Tracking today’s FDA advisory panel meeting on the Pfizer/BioNTech Covid-19 vaccine

A panel of outside experts is meeting Thursday to consider whether the Food and Drug Administration ought to give an emergency use authorization to the Covid-19 vaccine being developed by Pfizer and BioNTech, a vaccine that appeared to be highly efficacious in a Phase 3 clinical trial.

Earlier this week, the United Kingdom started using the vaccine, which is currently known by the working name BNT162b2. On Wednesday, Canada’s drug regulator announced it had approved emergency use of the vaccine.

The U.S. begins its process with Thursday’s meeting of the Vaccines and Related Biological Products Advisory Committee, or VRBPAC. If the panel recommends the issuance of an EUA, and if the FDA follows the advice, the rollout of Covid-19 vaccine will begin within a few days in the United States.

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It’s widely assumed VRBPAC will vote to recommend the vaccine and the FDA will issue the EUA; in a report to the panel published online on Tuesday, the FDA’s scientists endorsed the vaccine’s safety and efficacy.

But that doesn’t mean questions won’t be asked and concerns won’t be raised during the day-long meeting. (Draft agenda found here.)  VRBPAC members come to a meeting ready to kick tires hard on behalf of the American public.

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Our live coverage of the meeting is below. We’ll be posting updates and analysis throughout the day, in reverse chronological order.

Some news on vaccination during pregnancy or lactation

1:55 p.m.: As Covid-19 vaccine rollout nears, a key question has been: Should pregnant and lactating people be vaccinated? There are no data on which to base an answer, but some may be on the way.

The FDA told vaccine manufacturers they had to do what are called DART studies — that’s short for developmental and reproductive toxicity studies — before they could conduct clinical trials to test if these vaccines are safe to use in pregnancy and during breastfeeding. DART studies are done in animals, looking to see if there are any signs a vaccine might hurt a developing fetus or pose a threat to the pregnancy.

None of the vaccine manufacturers near the front of the vaccine pipeline has completed DART studies. But on Thursday, Pfizer told the VRBPAC meeting it expects preliminary results from its DART studies in Wistar rats by mid-December — in other words, within days.

The company will still have to do trials in people who are pregnant and lactating before the FDA would agree to specifically authorize the vaccine for these populations. But experts on the issue of drug and vaccine testing during pregnancy have urged the agency not to close the door to use in these groups in the meantime. In an opinion piece published Wednesday in STAT, they argued that the FDA should allow the vaccine to be offered to pregnant and lactating people, and let them decide whether they want to be vaccinated.

Vaccination in the United States could begin within days, and health care workers are at the front of the line. About 75% of health care workers are women and a large portion of them are of child-bearing age. The CDC estimates that at any given time, about 330,000 health care workers are either pregnant or lactating.

— Helen Branswell

Public hearing elevates vaccine hesitancy issue

1:45 pm: Vaccine hesitancy was on full display during the one-hour open public hearing, as multiple speakers raised concerns about the safety of the Pfizer/BioNTech vaccine and the legitimacy of granting early authorization based on limited data.

The skeptical comments, some of which veered uncomfortably close to dangerous conspiracy theories, underscore the challenge facing vaccine makers and public health officials in convincing Americans to get vaccinated against Covid-19.

One speaker, who described herself as a mother of a child who she said was “injured” by routine childhood vaccinations, urged the FDA to disclose all the ingredients that go into the Covid vaccine, including “aborted fetal cells” — a false claim.

Another speaker, a pediatrician from Florida who said he does not require his patients to get routine vaccines, highlighted potential safety risks that some people might experience if they get vaccinated.

Several other speakers voiced concerns that the clinical trial conducted by Pfizer and BioNTech was rushed, or that certain participant groups, particularly people of color, were underrepresented in the clinical database. The 44,000-patient clinical trial enrolled a diverse patient population in terms of race and ethnicity, age, and underlying health conditions. About 26% of participants were identified as Latino and 10% as Black, with the study evenly split between men and women.

