The FDA has released its internal review documents ahead of the closely watched COVID-19 vaccine advisory committee meeting scheduled for Thursday—and they bode well for Pfizer and partner BioNTech's prospects for securing a quick emergency use authorization (EUA).
The FDA meeting briefing, published (PDF) on Tuesday, confirmed the efficacy and safety profile of Pfizer and BioNTech’s BNT162b2, reiterating that the shot was 95% effective at preventing COVID-19 after two doses with no serious safety concerns.
At its per-protocol 2-dose regimen, the Pfizer-BioNTech vaccine was "highly effective" in preventing COVID-19 occurring at least 7 days after completion of vaccination, the FDA reviewers said in the document.
Statistical analysis suggests the vaccine’s true efficacy is at least 90.3% with the probability hitting 97.5%. Notably, the efficacy was consistently high at 94.7% for participants at 65 years of age or older. And even in those with underlying conditions who are considered at risk of developing serious COVID-19 cases, the vaccine’s efficacy stood strong at 95.3%.
Similar protection levels that mostly hovered above 93% were also observed across sex and racial/ethnic groups. In all, one case of severe COVID-19 occurred in the vaccine group, while the placebo group recorded nine cases at the data cutoff.
The FDA reviewers also noticed an early onset of protection after the first dose of vaccination. COVID-19 cases for the BNT162b2 and placebo groups were tracking together until about 14 days after the first dose. After that, cases in the Pfizer/BioNTech shot's study arm reached a plateau, whereas the numbers in the placebo arm continued upward. But the reviewers cautioned against the one-dose idea, noting that the trial didn't have a single-dose arm for that analysis.
Aside from efficacy, safety is a key focus of the public’s attention on COVID-19 vaccines—especially for the brand-new mRNA technology on which BNT162b2 is based. And the need for robust safety data, as required by the FDA, has previously also been highlighted by Pfizer CEO Albert Bourla, Ph.D.
Immediate manifestation of an inflammatory response to vaccination was mostly mild to moderate and short-lived for BNT162b2 in its pivotal trial. Serious side effects were infrequent at below 1% between the BNT162b2 and placebo groups, though the incidence of any side effect was much higher for the vaccine group.
As part of its EUA application, Pfizer and BioNTech included a plan for safety surveillance that will monitor reports of serious side effects.
In a Tuesday note to clients, Jefferies analyst Michael Yee called the documents "very simple and straightforward which we think will lead to approval imminently." JPMorgan analyst Cory Kasimov, for his part, called the reviewers' assessment "a surprise to no one" in his own note to clients.
BNT162b2 has already earned its first global authorization, snagging a go-ahead from the U.K. last week.
Editor's Note: The story has made several corrections that removed a few quotes that were previously mistakenly attributed to FDA reviewers.