Open Orphan plc announced that hVIVO, a subsidiary of Open Orphan, has signed a £10.4 million contract with an existing top 5 global pharmaceutical client to manufacture a new batch of H1N1 influenza challenge virus, leveraging off an existing in-house generated challenge model, and to conduct a human challenge trial to test the client's antiviral product. hVIVO has world-leading expertise in challenge agent manufacture, with the ability to manufacture specific subtypes of viruses, as well as unrivalled experience in conducting challenge studies. Since the COVID-19 pandemic, the Company has seen an increase in the number of clients looking to test their vaccines and antivirals against specific subtypes of viruses that are circulating in the population or that have the potential to be widely spread.

As a result, there is a greater interest in end-to-end human challenge contracts such as this, that include a novel challenge agent manufacture and a challenge study. The study willevaluate the efficacy profile of the antiviral against the specific influenza subtype, generating data quickly and efficiently. This is the third human challenge contract signed with this client, highlighting the Company's world leading expertise and the clear benefits of human challenge trials to Big Pharma's drug development process.

Good Manufacturing Practice ("GMP") compliant virus manufacturing activities will commence immediately and are expected to complete by Second Quarter 2023. Once completed, hVIVO will conduct a Phase 2a double-blinded placebo-controlled human challengestudy which is expected to be completed by Fourth Quarter 2023. hVIVO will recruit healthy volunteers via the Company's dedicated volunteer recruitment arm, FluCamp.

The majority of revenue from the contract is expected to be recognised during 2023.