Malaria Human Challenge Model

9 August 2021

Open Orphan plc

("Open Orphan" or the "Company")

Development of Controlled Human Malaria Infection Human Challenge Study

hVIVO to assist in the advancement of antimalarial drug and vaccine candidates from November 2021

Open Orphan plc (AIM: ORPH), a rapidly growing specialist clinical research organisation (CRO) and world leader in testing vaccines and antivirals using human challenge clinical trials, announces that its subsidiary, hVIVO, has developed a Controlled Human Malaria Infection ("CHMI") challenge model, both strengthening and further diversifying the Company's world leading portfolio of viral challenge study models. The Malaria challenge model will assist in the advancement of antimalarial drug and vaccine candidates from November 2021. Results from CHMI modelling of drug and vaccine efficacy have previously shown good translation into the field.

Malaria is a serious and life-threatening disease prevalent across much of tropical and sub-tropical Asia, South America and Sub-Saharan Africa. Due to increasing resistance to current antimalarial regimens, new drugs are required as both stand-alone and partner therapies to address a growing unmet medical need. In addition, novel combinations of existing drugs may be required to fill the gap until pipeline candidates can be safely progressed to market. New drugs and combination therapies are required to not only reduce mortality and morbidity in susceptible, primarily paediatric populations, but also to help the move towards a greater goal of malaria elimination.

hVIVO has secured access to a unique, GMP-manufactured P. falciparum sporozoite challenge agent ("PfSPZ Challenge") for use in its malaria challenge studies. PfSPZ Challenge has been used in multiple clinical trials in the United Kingdom, United States, Europe, Indonesia and Africa. As of June 2021, 1,204 volunteers have received 2,011 doses of PfSPZ Challenge (NF54) with no unresolved serious adverse event, sequelae, or deaths to date. Controlled Human Malaria Infection by Direct Venous Inoculation has largely replaced the traditional method of CHMI (mosquito bite), owing to its superior predictability and safety profile. Reported symptoms are mostly mild to moderate and include headache, fever, nausea and fatigue.

Cathal Friel, Executive Chairman of Open Orphan, said: "Malaria is a disease of huge unmet need around the world, with 229 million cases and 409,000 deaths caused in 2019. Its prevention and cure is a designated World Health Organization target. We are pleased to have formally announced today the latest addition to our portfolio of human challenge models namely the Malaria Human Challenge Study Model. The safety profile of PfSPZ is impressive, and we are optimistic that it will enable us to assist in the advancement of antimalarial drug and vaccine candidates from November. This also adds a new challenge model to our already world leading portfolio of viral challenge study models and continues to build on our global infectious disease expertise."

Interested in becoming a volunteer?

hVIVO recruits many of its volunteers for its challenge study clinical trials through its dedicated volunteer recruitment website, www.flucamp.com. By volunteering to take part in one of our studies in a safe, controlled, clinical environment under expertly supervised conditions you are playing your part to further medical research and help increase the understanding of respiratory illnesses.

Individuals interested in taking part in COVID-19 human challenge study research can learn more at www.UKCovidChallenge.com.

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 ("MAR"). With the publication of this announcement via a Regulatory Information Service, this inside information is now considered to be in the public domain.

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 Notes to Editors

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

Open Orphan runs challenge studies in London from both its 19-bedroom Whitechapel quarantine clinic, opened in February 2021, and its 24-bedroom QMB clinic with its highly specialised on-site virology and immunology laboratory. Open Orphan has a leading portfolio of human challenge study models for infectious and respiratory diseases and is developing a number of other models including the world's first COVID-19 human challenge study model as part of the Human Challenge Programme.

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. The Disease in Motion platform has many potential applications across a wide variety of end users including big technology, wearables, pharma and biotech companies. Following COVID-19 there is now a renewed interest and investment in infectious diseases.

Open Orphan's Paris office has been providing biometry, data management and statistics to its many European pharmaceutical clients for over 20 years. For over 15 years, the Company's Netherlands office has been providing drug development consultancy and services, including CMC (chemistry, manufacturing and controls), PK and medical writing, to a broad range of European clients. Both offices are now also fully integrated with the London office and working on challenge study contracts as well as supporting third party trial contracts.