To be clear, these panels are not meant to be coronations of clinical data without anyone asking appropriately probing questions. But these days, distinguishing healthy skepticism from damaging anti-vaccine tropes is increasingly difficult. The FDA wants to encourage transparency in the review process to enhance vaccine confidence, but by doing so, it also opens up the possibility of amplifying people with the opposite agenda.

Sidney Wolfe, founder and senior advisor of Public Citizen’s Health Research Group, gave testimony during the open public hearing, expressing his support for the emergency use authorization of the Pfizer/BioNTech Covid vaccine. Wolfe is notorious for opposing almost every new drug that comes in front of the FDA, so his support shows that even perma-skeptics can be convinced that vaccine makers are doing something right.

— Adam Feuerstein

Trying to solve a sticky wicket

12:15 p.m.: The morning’s session concluded with a fascinating presentation on a really tricky topic.

A major dilemma facing the FDA has been the question of whether participants in the placebo arms of vaccine trials ought to be offered vaccine when an EUA is issued.

Some of the manufacturers — notably Pfizer — want to give their placebo recipients vaccine. The FDA wants the trials to generate as much placebo-controlled data for as long as possible, because once the placebo groups are unblinded and vaccinated, important opportunities to collect data are lost forever.

The VRBPAC panel heard an interesting compromise proposal at the end of the morning session from Steven Goodman, associate dean of clinical and translational research at the Stanford University School of Medicine.

Goodman said ethically, the companies are not required to vaccinate the people in their placebo arms, though from a practical point of view, they could lose participants anyway when people in the trial become eligible to be vaccinated. And he said that vaccinating all placebo recipients after the issuance of an EUA would allow trial volunteers to “jump the queue” — get vaccinated before other people of their age or risk group.

The proposed compromise would be to vaccinate placebo recipients, but maintain the blinding. What that would mean would be that when people in a trial were eligible to get vaccine where they lived, they would be vaccinated. If someone had received placebo shots originally, they’d be given vaccine. If someone had received vaccine doses, they’d get placebo shots. They would not be told what their original status was — but all would be confident that they had received vaccine.

“As soon as they can get it outside their trial than this would kick in,” Goodman said. “I don’t think we have that special obligation to give them the vaccine early.”

This approach would remove the motivation for people who are in trials to withdraw as vaccine starts to roll out across the country, he said. And while vaccinating the placebo arm would result in some loss of data — for instance, the ability to continue to compare safety data long term — it would allow the trials to continue to gather comparative data on issues like the durability of the immune response generated by the vaccine.

On the question of whether placebo-controlled vaccine trials can continue once one vaccine has received an EUA, Goodman said in times of limited vaccine supplies it would still be ethical, but might become increasingly infeasible as supplies increase and more and more people have access to vaccines.

— Helen Branswell

How do you monitor a vaccine’s safety and efficacy after it is authorized?

11 a.m.: The big question when a vaccine is tested in 30,000 people and then given to 30 (or 300?) million is how one knows if it is as safe and effective as it initially appeared.

Part of the answer is to conduct more clinical trials, but it’s also necessary to conduct observational studies that can capture how well the vaccine is working in the real world. The plans for doing this were presented by Nancy Messonnier of the Centers for Disease Control and Prevention, who became well known for her prescient public remarks early in the pandemic.

On safety: the CDC is stitching together a number of large databases that will allow it to track adverse events and try to determine if those are side effects of the vaccine. These include the Vaccine Adverse Events Reporting System, run by the CDC and the FDA, but also other databases including the CDC’s V-safe and VSD databases, and databases from the Department of Veterans Affairs, Department of Defense, and Genesis Healthcare, a database in long-term care facilities run with Brown University.

And how do you track efficacy without a clinical trial? That will be done in much the same way that the efficacy of flu vaccines is tracked, by comparing whether people who test positive for Covid-19 got the vaccine at a different rate than those who test negative. This will start with a study among healthcare workers to check that the vaccine’s overall efficacy is what is currently expected, followed by studies in severely affected or hospitalized patients, the elderly and those in long-term care facilities, and those with key underlying conditions, among other groups. Messonnier said that U.S. safety monitoring will be coordinated with international efforts to do the same, including those of the World Health Organization.

