Pfizer Analyst Breaks Down The FDA Process For Coronavirus Vaccine Candidate

Pfizer Inc. PFE and BioNTech SE's – ADR BNTX coronavirus vaccine candidate passed the Adcom test, with the FDA panel voting 17-4 in favor of its risk-benefit profile in individuals 16 and older. 

Here's SVB Leerink analyst Geoffrey Porges' take on the dynamics of the Adcom vote. 

FDA Approval Imminent: The 17-4 vote favoring the vaccine candidate, with one abstention, should support emergency use authorization within days, Porges said in a note. 

"It is possible that the 16-17-year-old cohort is excluded from the initial EUA, which practically won't make much difference anyway, given the tiering of access proposed by the CDC's ACIP," the analyst said.

The Panel's Concerns: The vaccine committee expressed concerns regarding the trial integrity after a potential emergency use authorization, as well as long-term follow-up on trial participants and safety, especially against the backdrop of anaphylaxis reported from the U.K. following vaccination, Porges said.

The members debated whether the 16-17 age group should be included in an emergency use authorization, the analyst said. 

The most important reason for the "no" and "abstain" votes is the inclusion of the 16-17-year olds, he said. 

"Had the voting question excluded this cohort, the vote in favor of approval may have been unanimous."

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The committee voiced concerns regarding the loss of blinded follow-up and randomized data when a vaccine becomes available under emergency use, Porges said.

Some members were worried about the impact of unblinding on data, which is required for the full Biologics License Application, the analyst said. 

The FDA proposed an alternative: a "blinded crossover' design, in which participants in the active vaccine arm will receive placebo shots, while placebo participants will receive active vaccine without unblinding, he said. 

Pfizer highlighted the logistical difficulties associated with this "blinded crossover" design, which would require bringing the 44,000 trial participants back to the trial sites two additional times for vaccination.

The FDA suggested other approaches may be utilized to assess long-term safety after unblinding, Porges said.

One potential way to assess the durability of response would be to compare the number of COVID-19 cases seen in the newly vaccinated individuals versus previously vaccinated individuals, the analyst said. 

The safety concerns centered around anaphylaxis and pregnant women, according to SVB Leerink.

The FDA said they already include warning language in the prescribing information, and will finalize the language in the following days, Porges said. 

On the potential impact of vaccination on pregnant women, Pfizer said it is conducting a pre-clinical study in rats which should report data later this month, the analyst said.

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