- AstraZeneca is the latest coronavirus vaccine developer to start a large-scale efficacy study in the U.S., announcing late Monday that it has begun a Phase 3 trial testing the shot it licensed from the University of Oxford.
- The study, the third of its type to get underway in the U.S., will test whether AstraZeneca and Oxford's vaccine can prevent symptomatic COVID-19 in adults. Volunteers will receive two shots, given four weeks apart, of either the vaccine or a placebo. Two-thirds of them will get the vaccine.
- The trial's start follow multiple reports the Trump administration has considered an emergency authorization of AstraZeneca and Oxford's vaccine before the U.S. presidential election, and prior to obtaining data from the Phase 3 trial. In a separate statement, AstraZeneca CEO Pascal Soriot appeared to address those reports by vowing the company is "moving quickly without cutting corners."
Early studies of several experimental coronavirus vaccines, among them AstraZeneca's shot, have only shown they can spur immune responses and are safe enough to test further. It's not yet known whether they'll actually protect people against COVID-19, or if unexpected side effects might occur. That's the purpose of lengthy, large-scale efficacy trials in tens of thousands of participants, a standard and critical part of vaccine testing.
But as the pandemic has raged on, the urgency to speed a vaccine to market — and for various governments to secure access to them, or claim political victories from research progress — has intensified.
The pressure has led to heightened tension over when to grant approvals. Russia, for instance, cleared a vaccine for use in August, before that shot was studied in large trials. China approved a vaccine for military use and said it began inoculating citizens at high risk of infection with a different shot in July.
In the U.S., the pressure to address the coronavirus pandemic has been compounded by the approaching presidential election. The country leads the world in coronavirus cases and deaths, and progress on a vaccine could be a potent political message come November.
In a recent interview, Food and Drug Administration commissioner Stephen Hahn told the Financial Times he'd be willing to clear a vaccine before Phase 3 trials were finished, as long as the benefits outweighed the risks.
Moderna and the team of BioNTech and Pfizer have already begun Phase 3 studies of their respective vaccines, with early results potentially available this fall. However, recent reports have indicated AstraZeneca's vaccine, which has been more extensively studied outside the U.S., could be fast-tracked before the election.
This past weekend, an article from a local Florida outlet claimed AstraZeneca's planned study in the U.S. was on hold due to "political pressure," namely that the FDA was considering authorizing the vaccine based on data from smaller trials conducted overseas. A conflicting report, in Wisconsin, said the study was set to begin.
Adding to the drama was a controversial emergency approval by the FDA of convalescent plasma for COVID-19, which occurred a day after President Trump publicly chastised the agency and after Trump, at a press conference, claimed politics delayed earlier clearance of the treatment.
In a statement on the start of the U.S. trial, AstaZeneca pledged that any regulatory filing for the vaccine "will meet the stringent requirements established by regulators everywhere around the world."
"We are moving quickly but without cutting corners," CEO Pascal Soriot said in the statement.
The trial, which will enroll up to 30,000 volunteers, is similar in size to Moderna's and Pfizer's. The primary completion date for the study is set for December, according to the clinicaltrials.gov database, though progress will depend on the rates of infection among participants.
AstraZeneca aims to enroll people with an increased risk of infection with SARS-CoV-2. Though the study's main goal is to measure whether the vaccine can prevent symptomatic COVID-19, investigators will also evaluate if the shot can prevent severe COVID-19 or coronavirus infection, as well as reduce emergency room visits. Participants will be tracked for two years.
The FDA has said the bar for approval is results showing a vaccine to be 50% better than a placebo at preventing coronavirus disease or decreasing its severity.
AstraZeneca's vaccine uses a modified virus — a form of an adenovirus that causes common colds in chimpanzees — to deliver genetic instructions meant to spur an immune response against the coronavirus. Results from early testing were published in The Lancet in July, and suggested a two-shot regimen may be more effective than a single dose. AstraZeneca is testing that regimen in the Phase 3 study.