— Matthew Herper

How many vaccine EUAs can the FDA grant?

9:50 a.m.: Here’s an interesting question: If the FDA approves one Covid-19 vaccine, would that make it impossible to grant emergency use authorizations to future ones?

Panelist Jeannette Lee, a biostatistician from the University of Arkansas, raised the issue after an FDA official outlined the rules governing EUAs. Among them is a provision saying that an EUA is warranted when there’s no adequate, approved product for a particular indication. When it comes to Covid-19, wouldn’t that suggest that once the FDA grants full approval to a first vaccine, it would be precluded from bestowing EUAs on the ones to come?

The answer is no, according to Doran Fink, deputy director of the FDA’s vaccine division. If an approved product is available only in limited supply — as is certain to be the case with the first approved Covid-19 vaccine — the FDA can still grant EUAs to investigational products.

That means that we’ll be tuning into meetings like this on a regular basis for the months to come. But, if the U.S. meets its goals of securing hundreds of millions of vaccine doses by the summer, it also means that the next generation of Covid-19 vaccines might have to go through the FDA’s standard, non-EUA process.

— Damian Garde

NEJM editorial: Vaccine is a ‘triumph’

9:30 a.m.: As today’s FDA panel gets underway, one of the invited experts — and a voting member of the panel — has already expressed his opinion that the Pfizer/BioNTech Covid vaccine is a “triumph.”

Eric Rubin, an immunologist at the Harvard T.H. Chan School of Public Health, co-authored a laudatory editorial about the vaccine, published this morning in the New England Journal of Medicine. While highlighting minor issues with the clinical trial design, the vaccine results are “impressive enough to hold up in any conceivable analysis,” Rubin wrote.

He adds:

“This is a triumph. Most vaccines have taken decades to develop, but this one is likely to move from conception to large-scale implementation within a year. The sequence of the virus that led to the development of the specific antiviral RNA sequence required to design the vaccine didn’t become known until it had been determined and widely disseminated by the Chinese Center for Disease Control and Prevention in January 2020. There is a lot of credit to go around: to the scientists who shared data and who developed the underlying methods and implemented them to create a vaccine, to the clinical trialists who performed high-quality work in the setting of a health emergency, to the thousands of participants who volunteered to take part in the trial, and to the governments that helped create performance standards and a market for the vaccine. And all this stands as a template for the many other Covid-19 vaccines currently in development, some of which have already completed their phase 3 trials.”

The Phase 3 trial results from Pfizer/BioNTech were also published in NEJM this morning.

— Adam Feuerstein

Here we go!

9 a.m.: The meeting has just been called to order. It is streaming here, if you are interested in checking in.

The virtual audience for this meeting is expected to be large, and global. The world is watching how U.S. agencies are evaluating the effectiveness and safety of Covid-19 vaccines and how it’s thinking about prioritizing vaccine allocation.

How do we know? Well, nearly 32,000 computers in more than 66 countries and most parts of the United States were streaming the Dec. 1 meeting of the Advisory Committee on Immunization Practices, an expert panel that helps the Centers for Disease Control and Prevention assess vaccines and prioritize their use. It is not common that an ACIP meeting would garner that much attention.

During that meeting, ACIP members voted to recommend health care workers and residents of nursing homes get first access to Covid vaccines when supplies are limited.

The VRBPAC audience will likely be larger. The FDA is considered the gold standard for regulatory agencies. It is the only one that requires companies applying to bring a drug or vaccine to market to supply its raw data, which the agency’s scientists recalculate to ensure that the claims being made by the drug or vaccine sponsor are supported by the evidence.

Pro tip: If you’re wondering how long after today’s meeting it will take for FDA to decide on Pfizer’s emergency use authorization application, this afternoon’s discussion will be critical. Norman Baylor, a former director of FDA’s office of vaccines research and review, said Wednesday that if it seems like the committee members agree with the positive tone of the FDA’s review of the vaccine and vote unanimously to recommend an EUA be granted, things could move very rapidly.

