Studies on human challenges: UK government signs contract for first clinical trials


Up to 19 volunteers at a time will participate in the tests, which will be held at the Royal Free Hospital in London, which houses a level 3 biosafety service. They will be led by hVIVO, a medical research company specializing in performing tests. by provocation, in partnership with Imperial College London.

These clinical trials will be a little different from most.

For the current Covid-19 vaccine candidates which are in phase 3 – the last stage of testing – tens of thousands of volunteers receive an experimental vaccine and then released to live their daily lives; researchers assume that a certain percentage of them will be naturally exposed to the virus.

In a challenge trial, on the other hand, participants are deliberately given doses of the virus.

Supporters of provocative trials say they are more effective, requiring far fewer volunteers – likely hundreds – because researchers know for sure that everyone will be exposed to the virus and that they can provide scientific data faster.

Critics worry about exposing people to a virus for which there is no safe cure, and say healthy young volunteers are not representative of the general population.

“We are doing everything we can to fight the coronavirus, including supporting our best and brightest scientists and researchers in their quest for a safe and effective vaccine,” said Alok Sharma, UK business secretary. United.

“The funding announced today for these groundbreaking but carefully controlled studies marks an important next step in building our understanding of the virus and accelerating the development of our most promising vaccines that will ultimately help us begin our return to life. normal. “

Characterization study

As a first step, hVIVO, a subsidiary of the Irish company Open Orphan, will conduct a characterization study in early 2021. This consists of deliberately exposing a small number of healthy volunteers to the coronavirus, in order to determine the minimum dose that leads to infection symptoms.

“We want to know up front how the human body reacts to a dose of the virus,” Dr. Martin Johnson, senior medical director of hVIVO, told CNN.

The company expects to be able to test the efficacy of up to three vaccine candidates next year.

A September article in the New England Journal of Medicine claimed that challenge trials could “accelerate the development of subsequent rounds of vaccine candidates” and help researchers better see how the virus attacks the human body.

Several potential vaccines are already nearing the end of traditional phase 3 trials using “natural” exposure to the virus, but just showing that the vaccine has some efficacy in preventing the onset of Covid-19 does not mean that’s the best that scientists can do.

Most people try to avoid Covid-19. But thousands of people sign up to be deliberately reported

The characterization study and vaccine trials will still require ethical approval from UK regulators. England’s Health Research Authority told CNN it has already set up an ethics committee to assess any proposed challenge trial.

Volunteers will be carefully screened to ensure that they are in good health, with no pre-existing conditions. They will need to be between the ages of 18 and 30, says hVIVO. They will be compensated for their participation, but regulators will want to make sure the amount does not appear coercive.

The volunteers will remain in residence at the Royal Free Hospital for the duration of the trial, which could last for several weeks. HVIVO has isolated a strain of the virus taken from a British Covid-19 patient and will expose volunteers to the virus through the nose, using a pipette.

“We’re actually going to take the smaller dose,” Dr. Johnson said. “What we’re trying to do is try to get the minimum number of symptoms safe.”

As soon as a patient shows symptoms of Covid-19, he said, doctors will administer the antiviral remdesivir. HVIVO scientists point out that unlike coronavirus patients who are admitted to hospital, challenge volunteers will be treated at the first sign of infection.

However, no treatment has been shown to help patients early in the course of the virus.

Vaccine trials

Once the characterization study is complete, hVIVO will prepare to test up to three candidate vaccines, as determined by the UK government-led vaccine working group.

Those candidates could be vaccines not yet in Phase 3 trials or field-tested vaccines for which scientists want more data, Dr Johnson said.

Provocation trials are not new and have been carried out for cholera, typhoid, malaria and even influenza. But unlike these diseases, we do not yet have a fully effective treatment against Covid-19, if the experimental vaccine fails.

Dr Johnson said a challenge study for the coronavirus is only possible now because of the promising performance of treatments like the steroid remdesivir and dexamethasone.

The World Health Organization recently found that remdesivir does not appear to save the lives of Covid-19 patients or help them recover faster, and there is no data to suggest that it helps patients early in the day. ‘infection. Current recommendations indicate that dexamethasone should not be given to patients unless they are critically ill.

“The problem is, when you do tests in the wild, you don’t know exactly when a patient got infected. Here we know the second when they actually received the virus. So we can watch it and follow it all the way through, ”Johnson said.


The announcement comes as tens of thousands of people around the world have expressed interest in volunteering for a study on the human challenge of coronaviruses through the 1 Day Sooner organization. hVivo says he’s talking to 1 Day Sooner about identifying potential volunteers.

One of the UK organizers of 1 Day Sooner, 18-year-old Alastair Fraser-Urquhart, told Phil Black earlier this month that challenge studies are “such an instant and common sense idea.”

“The risk for me is minimal. But by taking this small risk on myself, I can potentially protect thousands of other people from infection without consenting to it. “


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