The submission comes day after BNT162b2 became the first fully approved COVID-19 vaccine by the FDA.
Pfizer-BioNTech have begun the process of seeking US Food and Drug Administration (FDA) regulation for a COVID-19 vaccine booster dose.
The companies announced Wednesday they are initiating a rolling submission for COVID-19 vaccine BNT162b2 (Comirnaty) to seek an FDA supplemental Biologics License Application (sBLA) that would allow for marketing and prescribing of a third booster dose of the vaccine for fully vaccinated individuals aged 16 years and older.
The sBLA pursuit comes only 2 days after the collaborating pharmaceutical companies received BLA approval for BNT162b2—the very first COVID-19 vaccine given full approval by the FDA. The submission for the supplemental indication is anticipated to be completed by the end of this week, and will include phase 3 clinical trial data involving 306 participants who received a third dose of the mRNA COVID-19 vaccine.
According to Pfizer, their trial population was between the ages of 18-55 years and had received their third BNT162b2 dose between 4.8 and 8 months following completion of the initial 2-dose regimen. Investigators of the to-be-published phase 3 data reported “robust neutralizing antibodies” elicited by the booster vaccine dose in participants who were without evidence of SARS-CoV-2 infection, after 1 month.
Investigators additionally reported a 3.3-fold greater count of SARS-CoV-2 50% neutralizing titers after the third dose than was observed after the second dose of BNT162b2; the post-booster neutralizing titer count met the study’s prespecified 1.5-fold non-inferiority criterion to achieve statistical superiority.
The booster dose additionally provided a 4-fold response to a greater rate of treated participants (99.5%) than that observed after the second dose (98.0%).
Regarding safety, the booster dose’s reactogenicity profile ≤7 days after administration was “typically mild to moderate,” according to Pfizer, with an adverse event profile that was generally consistent with previously observed BNT162b2 clinical data. The most common events among participants to receive a booster dose included injection site pain, fatigue, headache, muscle and joint pain, and chills.
Though data has begun to support the utility of COVID-19 vaccine booster doses in a population with concerns of waning immunity amid major outbreaks of the doubly-transmissible Delta variant, their necessity has been debated by experts.
The FDA granted Emergency Use Authorization (EUA) to both Pfizer-BioNTech and Moderna for their mRNA vaccines to be administered as booter doses for severely immunocompromised patients just last week, on the basis of clinical evidence showing a weakened immune response in vaccinated persons treated for cancer or organ transplant recipients, among others.
Days later, a report stated the Biden administration would begin advocating for booster doses at 8 months following their final dose for all Americans, as well as FDA authorization of booster doses for all adults by mid-September.
Carlos del Rio, MD, Executive Associate Dean of Emory School of Medicine & Grady Health System, told Contagion® that more substantial data on waning vaccination immunity is warranted, as much of what’s been discussed has been laboratory data.
“I want to see clinical outcomes data,” del Rio said. “And while we’re seeing breakthroughs, I want to see those by date of vaccination.”
While much discussion around the threat of breakthrough infection among early vaccinated persons has hinged on the issues occurring in Israel, del Rio stressed the significance of data coming from similarly vaccinated countries like Iceland, of which 71.5% of the population is fully vaccinated as of Wednesday.
“They’re seeing breakthroughs, they’re seeing cases, but they’re still not seeing hospitalizations and deaths,” del Rio said. “And I think that’s something we also need to realize—we’re going to have to learn that our goal should not be eradication of this virus, it should be vaccination to achieve decrease impact of this virus.”
As of Wednesday, 52.2% of the US population was fully vaccinated against COVID-19. The 7-day average of new COVID-19 cases was 151,441.