Comirnaty booster gets adcomm thumbs up, for limited population

Regulatory NewsRegulatory News | 17 September 2021 |  By 

An advisory committee to the US Food and Drug Administration (FDA) voted 16-2 on Friday against approval of a third booster dose added on to the 2-dose regimen for Pfizer’s COVID-19 vaccine Comirnaty. However, the committee voted unanimously in favor of an emergency use authorization (EUA) for booster doses for those aged 65 years and up, as well as health care workers and other individuals at high risk for COVID-19 because of occupational exposure.
The ball is now in FDA’s court. Peter Marks, head of FDA’s Center for Biologics Evaluation and Research, reminded committee members toward the end of the day-long meeting of the Vaccines and Related Biologic Products advisory committee (VRBPAC) that FDA need not follow the recommendations of its advisory committees -- although it usually does.
Marks, who gave introductory remarks when the meeting kicked off Friday morning, reappeared before the first voting question was put to the committee. As he had signaled he would earlier in the week at RAPS Convergence 2021, Marks pointed to observational data from Israel showing the Pfizer vaccine’s waning efficacy in the face of the Delta variant of SARS-CoV-2. (RELATED: Marks defends push toward COVID vaccine boosters, Regulatory Focus 13 September 2021)
Though the committee was initially presented with just one voting question, it was agreed before the vote that a new, more restrictive voting question could be formulated if the committee should vote against a supplemental biologics license application (sBLA) for boosters for individuals aged 16 and up.
Committee members, largely unpersuaded that the data presented by Pfizer and the Israeli Ministry of Health gave adequate assurance of safety and effectiveness of a booster, voted 16-2 against the first voting question. Focus reviewed the briefing documents from both Pfizer and FDA and highlighted key arguments and critiques when they became available Wednesday. (RELATED: In advance of adcomm, Pfizer makes its case for Comirnaty booster, Regulatory Focus 15 September 2021).
In addition to concerns that sample sizes were not large enough in randomized controlled trial data on boosters, VRBPAC members also expressed concern that data were not mature and that teasing out how waning efficacy contributes to breakthrough COVID-19 infections is difficult. 2021 has seen the rise of the Delta COVID-19 variant, which is both more transmissible and more likely to cause breakthrough infections; this turn of events greatly complicates population-level data analysis.
Further, approving a booster for younger adults at this juncture seemed problematic to many on the committee, considering the signal for increased risk of myocarditis and pericarditis in younger males after their second dose of the Pfizer primary series.
Marks and VRBPAC acting chair, the University of Michigan’s Arnold Monto, discussed wording for the question that would be put to the committee in the second round. After a 10-minute break, the committee was next asked whether, taking into account the totality of the evidence available, the benefits outweighed risks for administering a third Comirnaty dose, 6 months after the 2-dose primary series, for individuals aged 65 years and up and those at high risk of severe COVID-19.
This time, the vote was unanimous, with 18 in favor of issuing what had now become an emergency use authorization.
In response to concerns voiced by many committee members, the committee logged a unanimous “yes” response to a later “poll” — not a voting question — that clarified that health care workers and others at high risk of occupational exposure to COVID-19 should also be booster-eligible.
“This is really an amazing vote,” said Amanda Cohn, chief medical officer of the National Center for Immunizations and Respiratory Diseases (NCIRD) at the Centers for Disease Control and Prevention (CDC). Cohn, who also serves as the designated federal officer to CDC’s vaccines advisory committee, noted that this third dose will serve to protect the vaccinated population who are likely most at risk of COVID-19 infection.
Speaking of older adults and health care workers, Cohn said, “These are the groups who got vaccinated last December and January and February, so these are the groups who are really 6 months out” from completing their vaccine series.
CDC’s Advisory Committee on Immunization Practices (ACIP) is due to meet next week and may consider making booster administration recommendations, if FDA has issued an EUA or approval for a booster dose by that time.
VRBPAC briefing materials and web links


© 2022 Regulatory Affairs Professionals Society.

Discover more of what matters to you