Questions For The FDA

BritishMedicalJournal |   With the US awash in news about rising cases of the Delta variant, including among the “fully vaccinated,” the vaccine’s efficacy profile is in question. But some medical commentators are delivering an upbeat message. Former FDA commissioner Scott Gottlieb, who is on Pfizer’s board, said: “Remember, the original premise behind these vaccines were [sic] that they would substantially reduce the risk of death and severe disease and hospitalization. And that was the data that came out of the initial clinical trials.”

Yet, the trials were not designed to study severe disease. In the data that supported Pfizer’s EUA, the company itself characterized the “severe covid-19” endpoint results as “preliminary evidence.” Hospital admission numbers were not reported, and zero covid-19 deaths occurred.

In the preprint, high efficacy against “severe covid-19” is reported based on all follow-up time (one event in the vaccinated group vs 30 in placebo), but the number of hospital admissions is not reported so we don’t know which, if any, of these patients were ill enough to require hospital treatment. (In Moderna’s trial, data last year showed that 21 of 30 “severe covid-19” cases were not admitted to hospital; Table S14).

And on preventing death from covid-19, there are too few data to draw conclusions—a total of three covid-19 related deaths (one on vaccine, two on placebo). There were 29 total deaths during blinded follow-up (15 in the vaccine arm; 14 in placebo).

The crucial question, however, is whether the waning efficacy seen in the primary endpoint data also applies to the vaccine’s efficacy against severe disease. Unfortunately, Pfizer’s new preprint does not report the results in a way that allows for evaluating this question.

Approval imminent without data transparency, or even an advisory committee meeting?

Last December, with limited data, the FDA granted Pfizer’s vaccine an EUA, enabling access to all Americans who wanted one. It sent a clear message that the FDA could both address the enormous demand for vaccines without compromising on the science. A “full approval” could remain a high bar.

But here we are, with FDA reportedly on the verge of granting a marketing license 13 months into the still ongoing, two year pivotal trial, with no reported data past 13 March 2021, unclear efficacy after six months due to unblinding, evidence of waning protection irrespective of the Delta variant, and limited reporting of safety data. (The preprint reports “decreased appetite, lethargy, asthenia, malaise, night sweats, and hyperhidrosis were new adverse events attributable to BNT162b2 not previously identified in earlier reports,” but provides no data tables showing the frequency of these, or other, adverse events.)

It’s not helping matters that FDA now says it won’t convene its advisory committee to discuss the data ahead of approving Pfizer’s vaccine. (Last August, to address vaccine hesitancy, the agency had “committed to use an advisory committee composed of independent experts to ensure deliberations about authorization or licensure are transparent for the public.”)

Prior to the preprint, my view, along with a group of around 30 clinicians, scientists, and patient advocates, was that there were simply too many open questions about all covid-19 vaccines to support approving any this year. The preprint has, unfortunately, addressed very few of those open questions, and has raised some new ones.

I reiterate our call: “slow down and get the science right—there is no legitimate reason to hurry to grant a license to a coronavirus vaccine.”

FDA should be demanding that the companies complete the two year follow-up, as originally planned (even without a placebo group, much can still be learned about safety). They should demand adequate, controlled studies using patient outcomes in the now substantial population of people who have recovered from covid. And regulators should bolster public trust by helping ensure that everyone can access the underlying data.

Peter Doshi, senior editor, The BMJ.

Competing interests: I helped organize the Coalition Advocating for Adequately Licensed Medicines (CAALM), which has formally petitioned the FDA to refrain from fully approving any covid-19 vaccine this year (docket FDA-2021-P-0786). A full list of competing interests is available here.