US health officials raised concerns on Tuesday that positive results that AstraZeneca announced Monday for its Covid-19 vaccine may have been based on “an incomplete view of the efficacy data ”of a clinical trial and was based on“ outdated information ”, casting another curve in the company’s vaccine saga.
In a statement issued just after midnight on Tuesday morning, the National Institute of Allergy and Infectious Diseases said it was informed of data issues by the data and safety monitoring board that audited the trial. DSMBs consist of independent medical experts who provide an extra screen of data produced from clinical trials.
“We urge the company to work with the DSMB to review effectiveness data and ensure that the most accurate and up-to-date effectiveness data is made public as soon as possible,” said NIAID.
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In an interview on Tuesday morning with STAT, Anthony Fauci, head of NIAID, said that the DSMB raised concerns because he felt the results in an AstraZeneca press release on Monday seemed more favorable than the most recent data. recent studies of the vaccine have shown.
“I was a little stunned,” said Fauci. “The data security and monitoring board was concerned that the data included in AZ’s press release was not the most accurate and up-to-date. This is what the DSMB communicated to AZ in a very severe way. Having seen that letter, we couldn’t just leave it unanswered. “
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Asked why NIAID released its unusual statement, Fauci said: “We felt that we could not be silent. Because if we were to remain silent, we could be accused of covering up something. And we definitely didn’t want to be in that position. “
He added: “In my opinion, it is an unforced error by the company.”
The results released on Monday by AstraZeneca came from an interim analysis of a test of 32,000 volunteers until February 17. In a statement on Tuesday, the company said it would “immediately get involved” with the DSMB “to share our primary analysis with the most up-to-date efficacy data.” The company said it plans to announce the results of the primary analysis within 48 hours. hours.
“We reviewed the preliminary assessment of the primary analysis and the results were consistent with the intermediate analysis,” said the company. “We are now completing the validation of the statistical analysis.”
The NIAID two-paragraph statement opened yet another chapter on the road to the AstraZeneca vaccine, which was developed in conjunction with researchers at the University of Oxford. It didn’t even happen 24 hours after the company announced in a press release on Monday that its vaccine was 79% effective in preventing symptomatic Covid-19 in a test in the United States, a result that was better than expected with based on previous tests and appeared to help resolve some questions about the vaccine’s robustness. The company also said that immunization reduced severe Covid-19 and hospitalization by 100%.
The results were seen as a final step before the company asked US regulators for authorization to take it, which is already approved in other countries.
The company’s vaccine was under scrutiny more recently, after European countries stopped its launch last week for safety reasons linked to blood clots, but the European Medicines Agency later said the vaccine’s benefits outweighed its risks and the campaigns were restarted.
Based on the trial data released on Monday, AstraZeneca said the study did not identify any new safety concerns. A specific review found no risk of blood clots. The study also did not detect a specific type of clot in blood vessels near the brain that EMA said may be associated with the vaccine. However, this type of clot, called cerebral venous sinus thrombosis, is so rare that it cannot be expected to occur even in a large clinical trial.
NIAID’s statement on Tuesday cited only the DSMB’s concerns about effectiveness data and did not mention security issues.
The two-dose AstraZeneca vaccine is seen as a great hope to help expand access to the vaccine worldwide because it is cheaper than other Covid-19 vaccines and easier to manufacture and distribute than some others. It is being used widely in Europe and increasingly in Asia.
But the company’s vaccination efforts were hampered by setbacks and questions about its public announcements. In the beginning, the US study was stopped for a month and a half because of a brain hemorrhage in a patient that was later determined to be unrelated to the vaccine. In the initial test results announced earlier, the data seemed to suggest at one point that the second dose of the vaccine decreased its effectiveness. Some of previous confusion arose of the company’s unusual strategy of gathering data from clinical trials in its analyzes.
The ups and downs with AstraZeneca’s vaccines have raised concerns that the public may turn away from an immunization that could help tame the Covid-19 pandemic, at a time when public health officials are asking people to get vaccinated when they get a chance. Fauci said in “Good Morning America” Tuesday that the frustration was that “this is most likely a very good vaccine” and that he hoped people would understand that the concerns of the DSMB were an example of one of the many barriers that guarantee quality of the vaccine development process.
“If you look at them, the data is really very good, but when they put it in the press release, it was not entirely accurate,” said Fauci. “We essentially have to keep trying as hard as we can to make people understand that there are safeguards in place.”
Asked whether he was concerned about people’s confidence in the AstraZeneca vaccine and others, Fauci told STAT: “Obviously, whenever something like this happens, it can undermine public confidence.”
But he stressed that the FDA, when reviewing the AstraZeneca vaccine for authorization, will make an independent decision.
Helen Branswell and Matthew Herper contributed to the report.
This story has been updated with comments from AstraZeneca and Anthony Fauci.