Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaks during a House Select Subcommittee on the Coronavirus Crisis hearing in Washington, D.C.
Erin Scot | Pool | Reuters
White House coronavirus advisor Dr. Anthony Fauci said Wednesday it’s “not uncommon” that AstraZeneca is holding up its coronavirus vaccine trial for a safety review, but the “serious adverse event” with one of the participants is unfortunate.
On Tuesday, AstraZeneca said it paused its phase three trial for a potential Covid-19 vaccine, called AZD1222, due to safety concerns. It’s unclear exactly what the concern is, but a person familiar with the matter told STAT News the hold is related to a “suspected serious adverse reaction” in a participant in the United Kingdom.
“This particular candidate from the AstraZeneca company had a serious adverse event, which means you put the rest of the enrollment of individual volunteers on hold until you can work out precisely what went on,” Fauci said in an interview with Gayle King on CBS This Morning. He added that the company would typically alert other sites of the trial to be on watch for similar adverse events “and then you proceed cautiously.”
He added that it’s “unfortunate” that an adverse reaction occurred at all, but said that putting the trial on hold and taking time to review the data is “one of the safety valves” that’s built into clinical trials.
“It’s not uncommon at all,” he said. He added that the adverse event could be unrelated to the vaccine and might have just occurred at the same time as the trial, “but you can’t presume that. You always make the presumption that it’s due directly to the actual vaccine or therapeutic.”
In a statement released Tuesday, AstraZeneca described the pause on its trial 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 company added that it is trying to expedite the review to “minimize any potential impact on the trial timeline.”
Former Food and Drug Administration Commissioner Dr. Scott Gottlieb, who sits on the board of competing vaccine developer Pfizer, said the pause on AstraZeneca’s trial is evidence that “the system works.”
“This is how the clinical trial process works and it worked here,” he said on CNBC’s “Squawk Box.” “I think we should never have had a doubt that the monitoring system that’s in place for clinical trials of this magnitude is independent and works.”
He added that AstraZeneca’s phase three trial is made up of about 10,000 participants, which is about a third of the size of other companies’ late-stage trials.
“So one case of a rare adverse event that could be associated with the vaccine is going to cause concern among regulators,” he said, adding that regulators and independent data safety monitoring boards will likely now comb through the data for signs of similar adverse events that might have been missed initially. He added that the delay in AstraZeneca’s trial enrollment will likely last for “at least days and maybe a couple of weeks.”
AstraZeneca, which licensed the vaccine from scientists at the University of Oxford, launched its phase three trial last month. It is one of at least three companies with late-stage trials underway, along with Pfizer and Moderna.
A vaccine is seen by some as key to ending the pandemic and slowing the spread of the coronavirus, which has so far infected at least 27.6 million people around the world and killed at least 898,200 people, according to data compiled by Johns Hopkins University.
The United States has invested more than $10 billion in six companies that are developing potential vaccines in order to secure doses. In May, the U.S. announced it would pay AstraZeneca $1.2 billion for at least 300 million doses of its potential vaccine.
The announcement that AstraZeneca would pause its trial came just one day after nine companies that are developing potential coronavirus vaccines, including AstraZeneca, publicly pledged to prioritize safety and uphold rigorous scientific standards in the rush to bring a vaccine to market.
The companies pledged to “always make the safety and well-being of vaccinated individuals our top priority.”
Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer, genetic-testing start-up Tempus and biotech company Illumina. He also serves as co-chair of Norwegian Cruise Lines’ and Royal Caribbean’s “Healthy Sail Panel.”
Originally published on CNBC