Chief executive Albert Bourla wrote in the letter that while the company projects it may have effectiveness data in October, there will not be sufficient safety data to satisfy criteria laid out by the Food and Drug Administration until late November.
“A key point that I’d like to make clear is that effectiveness would satisfy only one of the three requirements and, alone, would not be enough for us to apply for approval for public use,” Bourla said. “Safety is, and will remain, our number one priority.”
The letter was welcomed by Eric Topol, a physician-scientist at Scripps Research Translational Institute who joined other experts in sending a letter to Bourla in late September, asking the company not to seek authorization for a vaccine before late November. Topol recently had a virtual meeting with company executives to express his concerns and said he was frustrated they would not answer directly when he asked if they would seek broader use of a vaccine before Nov. 3.
Bourla’s emphasis on having data in October “is what got many of us concerned, whether it was inadvertently playing into the political pressure or just because the incentives were aligned,” Topol said. “I thought [the letter] was very good. I wish it had been done potentially even earlier.”
The FDA in October issued guidance explaining the criteria for an emergency use authorization, which will hold a vaccine given to healthy people to a higher standard than the typically low threshold that a medical product “may be effective” for emergency use. The agency put forth a requirement — despite White House objections — that vaccine candidates must have a minimum of two months of follow-up data on half of the participants in the study.
Pfizer will not have such data until the third week of November. Moderna, a biotechnology company, will not have enough safety data to apply for regulatory authorization until two days before Thanksgiving, according to spokesman Ray Jordan. Two other late-stage vaccine trials, from AstraZeneca and Johnson & Johnson, are paused because of potential safety concerns.