Open Orphan plc

("Open Orphan" or the "Company")

Completion of Nominated Adviser due diligence

Open Orphan plc (AIM: ORPH), a rapidly growing specialist contract research organisation (CRO) and world leader in testing infectious and respiratory disease products using human challenge clinical trials, announces that further to the appointment of Liberum Capital Limited ("Liberum") as its Nominated Adviser and Joint Broker on 28 April 2022, Liberum has confirmed that is has completed its due diligence .

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Notes to Editors

Open Orphan plc (London and Euronext: ORPH) is a rapidly growing contract research company that is a world leader in testing infectious and respiratory disease products using human challenge clinical trials. The Company provides services to Big Pharma, biotech, and government/public health organisations.

The Company has a leading portfolio of human challenge study models for infectious and respiratory diseases and is developing a number of new models, such as malaria and COVID-19, to address the dramatic growth of the global infectious disease market. The Paris and Breda offices have over 25 years of experience providing drug development services such as biometry, data management, statistics CMC, PK and medical writing to third party clients as well as supporting the London-based challenge studies.

Open Orphan runs challenge studies in London from its Whitechapel quarantine clinic, its state-of-the-art QMB clinic with its highly specialised on-site virology and immunology laboratory, and its newly opened clinic in Plumbers Row. To recruit volunteers / patients for its studies, the Company leverages its unique clinical trial recruitment capacity via its FluCamp volunteer screening facilities in London and Manchester. The newly opened facilities have expanded the scope of the business to enable the offering of Phase I and Phase II vaccine field trials, PK studies, bridging studies, and patient trials as part of large international multi-centre studies.

Building upon its many years of challenge studies and virology research, the Company is developing an in-depth database of infectious disease progression data. Based on the Company's Disease in Motion® platform, this unique dataset includes clinical, immunological, virological, and digital (wearable) biomarkers.