ORPH.L Regulatory News (ORPH)

6 December 2021

Open Orphan plc

("Open Orphan" or the "Company")

Positive results from Influenza Human Challenge Study conducted by hVIVO

Open Orphan plc (AIM: ORPH) a rapidly growing specialist pharmaceutical services clinical research organisation (CRO) and world leader in vaccine and antiviral testing using human challenge clinical trials, notes the announcement released from SAB Biotherapeutics (NASDAQ: SABS) ("SAB"), reporting positive results from a human challenge study testing SAB-176, its investigational therapeutic for the treatment of seasonal influenza. hVIVO, a subsidiary of Open Orphan, conducted the Phase 2a randomised, double-blinded, placebo-controlled study using its Influenza Human Challenge Study Model.

The trial evaluated the safety and treatment efficacy of SAB-176 in 60 healthy adults challenged with a pandemic influenza strain (pH1N1). Participants were intranasally inoculated with the influenza challenge virus and then randomised to receive either SAB-176 or placebo.. SAB-176 achieved statistically significant (p = 0.026) reductions in viral load. Based on partial data, statistically significant reductions in clinical signs and symptoms compared to placebo were also observed. Additionally, no serious adverse events were reported and SAB-176 appeared to be safe and well tolerated. Based on the positive results from this study, SAB plans to further evaluate SAB-176 in a Phase 2 influenza clinical trial.

Flu is caused by the influenza virus and is one of the most common infectious respiratory diseases and can lead to severe illness, and death. There are four types of seasonal influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease. According to the World Health Organisation (WHO), worldwide, these annual epidemics are estimated to result in about three to five million cases of severe illness, and about 290 000 to 650 000 respiratory deaths.

hVIVO has two decades of experience and expertise in safely conducting challenge studies across a range of respiratory and infectious disease viruses, including respiratory syncytial virus (RSV), Influenza, human Rhinovirus HRV (common cold virus), malaria, and asthma. In October 2020, this expanded to include the SARS-CoV-2 virus.

Cathal Friel, Executive Chairman of Open Orphan, said: "I am pleased that SAB has received positive results for SAB-176 from its influenza human challenge trial, conducted by hVIVO. SAB-176 met its primary endpoint and based on partial data appears to have met a key secondary endpoint. These encouraging results support proceeding to a Phase 2 clinical trial.

"Influenza affects a significant proportion of the global population every year with symptoms ranging from mild to severe, with hospitalisations and deaths occurring among high-risk groups. hVIVO has successfully been delivering Influenza human challenge trials for over two decades, and we look forward to continuing to support Big Pharma and biotechs to provide early proof-of-concept for novel vaccines and antivirals."

Mariya Kalinova, Medical Director, hVIVO, commented: "We are delighted to see these positive results from the Phase 2a Influenza Human Challenge Study for SAB Biotherapeutics' novel anti-influenza human immunotherapy, SAB-176. The encouraging reductions in viral load and clinical symptoms, along with the promising safety and tolerability data observed in this challenge study suggest SAB-176 may have a positive impact on individuals with influenza.

"This successful study demonstrates the way that Phase 2a challenge studies can help advance drug development and provide a value inflection point for innovative products such as SAB-176 as they move towards a full Phase 2 study. Moving forward, we expect to see an increase in the number of human challenge studies taking place across multiple infectious diseases, as interest in these disease areas continues to grow."

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Notes to Editors

Open Orphan plc

Open Orphan plc (London and Euronext: ORPH) is a rapidly growing 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 and its state-of-the-art 24-bedroom QMB clinic with its highly specialised on-site virology and immunology laboratory. The Company has a leading portfolio of human challenge study models for infectious and respiratory diseases and is developing a number of new models. There has been an explosion in the growth of the infectious disease market, which is estimated to grow to in excess of $250bn by 2025. The Group is focused on refreshing its existing challenge models and develop new models, such as Malaria, to address the dramatic growth potential of the global infectious disease market.

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.

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.

About SAB Biotherapeutics

SAB Biotherapeutics, Inc. (SAB) is a clinical-stage, biopharmaceutical company advancing a new class of immunotherapies leveraging fully human polyclonal antibodies. SAB has applied advanced genetic engineering and antibody science to develop transchromosomic (Tc) Bovine™ that produce fully-human antibodies targeted at specific diseases, including infectious diseases such as COVID-19 and influenza, immune system disorders including type 1 diabetes and organ transplantation, and cancer. SAB's versatile DiversitAb™ platform is applicable to a wide range of serious unmet needs in human diseases. It produces natural, specifically targeted, high-potency, human polyclonal immunotherapies. SAB is currently advancing multiple clinical programs. For more information on SAB, visit: https://www.sabbiotherapeutics.com/ and follow @SABBantibody on Twitter.

About SAB-176

SAB-176 is a multivalent, broadly neutralizing fully-human polyclonal antibody therapeutic candidate in development for the treatment or prevention of severe influenza. The novel, specifically-targeted therapeutic leverages the natural human biological immune response to specifically bind to Type A and Type B influenza viruses. Like vaccines, it can be modified to address annual strain changes, when needed, to maintain broader coverage as the flu virus mutates. Preclinical data suggests that SAB-176 offers broad protection against diverse influenza strains.

SAB's novel DiversitAb™ immunotherapy platform enables the production of large amounts of targeted, highly potent human polyclonal antibodies. The platform leverages transchromosomic cattle (Tc Bovine™) that have been genetically designed to generate fully human antibodies (immunoglobulin G) rather than bovine antibodies, in response to inoculation with an immunogen.

To develop and produce SAB-176, Tc Bovine were hyperimmunized with a quadrivalent antigen, including a number of influenza strains. Within a brief period of time, the Tc Bovine generated significant amounts of fully-human antibodies to combat the virus, driving titers beyond the levels known to be protective. Plasma was collected (in a similar manner as from human plasma donors), then purified to isolate the antibodies that comprise the therapeutic treatment.