Federal health officials said early Tuesday that results from a U.S. trial of AstraZeneca’s Covid-19 vaccine may have relied on “outdated information” that “may have provided an incomplete view of the efficacy data,” casting doubt on an announcement on Monday that had been seen as good news for the British-Swedish company as well as the global vaccination drive.
In a highly unusual statement released after midnight, the National Institute of Allergy and Infectious Diseases said that the data and safety monitoring board, an independent panel of medical experts under the National Institutes of Health that has been helping to oversee AstraZeneca’s U.S. trial, had notified government agencies and AstraZeneca late Monday that it was “concerned” by information the company had released that morning.
The institute urged AstraZeneca to work with the monitoring board “to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”
In a statement released Tuesday morning, AstraZeneca said the interim results it announced on Monday were current as of Feb. 17. The company said that a preliminary review had found its primary analysis — the more up-to-date results that will be scrutinized by the Food and Drug Administration — to be “consistent” with the interim analysis.
The company said it would immediately share its most up-to-date efficacy data with the monitoring board and plans to issue results from the primary analysis within 48 hours.
In a news release on Monday announcing the results of the U.S. trial, the company said that the vaccine it developed with the University of Oxford was 79 percent effective against Covid-19, a higher figure than observed in previous trials, and completely prevented the worst outcomes from the disease. The long-anticipated results were seen as encouraging global confidence in the vaccine, which was shaken this month when more than a dozen countries, mostly in Europe, temporarily suspended the shot’s use over concerns about possible rare side effects. After conducting a review, Europe’s top drug regulator said last week that the shot was “safe and effective.”
Companies sponsoring drug or vaccine trials typically wait for the monitoring board to review analyses and conclude that the study has yielded an answer before they announce trial results. In recent days, the monitoring board’s analysis of the AstraZeneca trial was delayed several times because the board had to ask for revised reports from those handling trial data on behalf of the company, according to a person familiar with the matter who was not authorized to discuss it publicly. The monitoring board ultimately conveyed the results of the study to AstraZeneca in a meeting over the weekend, leading to the company’s announcement Monday morning.
Dr. Eric Topol, a clinical trials expert at Scripps Research in San Diego, said it was “highly irregular” to see such a public display of friction between a monitoring board and a study sponsor, which are typically in close concordance.
“I’ve never seen anything like this,” he said in an interview after the institute’s statement was released. “It’s so, so troubling.”