US Food and Drug Administration officials may allow some wiggle room with the coronavirus vaccine safety recommendations that garnered the ire from the White House in recent days.
The expectation for a vaccine candidate to be considered for an emergency use authorization is that Phase III clinical trials include a median of two months of safety follow-up. But Center for Biologics Evaluation and Research Director Peter Marks said that unlike some European jurisdictions, the FDA is not going to demand that exact number of months for every patient. He said assessors will look at the totality of the data in the submission.
“We're flexible. We're not going to be completely flexible,” Marks said during a 5 October Journal of the American Medical Association event. “If it turns out the median is seven weeks and not two months, that's not going to be an issue.”
Marks added that if the EUA request arrives with less than a median of two months of follow-up, the candidate could reach the bar during the FDA assessment, since the clinical trials would remain ongoing.
“That still means that the safety profile of a vaccine that is going to be deployed in millions of people has to be incredibly clean,” he said. “When you're going to deploy something in millions of individuals we need that kind of robust safety data. We need to have a strong efficacy signal.”
Marks has indicated that the efficacy data requirements for an EUA request is likely to be similar to a biologics license application. (Also see "US FDA Expects COVID-19 Vaccines To Meet ‘EUA Plus’ Standards, Marks Says" - Pink Sheet, 10 Sep, 2020.)
The two-month safety benchmark is based on an FDA analysis of the timing of adverse events in other vaccines. (Also see "US FDA’s Two-Month Safety Window For COVID Vaccines Based On Adverse Events In Other Products" - Pink Sheet, 28 Sep, 2020.)
Marks and others repeatedly have indicated that vaccine sponsors know the safety data standard, despite efforts by the White House to nix it and other requirements. Reportedly, White House officials refused to allow the FDA to release a long-expected guidance on EUA standards for a coronavirus vaccine, in part because of they said there was industry opposition.
CBER officials made an end-run on 6 October when they published the briefing documents for the upcoming Vaccines and Related Biological Products Advisory Committee meeting on coronavirus vaccine development and approval issues.
Included in the documents for the 22 October meeting is a “Summary of Advice Provided to Individual Sponsors In Response to Questions Regarding Emergency Use Authorization of Vaccines to Prevent COVID-19.” There it states that Phase III data should include “a median follow-up duration of at least two months after completion of the full vaccination regimen to help provide adequate information to assess a vaccine’s benefit-risk profile.”
Later in the day, the FDA released the long-awaited guidance with much of the same information. (See box for more coverage of the politics and practicalities of the guidance.)
Pfizer Inc., one of the sponsors leading the vaccine race, denied that the company opposed the criteria outlined in the guidance. The company said in a statement that it is “committed to bringing a vaccine to market that complies with the FDA’s criteria for safety, efficacy, and manufacturing” and “will support and meet or exceed whatever FDA guidance comes out of” the upcoming VRBPAC meeting.
Pfizer Chairman and CEO Albert Bourla also tweeted that the company has never discussed the FDA’s coronavirus vaccine guidelines with the White House and never would do so because it would undermine FDA independence. The FDA’s “public servants are known for their high integrity and scientific expertise and we have full faith in their ability to set appropriate standards for the approval of a COVID vaccine or treatment,” Bourla said in a tweet.
Application Expected Before End Of 2020
Marks said it’s possible an application could arrive “before the end of the year in terms of an emergency use authorization application from some company.”
“It's unfortunate that we're having so many cases, but with some of the trials now fully enrolled, they're just accruing cases, so hopefully we'll see something by then,” Marks said. “I don't know for sure at all.”
Once a candidate arrives, Marks said an EUA request should move through the assessment process much faster than a BLA.
“Depending on how much we have up front in terms of information that's come to us before the actual arrival of the EUA, and depending on the complexity of the EUA, it's probably going to take a matter of weeks,” he said. “But we're talking about weeks as opposed to months. A biologics license application, even a very well put together one, will take us a few months at least to get through because it's just such a mass of information.”
Mark's review timetable is even more optimistic than that of his politically-appointed boss. FDA Commissioner Stephen Hahn told a Senate hearing in September that review of a vaccine application could take weeks or months. (Also see "Hahn Says COVID Vaccine Review Could Take Months As Trump Floats Rejecting New EUA Guidance" - Pink Sheet, 23 Sep, 2020.)
The timing of an EUA authorization in particular is the subject of some conjecture. President Trump has said multiple times that a vaccine could be made available by the 3 November election. However, that timeline seems to be in doubt with the calendar turned to October. (Also see "EUA For COVID-19 Vaccine Would Mean Fewer Patient-Years Of Follow-Up But More Pharmacovigilance" - Pink Sheet, 2 Oct, 2020.)
Trump tweeted that the guidance, which seems to all but eliminate the chance of a vaccine by election day, was “another political hit job!”
VRBPAC ‘Augmented’ With Experts
Marks also indicated that, as expected, the VRBPAC’s make-up has been adjusted for the upcoming meetings on coronavirus vaccines.
He said the committee “has been augmented with some experts in coronavirus and some experts in statistical analysis.” They also will be made special government employees and vetted for conflicts of interest.
The current roster includes a number of infectious disease and vaccine safety experts. Ethicists and specialists in specific adverse event areas also may be needed. (Also see "US FDA COVID-19 Adcom: What Additional Members Are Needed?" - Pink Sheet, 17 Aug, 2020.)
In addition, Marks reiterated that the meeting will be made available for television broadcast in addition to streamed online. The meeting’s expected high viewership could strain the FDA’s Internet capabilities. (Also see "Televise The COVID-19 Vaccine Advisory Committee Meetings" - Pink Sheet, 28 Sep, 2020.)