The world’s first human challenge trial for the coronavirus will launch in January in the United Kingdom, spearheaded by established challenge trial company hVivo, a subsidiary of Irish pharmaceutical company Open Orphan (ORPH.L).
Human challenge trials, also called controlled human infection studies, involve the deliberate infection of healthy volunteers in order to study a condition or treatments. Though challenge trials are themselves not new, they present a complex and controversial path to testing new vaccines and treatments for COVID-19.
The strategy is to find a dose that results in visible symptoms, and use that dose to conduct trials for pharmaceutical products. This is achieved by quarantining participants and injecting them, followed by an observation period.
hVivo will start off with a small dose and increase the amount in each subsequent set of participants until the optimal dose is reached. After that, the company can set the template to help drug companies test new products for COVID-19, according to chief scientific officer Andrew Catchpole.
The strategy has its pros and cons, according to experts. On the plus side, it reduces the need for tens of thousands of volunteers to test a vaccine, because a smaller set of trial participants can be used — about 100 compared to 30,000 or more. This, in turn, speeds up the clinical trial process.
On the negative side, the trials have limitations since they cannot be conducted in vulnerable individuals. That stands in the way of diversifying clinical trial enrollees—of particular focus in the U.S. And there is no known effective treatment for COVID-19 yet, which means there is no safety net. This last point is the reason for controversy in the scientific community.
But Catchpole told Yahoo Finance with Gilead Science’s (GILD) remdesivir, also known as Veklury, and dexamethasone in use in hospitals these days, there are at least some options. An Oxford University trial of dexamethasone proved it was effective, while there has been less enthusiasm around remdesivir, most recently in a trial conducted by the World Health Organization.
In the summer, health agencies weighed on the idea. The National Institute of Allergy and Infectious Diseases (NIAID), lead by Dr. Anthony Fauci, outlined some of the pros and cons.
“A model of disease in healthy young volunteers may have questionable scientific validity when extrapolated to older or other at-risk populations that have disproportionate morbidity. Moreover, correlates of protection from SARS-CoV-2 are poorly understood and may vary with the population or the vaccine construct,” according to NIAID.
The World Health Organization, meanwhile, pointed out in a May report, the minimal benefit of such trials since the trial population would be limited.
“In those aged 18-30 years (whether healthy or not), hospitalization rates for COVID-19 are currently estimated to be around 1% and fatal infection rates around 0.03%,” the authors wrote.
Dr. Arthur Caplan, a bioethicist and professor at NYU Langone Health, told Yahoo Finance that back in March, many drug companies were against the idea, saying such trials would be too risky. But that’s changing now. In addition, NIAID recently revealed it has been preparing for the possibility of running a challenge trial.
And even with several vaccines in late stages of clinical trials, the remainder of the more than 180 candidates globally are likely to benefit if a human challenge trial is used.
Caplan, who is on the advisory board of 1DaySooner, which has advocated for such trials and has thousands of petitioners who say they would sign up for one, said it still makes sense to pursue, because “we still don’t know if the first round of vaccines will work.”
hVivo’s Catchpole said the challenge trial “can really expedite judging the efficacy of a vaccine in a safe and informative way.”
A traditional clinical trial stops when a certain number of infected individuals is reached — and if a majority of those infected are in a placebo group, the vaccine is considered a success. But it also depends on participants’ habits and locations — if they are in a hotspot or are roaming around in the middle of one intentionally trying to expose themselves, versus if they are in the middle of a low-incidence area or are following safety protocols.
Catchpole said that since the company announced it intentions in March, it began working on the strategy and protocols with experts. In addition, hVivo is working closely with the U.K. government.
Cathal Friel, hVivo’s executive chairperson, told Yahoo Finance that in addition to the U.K. launch, the company is also in final stages for establishing a quarantine center in Australia, and “shortly thereafter, in North America.” But where on the continent has yet to be revealed. In both cases, hVivo would be partnering, rather than running, the trials.
It also remains unclear which, if any, vaccine companies will participate with hVivo once they set up the template.
The U.K. government is funding the trial with about $13 million (or £10 million) and is preparing to invest up to $43.4 million, pending a regulatory review. The trial is being done in coordination with Imperial College London and Royal Free London NHS Foundation Trust.
More from Anjalee: