Pfizer passes COVID-19 vaccine safety milestone, reveals 95% efficacy ahead of EUA

Pfizer is preparing to file its COVID-19 vaccine for emergency use authorization (EUA) after passing a key safety milestone. CEO Albert Bourla, Ph.D., said Pfizer now has the median two-month follow-up data needed to secure EUA from the FDA, putting it a step closer to bringing its vaccine to market in the U.S.

Talking at virtual events hosted by The New York Times and Stat, Bourla said Pfizer is preparing to seek EUA for the vaccine, which it developed with BioNTech, using the safety data and the efficacy results it gave a glimpse of last week. Exactly when Pfizer will seek EUA from the FDA is unknown, with Bourla opting against making a statement that would create expectations.

Pfizer also initially held off on providing a more detailed look at the efficacy data as it expected the effectiveness figure to change as more participants developed COVID-19. The detailed data arrived Wednesday when the Big Pharma revealed its vaccine was 95% effective in the phase 3 trial.

In the placebo arm, 162 participants developed COVID-19, compared to eight subjects in the vaccine group. There were nine severe cases of COVID-19 in the placebo arm and one in the vaccine group. Importantly, Pfizer said the efficacy in people aged 65 years and older was 94%. It will take more time for the key question of vaccine durability to be answered, though.

The efficacy data are similar to those reported by Moderna, but, with the caveat that cross-trial comparisons can be unreliable, other results suggest Pfizer may have an edge in terms of tolerability. Pfizer and BioNTech, which picked BNT162b2 as their phase 3 asset on the basis of its tolerability, said the only grade 3 solicited adverse events to affect more than 2% of people after either the first or second dose were fatigue, 3.8%, and headache, 2%.

After the second dose of Moderna’s vaccine, 9.7% of subjects reported grade 3 fatigue. Between 2% and 8.9% of subjects reported either grade 3 muscle pain, joint pain, headache, pain or redness at the injection site.

Pfizer looks set to be the first company to seek EUA, with Moderna following closely behind. The Big Pharma took the lead after Bourla told his researchers to accelerate their timeline, which initially targeted a mid-2021 launch. Bourla wanted a vaccine ready ahead of a possible winter surge in cases of COVID-19.

With Pfizer aiming to ship 50 million doses globally this year, the vaccine may ultimately play a small role in helping the U.S. and other countries through the winter, but the accelerated timeline will still likely save lives. Bourla credits his decision not to take U.S. government money, and thereby avoid saddling Pfizer with bureaucracy that may have gone along with it, as a factor in Pfizer’s progress.

Bourla said he “knew this would become very political.” Even though Pfizer used its own money, it has still been caught up in the political side of the COVID-19 vaccine race, with President Donald Trump accusing the company of holding off on sharing data until after the election. Bourla rejected the accusation that Pfizer conspired with the FDA to delay the readout. 

“I will be very direct. We didn’t conspire with anyone of course. The election for us was always an artificial deadline. It may have been very important for the President but not for us,” Bourla said.