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VRBPAC: Another thumbs up, this time for Moderna's COVID vaccine

Posted 17 December 2020 | By Kari Oakes 

VRBPAC: Another thumbs up, this time for Moderna's COVID vaccine

An advisory committee to the US Food and Drug Administration (FDA) has registered an overwhelmingly favorable vote for the COVID-19 vaccine co-developed by Moderna and the National Institutes of Health.
 
After a day-long meeting, FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted 20-0, with one abstention, in favor of the proposition that Moderna’s messenger RNA (mRNA) vaccine’s benefits outweighed its risks for individuals 18 years old and up.
 
FDA and the sponsor agreed in their presentations that overall efficacy was over 94% in a clinical trial of more than 30,000 participants, and that the safety profile seen in an interim analysis raised no red flags.
 
The vaccine is intended to be given in a prime-boost regimen with the two doses given 28 days apart. As with the Pfizer-BioNTech mRNA vaccine, COVID-19 vaccine rates declined among vaccine recipients after the first dose, though neither vaccine candidate is currently being studied in a single-dose regimen.
 
Though FDA is not required to follow the recommendations of its advisory committees, it usually does so; last week’s emergency use authorization (EUA) for the first vaccine against COVID-19 came on the day after VRBPAC gave the Pfizer-BioNTech vaccine the green light. (RELATED: FDA authorizes Pfizer-BioNTech vaccine for emergency use, Regulatory Focus 11 December 2020)
 
Introducing the EUA criteria, FDA’s Doran Fink, MD, PhD, clarified that the previous week’s rollout of emergency use of the first COVID-19 vaccine would not stand in the way of this EUA, since “there is currently no approved, available and adequate preventive vaccine for COVID-19,” said Fink.
 
FDA’s review of the Moderna data was based on data acquired up to a cutoff of 7 November for efficacy, together with a primary dataset with an efficacy cutoff of 21 November. Moderna submitted a supplement to its application that was also made available for VRBPAC members to review. However, noted FDA in its own briefing document, the agency conducted its own independent review and analysis of data just from the first dataset.
 
The day’s agenda afforded more time for back-and-forth among committee members than the previous week’s packed agenda to review the Pfizer-BioNTech EUA materials. Members took this extra time to weigh in on a range of considerations, framed partially by the additional discussion question that was put before the committee. After the topic received short shrift at the previous week’s meeting, FDA explicitly asked VRBPAC to consider how to balance the need to accrue vaccine safety and effectiveness data against ethical and practical considerations that might favor early unblinding of placebo recipients.
 
Moderna’s proposal to address unblinding the placebo arm took into consideration the fact that about one in four trial participants are healthcare workers, who are early in line to receive vaccines – and are seeing their peers currently receiving the Pfizer vaccine. “We need to realize that trial participants are going to want to know what arm they are in; they are going to walk” if they are not given the opportunity for unblinding, said committee member Robert Schooley, MD, of the University of California-San Diego.
 
The sponsor’s proposal would have placebo recipients offered vaccine at the point in time it would otherwise be available to them, given their eligibility status and geographic location.
 
Though this proposal would help keep participants enrolled and not exiting the study in order to receive the vaccine, it does not square with the ideal scenario proposed by guest speaker Steven Goodman, MD, PhD, of Stanford University. Goodman, who also spoke last week, proposed a blinded crossover trial design that several committee members praised in theory, but that many VRBPAC members deemed impractical to implement at this point.
 
Moving to the voting question, VRBPAC acting chair Arnold Monto, MD, of the University of Michigan, suggested adjusting the wording of the question to limit the committee’s vote to a favorable benefit-risk profile for the purposes of an EUA. Several other committee members proposed other adjustments to the wording.
 
In the end, two committee members who also attend the US Centers for Disease Control and Prevention’s (CDC’s) vaccines advisory committee asked the committee to leave the wording as is. Amanda Cohn, MD, a CDC chief medical officer, first weighed in against changes. Paul Offitt, MD, professor of pediatrics and infectious diseases at the Children’s Hospital of Philadelphia, concurred. Said Offitt: “The question is not 'When do you know everything?' but 'When do you know enough?'"
 
Just one committee member, Michael Kurilla, MD, PhD, expressed discomfort with giving the thumbs up to the Moderna vaccine. Kurilla, who directs the Division of Clinical Innovation at the National Center for Advancing Translational Sciences at the National Institutes of Health, said he was “uncomfortable with the wording” of the voting question, finding it excessively broad. “I’m not convinced the benefits actually do outweigh the risks at this point,” said Kurilla, who would have favored an expanded access mechanism over the EUA.
 
Should an EUA be issued, 6 million doses of the Moderna vaccine will be shipped to locations around the country. Moderna received support from the US government vaccine accelerator Operation Warp Speed, in addition to its collaboration with the National Institutes of Health.
 
The briefing materials are available on the FDA’s website, and the meeting was livestreamed on YouTube and Twitter in addition to the FDA’s usual webcast.
 
FDA

 

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Tags: coronavirus, FDA, US

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