The agency requested data this week, following the pause of large-scale international assessment after a non-fatal serious adverse event was reported in a UK participant earlier this month.
Scrutiny into the safety of the AstraZeneca and University of Oxford investigative coronavirus 2019 (COVID-19) vaccine candidate has not yet been eased.
The US Food and Drug Administration (FDA) has started investigation into a serious adverse event reported by a UK-based volunteer participant in the phase 3 trial for adenovirus AZD1222, initially reported in the first week of September.
According to Reuters, the agency anticipates to receive requested safety data later this week, at which time they will conduct its own analysis.
The 30,000-plus participant international late-stage assessment was put on hold when the patient was hospitalized with a non-fatal illness linked to the vaccine, but since resumed in the UK, Brazil, India, and South Africa.
The FDA intends to determine whether similar adverse events have emerged in trials conducted by investigators at Oxford, according to a source, in an effort to remain “thorough” of potential COVID-19 candidates.
In the initial report of the data request, the FDA declined to comment, and Oxford University did not respond to requests to comment. A spokesperson with AstraZeneca said the company is continuing to work with the FDA to “facilitate review of the information needed to make a decision regarding resumption of the US trial.”
AZD1222 was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of an adenovirus that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein.
In July, the pharmaceutical company reported interim results from their ongoing phase 1/2 trial showing AZD1222 was generally tolerable, and generated robust immune responses against the SARS-CoV-2 virus in all evaluated participants.
Earlier this month, AstraZeneca was among 9 pharmaceutical companies to sign a letter pledging the continued assurance and monitoring for safety and tolerability in the first COVID-19 vaccine candidates, in response to reports that a vaccine may be regulated and distributed in alignment with the upcoming US Presidential Election in November.
A federal $1.2 billion pledge to support AZD1222 research and development includes an agreement for 300 million doses for the US population.