Oxford BioDynamics plc

("Oxford BioDynamics" or the "Company")

OBD's EpiSwitch CiRT Proven to Impact Clinical Treatment Decisions in Published Study

·      Results strongly support CiRT's clinical utility in guiding immunotherapy decisions across a broad range of solid tumors

·      CiRT test influenced real-world treatment choices in 61% of cases

·      Company plans to apply for inclusion in US National Comprehensive Cancer Network clinical guidelines later this year

Oxford, UK - 04 September 2025 - Oxford BioDynamics Plc (AIM: OBD), a precision clinical diagnostics company bringing specific and sensitive tests to the practice of medicine based on its EpiSwitch® 3D genomics platform, announces the publication of interim results from its milestone FDA-registered PROWES trial (NCT06635954). The study, published in the high-impact medical journal Cancers¹, demonstrates the clinical utility and treatment impact of its EpiSwitch CiRT (Checkpoint inhibitor Response Test).

The peer-reviewed publication of the ongoing PROWES prospective real-world study evaluated the clinical utility of OBD's CiRT blood test in guiding treatment decisions for 205 patients receiving immune checkpoint inhibitors (ICIs) across a broad range of advanced solid tumours. CiRT is a clinically validated blood test that predicts a cancer patient's likely response to ICIs, with high sensitivity (93%), specificity (82%) and accuracy (85%), across the most widely used ICIs^2-3.

Thomas Guiel, COO of Oxford BioDynamics, said: "The PROWES results represent a significant milestone that further validates the transformative real-world impact of the EpiSwitch CiRT test on decision-making in real clinical practice.

 "These results not only strengthen the scientific foundation of CiRT, but also support our strategy to secure inclusion in NCCN (National Comprehensive Cancer Network) clinical guidelines. The Company expects to apply for inclusion later this year, which is a critical step towards driving widespread adoption and achieving our commercial objectives."

The findings show that CiRT influenced oncologists' treatment choices in 61% of cases-including key decisions to initiate, escalate, de-escalate, or avoid therapy. Among patients with a Low Probability of Response CiRT result, nearly half avoided ineffective treatment, reducing unnecessary exposure to potentially serious or life-threatening toxicity. Conversely, almost three-quarters with a High Probability of Response had their treatment continued or escalated.

The study further demonstrated that CiRT results closely matched real-world patient outcomes and had broad applicability, remaining consistent across race, ethnicity, socioeconomic status, and whether treatment was in a major medical centre or community practice. Unlike existing invasive tissue-based tests, such as PD-L1 expression or genetic testing (TMB, MMR/MSI), often limited by poor predictive power, tumour type, and require biopsy or surgical access, CiRT provides a universally applicable, minimally invasive, easy-to-interpret result based on a patient's personal immune system readiness. Patients having a Low Probability of Response were significantly more likely to experience disease progression, whereas those with High Probability were more likely to respond with longer-lasting disease control.

Early data also suggest CiRT may be used as a tool to monitor emerging resistance to ICIs, as some patients showed shifts from High to Low Probability of Response that matched their disease progression.

These findings underscore CiRT's potential to personalise care pathways, improve patient outcomes and deliver significant cost efficiencies. Given that ICIs and supportive care costs can exceed $850,000 per patient, there is a substantial opportunity for savings by avoiding costs associated with ineffective treatment and related adverse events. The authors highlight that stopping an ineffective therapy just one or two cycles earlier saves many multiples of the cost of the CiRT test.

CiRT is available privately in the UK, covered by Bupa, and in the US with a unique PLA reimbursement code.

The peer-reviewed manuscript, titled "Clinical Utility of the EpiSwitch CiRT Test to Guide Immunotherapy Across Solid Tumors: Interim Results from the PROWES Study", is available online: www.mdpi.com/3483654

References:

[1] Abdo, J., Berghausen, J., et al. (2025). Clinical Utility of the EpiSwitch CiRT Test to Guide Immunotherapy Across Solid Tumors: Interim Results from the PROWES Study, Cancers. https://www.mdpi.com/3483654

[2] Hunter, E., Salter, M., et al. (2023). Development and Validation of Blood-Based Predictive Biomarkers for Response to PD-1/PD-L1 Checkpoint Inhibitors: Evidence of a Universal Systemic Core of 3D Immunogenetic Profiling across Multiple Oncological Indications. Cancers. https://doi.org/10.3390/cancers15102696

[3] Ouf, M., Aggarwal, N., et al. (2025). Evaluation of EpiSwitch in predicting immunotherapy response in hepatocellular carcinoma and gastrointestinal tumours. Journal of Clinical Oncology. https://doi.org/10.1200/JCO.2025.43.4_suppl.623

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Notes for Editors

About Oxford BioDynamics Plc

Oxford BioDynamics Plc (AIM: OBD) is an international biotechnology company, advancing personalized healthcare by developing and commercializing precision clinical diagnostic tests for life-changing diseases.

Currently OBD has two commercially available products: the EpiSwitch® PSE (EpiSwitch Prostate Screening test) and EpiSwitch® CiRT (Checkpoint Inhibitor Response Test) blood tests. PSE boosts the predictive accuracy of a PSA test from 55% to 94% when testing the presence or absence of prostate cancer. CiRT is a highly accurate (85%) predictive response test to immuno-oncology checkpoint inhibitor treatments.

The tests are based on OBD's proprietary 3D genomic biomarker platform, EpiSwitch® which enables screening, evaluation, validation and monitoring of biomarkers to diagnose patients or determine how individuals might respond to a disease or treatment.

OBD's clinical smart tests have the potential to be used across a broader range of indications, and new tests are being developed in the areas of oncology, neurology, inflammation, hepatology and animal health.

The Group's headquarters and UK laboratories are in Oxford, UK. Its US operations and clinical laboratory are in Maryland, USA, along with a reference laboratory in Penang, Malaysia.

OBD is listed on the London Stock Exchange's AIM (LSE: OBD). For more information, please visit the Company's website, www.oxfordbiodynamics.com,  X (@OxBioDynamics) or LinkedIn.