AstraZeneca Plc has put a hold on the late-stage trial of its highly anticipated COVID-19 vaccine candidate in development with the University of Oxford after a serious adverse reaction in a study participant, health news website Stat News has reported.
The AstraZeneca-Oxford partnership is a frontrunner in the race for a COVID-19 vaccine. Stat News quoted an AstraZeneca spokesperson and two unnamed sources familiar with the matter to describe the hold as a temporary "pause" in the large-scale trial required for United States regulatory approval.
The spokesperson described the pause as "a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials, while it is investigated, ensuring we maintain the integrity of the trials."
The spokesperson also said that the company is "working to expedite the review of the single event to minimize any potential impact on the trial timeline."
The nature of the adverse reaction and when it happened were not disclosed, though the participant is expected to recover, an individual familiar with the matter told Stat News.
Clinical holds are not uncommon, and it is unclear how long AstraZeneca's might last. The progress of the company's trial - and those of all COVID-19 vaccines in development - are being closely watched given the pressing need for new ways to curb the global pandemic.
Separately, nine leading US and European vaccine developers pledged on Tuesday to uphold the scientific standards that their experimental immunisations will be held against, amid a hurried global race to contain the pandemic, the Reuters news service reported.
AstraZeneca's is the first phase-three COVID-19 vaccine trial known to have been put on hold. Shares of the company fell more than six percent in after-hours trading on the New York Stock Exchange.
The companies, including Pfizer, GlaxoSmithKline and AstraZeneca, in a joint statement made a "historic pledge ... to uphold the integrity of the scientific process as they work towards potential global regulatory filings and approvals of the first COVID-19 vaccines".
The unusual move to promise to play by well-established rules underlines the highly politicised debate over what action is needed to quickly rein in the spread of the deadly disease and to jump-start global business and trade.
The head of the US Food and Drug Administration said last month that the normal approval process may be bypassed for a COVID-19 vaccine as long as officials were convinced the benefits outweigh the risks, prompting a call for caution from the World Health Organisation.
Developers globally have yet to produce large-scale trial data showing actual infections in participants, yet Russia granted approval to a COVID-19 vaccine last month, prompting some Western experts to criticise a lack of testing.
The head of China's Sinovac Biotech said most of its employees and their families have already taken an experimental vaccine developed by the Chinese firm under the country's emergency-use programme.
