This morning, Open Orphan (ORPH ) published the results from the world’s first COVID-19 human challenge characterisation study, a partnership led by the firm’s hVIVO subsidiary.

The study, which was funded by the UK Vaccine Taskforce and Department of Health and Social Care (DHSC), with Imperial College London as the UK government’s study sponsor, took place at the National Infectious Disease Facility at the Royal Free Hospital in London.

Today, the specialist contract research organisation, Open Orphan said results have shown that it is safe to conduct COVID-19 human challenge studies in young health volunteers.  

As part of the study, researchers aimed to identify a dose of COVID-19 that caused a safe and reliable infection in unvaccinated volunteers with no prior SARS-CoV-2 infection.

The results of the study detail the outcome of 36 healthy male and female volunteers aged 18-29 years which were infected with the original SARS-CoV-2 strain challenge virus. 

hVIVO clinicians closely monitored volunteers in a controlled quarantined setting and collected disease progression data to provide insights into COVID-19 infection.

Overall, the results of the characterisation study support the safety of the infection challenge model which could theoretically provide a ‘plug and play’ platform for testing therapies and vaccines using the original COVID-19 strain as well as variants of the virus, it explained.

During the study, 18 volunteers (50%) became infected with viral load (VL) rising steeply and peaking at around five days post-inoculation. According to the data acquired, there seemed to be no quantitative correlation noted between the viral load and the symptoms in patients. 

No serious symptoms were reported, while mild-to-moderate cold-like symptoms were reported by 16 (88%) of 18 infected volunteers; including a stuffy or runny nose, sneezing, and a sore throat. Some experienced headaches, muscle/joint aches, tiredness and fever.

Anosmia (lost or changed sense of smell) occurred in 13 (72% of infected) of the volunteers.

Modelling using the study data indicated that regular asymptomatic lateral flow testing (“LFT”) would diagnose infection before 70-80% of infectious virus had been generated. This means that if isolation was triggered, it would decrease community transmission to others, it noted.

Overall, no serious adverse events (SAEs) occurred, and the SARS-CoV-2 human challenge study model was shown to be safe and well tolerated in healthy young adults, it told investors.

With the study disease modelling data completed, and a COVID-19 Human Challenge Model now established, Open Orphan should be able to contract / conduct COVID-19 human challenge studies in 2022, subject to individual ethics and regulatory approvals, it outlined.

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Open Orphan is already developing a Delta strain of the virus in partnership with Imperial College London and funded by the Wellcome Trust, which could be used in future trials.

Addressing shareholders, Open Orphan said the data supports the safety of the infection challenge model which could theoretically provide a ‘plug and play’ platform for testing therapies and vaccines using the original COVID-19 strain as well as variants of the virus.

The company highlighted that the results of the characterisation study, as well as the insights they provide into COVID-19 infection, have “potential implications” for public health.

The study showed that while virus was detected significantly earlier in the throat, peak levels of virus were far higher in the nose, implying a potentially higher risk of viral shedding here, thus underlining the importance of proper facemask use to cover both the mouth and nose.

Additionally, insights into the timeline of infection, with viable virus seen after nine days and 12 days for some, support the isolation periods advocated in most guidelines, it added.

Lateral flow tests (LFTs) were also shown to be a good indicator of whether someone was harbouring a viable virus. Positive LFTs correlated well with lab-confirmed detection of virus, including in those who were asymptomatic, the firm noted, however, the tests were shown to be less effective in picking up lower levels of virus at the very start and end of infection.

Dr Andrew Catchpole, Co-investigator on the study and Chief Scientific Officer of hVIVO, said: “The SARS-CoV-2 characterisation study has provided invaluable insights into the progression of COVID-19 infection in healthy young adults. Importantly the study demonstrated that SARS-CoV-2 challenge studies are safe and well tolerated by the volunteers with no serious symptoms and no Serious Adverse Events (SAEs).”

Catchpole added that the results of the characterisation study  have provided “useful insights which could be used to inform public health decisions on COVID-19 symptoms and virus detection going forward, including isolation periods for infectious individuals, the use of LFTs, and establishing the human challenge platform to investigate further aspects of COVID-19.”

Commenting on the results, Cathal Friel, Executive Chairman of Open Orphan said: “Crucially, we have now successfully established a COVID-19 Human Challenge Model which could be instrumental in accelerating the development of future COVID-19 therapeutics. 

He added: “New variants, such as Omicron, often mean that vaccines and antivirals have to be quickly re-evaluated to ensure effectiveness. Human challenge studies could prove to be the fastest way to compare old and new vaccines and therapies.”

Professor Sir Jonathan Van-Tam, Deputy Chief Medical Officer at Department of Health and Social Care, said characterisation studies like Open Orphan’s can offer “a real advantage because the timing of exposure to the virus is always known exactly, therefore things like the interval between exposure and the profile of virus shedding can be accurately described.”

Dr Sir Michael Jacobs, consultant in infectious diseases at the Royal Free London, added:

“The trial has already provided some fascinating new insights into SARS-CoV2 infection, but perhaps its greatest contribution is to open up a new way to study the infection and the immune responses to it in great detail and help test new vaccines and treatments.”

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