AstraZeneca’s vaccine prospects were looking up Monday when the company reported solid results from a new phase 3 trial it needed to win U.S. approval. Then, sometime after midnight, U.S. officials took the rare step of publicly questioning whether those data were actually complete.
Less than 24 hours after the British drugmaker touted 79% efficacy against symptomatic COVID-19 and 100% efficacy against severe disease in an interim analysis—providing only sketchy details about the numbers in a call with reporters—the trial’s independent Data and Safety Monitoring Board (DSMB) raised a red flag to U.S. officials.
“AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data,” the National Institute of Allergy and Infectious Diseases (NIAID) said in a statement overnight.
Also in that statement, NIAID said it had urged AstraZeneca to round up any missing data and publish up-to-date numbers “as quickly as possible.” In the hours that followed the NIAID statement, a PR crisis began developing for AZ and its vaccine.
AstraZeneca said Tuesday morning that the published numbers were based on an interim analysis with a data cutoff of Feb. 17. The company is now conducting its review of the trial’s primary analysis.
“We will immediately engage with the independent data safety monitoring board to share our primary analysis with the most up to date efficacy data,” AstraZeneca said. “We intend to issue results of the primary analysis within 48 hours.”
In meetings during February and March, the data board reviewed evidence suggesting the vaccine was 69% to 74% effective, The Washington Post reports, citing the DSMB's letter. The DSMB "strongly recommended" that the company share the info with the public. One DSMB member told the newspaper AZ's move was like "telling your mother you got an A in a course, when you got an A in the first quiz but a C in the overall course."
The back-and-forth on the phase 3 data is only AstraZeneca's latest stumble in its development and rollout of the University of Oxford-partnered vaccine. Other missteps include a dosing error in a prior phase 3 trial that forced the new study, plus supply shortfalls that have angered EU officials. In Europe, the vaccine's rollout has run into safety concerns, but regulators recently offered a fresh endorsement of the shot's safety and efficacy profile.
During Monday’s data release, AstraZeneca executives weren’t forthcoming with information about case numbers in a call with reporters. The company never disclosed the breakdown among cases in the placebo and vaccine arms, and reporters asked several times for more information before the executives divulged numbers about severe cases.
Finally, AZ execs acknowledged there had been five severe cases in the placebo group and none in the vaccine group. But that info was outdated, executive vice president of biopharma R&D Mene Pangalos cautioned.
In the large, 32,000-plus participant trial, investigators tracked 141 total cases of symptomatic COVID-19. AZ didn’t say how many of those cases cropped up in the placebo group versus the vaccine recipients. With the data, AstraZeneca said it would seek a U.S. emergency use authorization in the first half of April.
In addition to the pair of statements from NIAID and AstraZeneca, President Joe Biden's chief medical adviser Anthony Fauci, M.D., weighed in early Tuesday. He told "Good Morning America" the AZ vaccine is likely "very good" but that the data board was concerned about "somewhat outdated" information touted by the company. The board wrote a "rather harsh note" to the company and copied Fauci on its letter, he said on the program. The situation was the result of an "unforced error" on AZ's part, Fauci said.
Meanwhile, the vaccine is already licensed in more than 70 countries, and AZ continues to work to increase production and meet delivery targets. Earlier this month, the company cut its European delivery target to 100 million doses in the first half of 2021, down from a prior target of 300 million doses.
The company has said it could have 30 million doses ready for immediate delivery upon a U.S. authorization.