e-mail]

[phone]

About Oncimmune (www.oncimmune.com)

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.

3

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

4

CHAIRMAN AND CHIEF EXECUTIVE OFFICER'S REVIEW

We are pleased to report the Group's audited full year results to 31 May 2021 and provide an update on the further operational and strategic progress made since year end.

Oncimmune is a leading immunodiagnostics developer, primarily focused on the growing fields of immuno-oncology, autoimmune disease and infectious diseases. As a specialist immunology testing business, the Group has a diversified and growing revenue stream from its discovery and development service-based platform, delivering actionable insights into therapies to its pharmaceutical and biotech partners, as well as a portfolio of diagnostic products to detect early-stage cancer. 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.

Our understanding of the immune system enables us to harness its sophisticated response to disease in order to detect cancer earlier and to support the development of better therapies. The key to improving disease outcomes is early detection and better selection for therapy. The Group has two operational divisions providing immunodiagnostics services:

• Oncimmune's ImmunoINSIGHTS platform enables life science organisations to optimise drug development and delivery, leading to more effective targeting as well as safer treatments for patients. Our core immune-profiling technology is underpinned by our library of over 8,800 immunogenic proteins, one of the largest of its kind. This helps identify clinical trial participants and patients in clinically relevant subgroups, enabling the development of targeted, more effective treatments with lower risk of adverse events.
• Oncimmune's immunodiagnostic technology, EarlyCDT, can detect and help identify cancer on average four years earlier than standard clinical diagnosis. The Group's 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 believe we are poised to become an integral component of future lung cancer detection programmes, globally.

Business update

The 2021 financial year has been an important one for Oncimmune, delivering our second full year of trading since announcing the Company's three-year strategic plan and demonstrating its impact on the Group's revenue. Launched in September 2018, the strategy is intended to unlock the latent potential of the Group's proprietary technology platform by establishing a pharma partnering services business, ImmunoINSIGHTS. Core to this strategy was the identification of commercial opportunities leveraging Oncimmune's proprietary autoantibody-based technology platform and the Group's revenue growth in FY2021 is a direct result of this service-oriented strategy.

Beyond the growth of in revenues through unlocking value in the platform, the differentiated product and service offering is also creating additional optionality for future growth. Delivering high quality, differentiated results time and time again for our customers on the ImmunoINSIGHTS side of the business has allowed us to not only broaden our pipeline of opportunities, but also deepen our engagement with key customers, increasingly contributing to the biomarker strategy in support of both pre-clinical and clinical drug development as a valued partner.

As a result of the COVID-19 pandemic and subsequent restrictions imposed globally, since March 2020 the Company has been working remotely where possible to minimise the potential impact on the business, whilst ensuring all laboratory operations are unaffected. Within our Nottingham and Dortmund facilities we organised the staff's working arrangements to mitigate the possible effects on the business and our customers and are pleased to report that COVID-19 has not materially affected our laboratory output.

We would like to take this opportunity to thank our staff, suppliers, and customers for their resourcefulness and resilience over the last year in continuing to deliver against the Group's strategy

5