AstraZeneca resumes COVID-19 vaccine trials

AstraZeneca announced that clinical trials of its experimental COVID-19 vaccine AZD1222 have resumed in the UK following confirmation by the Medicines Health Regulatory Authority (MHRA) that it was safe to do so. "On 6 September, the standard review process triggered a voluntary pause to vaccination across all global trials to allow review of safety data by independent committees, and international regulators. The UK committee has concluded its investigations and recommended to the MHRA that trials in the UK are safe to resume," AstraZeneca said.

The trials had recently been put on hold due to a possible safety issue, with the company noting at the time that the move was "a routine action which has to happen whenever there is a potentially unexplained illness in one of the trials." (For related analysis, see ViewPoints: AstraZeneca proves COVID-19 vaccines aren’t too big to fail.)

AstraZeneca further noted that together with the co-developer University of Oxford, as the trial sponsor, it cannot disclose further medical information.

The Phase III programme evaluating AZD1222 is looking to recruit a total of up to 50,000 participants globally with results expected later this year. AstraZeneca announced recently that it had launched a Phase III study in the US, while late-stage testing had already begun in the UK, Brazil and South Africa, with plans to expand to other countries. Brazil's health regulator Anvisa said it had approved the resumption of tests of the vaccine in the country after receiving official information from AstraZeneca. 

Second pause of study

In July, interim data from a Phase I/II trial published in The Lancet showed that the vaccine was well tolerated with no early safety concerns, and that it also triggered a robust immune response against SARS-CoV-2 in all evaluated participants. However, the study was stopped that month for several days after a participant developed neurological symptoms that turned out to be an undiagnosed case of multiple sclerosis, which the researchers said was unrelated to the vaccine. 

UK Health Secretary Matt Hancock welcomed the restart of the trial, noting it was "good news for everyone" that the trials are "back up and running." He added that "this pause shows we will always put safety first. We will back our scientists to deliver an effective vaccine as soon as safely possible." Meanwhile, CEO Pascal Soriot said recently that a vaccine "by the end of this year, early next year" was still possible. "I still think we are on track for having a set of data we would submit before the end of the year and then it depends how fast regulators will review it and give approval,” he said. 

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