If however, VRBPAC members — who have been poring over the Pfizer data in preparation for the meeting — raise a bunch of red flags, there could be delays, said Baylor, who is now president and CEO of Biologics Consulting.

— Helen Branswell

The FDA’s questions — and the placebo problem

8:45 a.m.: The FDA has posted the questions that the panel will be charged with discussing. The big one, the voting question, is no surprise:

“Based on the totality of scientific evidence available, do the benefits of the Pfizer-BioNTech COVID-19 Vaccine outweigh its risks for use in individuals 16 years of age and older?”

It would be a big surprise if the panel doesn’t vote positively, although I’d expect discussion about the meaning of each “yes.”

In addition to the voting question, there are two discussion questions:

1. “Please discuss any gaps in plans described today and in the briefing documents for further evaluation of vaccine safety and effectiveness in populations who receive the Pfizer-BioNTech Vaccine under an EUA.” 

2. “Pfizer has proposed a plan for continuation of blinded, placebo-controlled follow-up in ongoing trials if the vaccine were made available under EUA. Please discuss Pfizer’s plan, including how loss of blinded, placebo-controlled follow-up in ongoing trials should be addressed.”

I want to focus a bit on the second. This is going to be a big issue for all of the vaccine studies. Volunteers in these clinical trials generally expect that even if they were randomly assigned to get the placebo, they’ll be switched to the vaccine once it is effective.  Experts, in particular the ones on the VRBPAC panel, generally want to hold off the moment when placebo patients get the vaccine for as long as possible. Once it comes, the ability to compare the vaccine to a placebo to determine efficacy and side effects is lost.

But there’s another problem, which is that once a vaccine is available, patients may try to get it outside the trial, which is even worse from the perspective of getting good data than switching them over. A month ago STAT obtained a Pfizer memo saying that the company’s plan was to switch patients over as soon as they were eligible to receive the vaccine. There will be a lot more discussion of that plan all day, with time specifically allotted to this issue at 10:50.

— Matthew Herper

VRBPAC’s agenda

6 a.m.: Good day, folks. In honor of what promises to be an historic day, a crowd of us here at STAT— Matt, Adam, Damian and I — will be monitoring and live-blogging on the day’s discussions.

For starters, let’s introduce you to the committee members. The FDA has a very strict conflict of interest policy for VRBPAC members. Anyone involved in any of the Covid-19 clinical trials — even a member who works at a university that is a trial site — is “conflicted out,” which means that temporary replacements who are equally stringently vetted are named in their place.

The early part of the meeting, which begins at 9 a.m. EST, is about setting the table for the discussion that will follow. It includes discussion of what is happening in the U.S. outbreak right now, the plans for monitoring for adverse events potentially triggered by vaccination, as well as a presentation on distribution.

At or about 10:50 a.m. EST (VRBPAC discussions can run long) there will be an important discussion about what steps can be taken to ensure that issuing EUAs for some vaccines don’t interfere with the efforts to run placebo-controlled trials on others that are behind them in the pipeline. This is a thorny but critical issue.

After an early lunch, Pfizer will make a presentation on the vaccine. Then the FDA will make a presentation, which will lay out for committee members what issues the agency wants their advice on and what questions it wants them to answer by holding votes.

Then, starting at 3:10 p.m. EST (or thereabouts), the committee members will begin their deliberations. That’s crunch time.

— Helen Branswell

The context

The Covid-19 pandemic is raging around the world but most especially in the United States, which has the highest number of cases and deaths of any country on the planet. More than 15.3 million Americans have been diagnosed with Covid-19 and more than 288,000 have died.

The country has invested billions of dollars into fast-tracking development and production of Covid vaccines through a military-led project called Operation Warp Speed. While vaccines have been developed at an exceptional pace, there’s been a steady decline in the estimates of how quickly Americans will be vaccinated. Operation Warp Speed currently estimates it will have enough vaccine for 20 million people by the end of December — though vaccines in warehouses and vaccines in arms are two different things.

The administration now estimates that every American who wants to be vaccinated will be able to access vaccine by the end of the second quarter of 2021. Thursday’s hearing starts that process.

— Helen Branswell

Source: STAT