In a letter published Friday, Pfizer CEO Albert Bourla laid out exactly when the company expects to have safety and efficacy data for the experimental coronavirus vaccine it’s developing with partner BioNTech, and when it will likely seek emergency clearance in the U.S. Bourla wrote that Pfizer may know that whether its vaccine is effective by the end of the month, but it won’t file for an emergency use authorization until it meets the Food and Drug Administration’s safety and manufacturing requirements as well. Assuming positive results, Pfizer expects to have that information and file an application in mid- to late-November.
Pfizer is the only coronavirus vaccine developer that might produce data from a large-scale efficacy trial before the U.S. presidential election, making the timing of its disclosures, and potential approval of its vaccine, a highly charged political issue. The letter is an unusual declaration for a drugmaker, aimed at convincing a skeptical public that Pfizer will follow strict scientific guidelines and won’t bow to political pressure.
The global demand for a safe and effective coronavirus vaccine hasn’t just led to heightened scrutiny of developers and their progress, but forced them to be unusually transparent about their work.
In the past month, for instance, multiple vaccine developers have released the guidelines for their Phase 3 clinical trials. Companies have also announced study pauses for safety reviews, which aren’t usually disclosed but are typical occurrences in vaccine trials and a sign of proper scientific protocol. These events are a sign of the enormous pressure each company faces to earn the trust of the public and prove that no corners are being cut.
No company is bearing the brunt of this pressure more than Pfizer, which will likely soon become the first coronavirus vaccine developer in the world to report interim results from a Phase 3 trial.
Pfizer has repeatedly said those results, which could show whether its vaccine can prevent COVID-19, could come before the end of the month. And that has led to concerns that the Trump administration may pressure the FDA to clear its vaccine before the U.S. presidential election — concerns that became elevated as the White House initially fought, but then relented, against the publication of FDA guidelines requiring any shot to have two months of safety data before the agency would consider an emergency application.
Amidst the controversy, Bourla has been unusually outspoken. Earlier this month, he acknowledged the political pressure at hand in a memo posted on LinkedIn, noting that “in this hyper-partisan year, there are some who would like us to move more quickly and others who argue for delay.” Bourla, then, said that Pfizer would stay out of the political fray and advance its shot “at the speed of science,” regardless of when results come.
The FDA has since published its vaccine approval guidelines, which made a pre-election authorization highly unlikely and a move President Donald Trump claimed, without evidence, was politically motivated. Yet with the highly anticipated reveal of Pfizer’s data fast approaching, Bourla has spoken out again, taking the unusual step of clearly spelling out what’s to come for Pfizer’s shot.
“To ensure public trust and clear up a great deal of confusion, I believe it is essential for the public to understand our estimated timelines,” he wrote in a letter to “the billions of people, millions of businesses and hundreds of governments around the world” awaiting an effective coronavirus vaccine.
Pfizer won’t file for an emergency approval until showing its shot can prevent COVID-19 in a majority of those vaccinated, can be properly manufactured at scale, and until the company has “robust safety data” from thousands of patients, Bourla wrote.
Interim efficacy data may come by the end of the month or later, depending on infection rates, and Pfizer expects to have its manufacturing information ready shortly afterwards. But given Pfizer’s current pace of enrollment, it won’t have the the safety results the FDA requires — two months of follow-up for half of the patients in the trial — until the third week of November. Those patients have to have received the second shot of Pfizer’s two-dose regimen, which comes three weeks after the first.
“So let me be clear, assuming positive data, Pfizer will apply for Emergency Authorization Use in the U.S. soon after the safety milestone is achieved,” Bourla wrote.
As of Monday, 37,864 of a planned 44,000 participants had been enrolled in Pfizer’s Phase 3 trial, and 31,062 of them had gotten their second shot.
