Human trials of Covid-19 vaccines could start without normally essential animal-studies data
Medicines regulators around the world have agreed to ease stringent rules that normally govern putting vaccines into human trials, as research groups around the world race to develop jabs against the ongoing coronavirus pandemic.
Potential vaccines for the coronavirus may skip some steps normally considered essential, such as gathering efficacy data from animals before they are given to human subjects.
“They are changing things in a material way, away from what we would normally do,” said Adam Finn, a vaccines expert and professor of paediatrics at the University of Bristol.
Multiple trials are already underway on potential Covid-19 vaccines.
US biotech company Moderna announced on 16 March that the first participants had received their candidate vaccine, while three further phase 1 clinical trials are currently underway in China, according to ClinicalTrials.gov.
But with no guarantee of success, and research leaders warning that vaccines could take at least 12-18 months to develop, regulators met on 18 March to hammer out how to speed up getting more vaccines into human trials by “striking the balance” between rapid vaccine development and having “enough robust data to enable decision-making”.
The meeting included experts from the World Health Organization, the European Commission, and more than 20 regulatory authorities including the United States Food and Drug Administration and the European Medicines Agency.
The regulators agreed vaccine manufacturers could use data from similar products—such as candidate vaccines for the SARS or MERS viruses—instead of having to generate specific data for each new vaccine against the new coronavirus. In addition, animal trials would not need to show efficacy before a vaccine was tested in humans, though animal data on immune response would be necessary.
Experts say safety will not be compromised though.
“No-one is going to cut corners on patient safety during clinical trials,” said Sheuli Porkess, director of research, medical and innovation at the Association of the British Pharmaceutical Industry.
Ohid Yaqub from the University of Sussex Business School agreed, saying, “FDA and EMA tolerance for risk is extremely low, and I don’t think even a pandemic situation changes that.”
Changes to regulatory barriers are more likely to lead to issues with efficacy, rather than safety. Charlie Weller, head of vaccines at Wellcome, points out that each candidate vaccine will still be assessed on a case-by-case basis, and regulators are taking a “pragmatic approach” to enable efficiencies only when justified by the data.
Stephen Evans, a former EMA committee member at the London School of Hygiene and Tropical Medicine, said regulators were criticised for slowing the arrival of vaccines after the 2014 Ebola outbreak.
“They are conscious of criticism,” he said, so they are making sure there is solid evidence that any regulatory barrier to a vaccine being available should have prevented problems in the past.
But researchers will still need to tread carefully.
At the 18 March meeting, the regulators agreed that some candidate vaccines could be tested in humans without normally required data from animals on whether a vaccine could enhance the severity of the disease.
Such disease enhancement was encountered in early animal vaccine studies during the SARS epidemic in 2003, so any lowering of requirements on disease enhancement for Covid-19 is “potentially risky”, says Finn.
Whether the new flexibility will result in successful vaccines being developed on a shorter timescale remains to be seen. Finn says it could, “but it’s completely contingent on the vaccines actually working”.
A version of this article also appeared in Research Europe