No second-class vaccines
The Johnson & Johnson vaccine, known as Ad26.COV2.S, is composed of a recombinant, replication-incompetent human adenovirus type 26 (Ad26) vector. It’s intended to encode a stabilized form of SARS-CoV-2 spike (S) protein. The Pfizer and Moderna vaccines use a different mechanism. They rely on mRNA.
The FDA advisers also discussed how patients might respond to the widely reported gap between Janssen’s topline efficacy rates compared with rivals. They urged against people parsing study details too finely and seeking to pick and choose their shots.
“It’s important that people do not think that one vaccine is better than another,” said FDA adviser H. Cody Meissner, MD, from Tufts University School of Medicine in Boston.
Dr. Monto agreed, noting that many people in the United States are still waiting for their turn to get COVID vaccines because of the limited early supply.
Trying to game the system to get one vaccine instead of another would not be wise. “In this environment, whatever you can get, get,” Dr. Monto said.
During an open public hearing, Sarah Christopherson, policy advocacy director of the National Women’s Health Network, said that press reports are fueling a damaging impression in the public that there are “first and second-class” vaccines.
“That has the potential to exacerbate existing mistrust” in vaccines, she said. “Public health authorities must address these perceptions head on.”
She urged against attempts to compare the Janssen vaccine to others, noting the potential effects of emerging variants of the virus.
“It’s difficult to make an apples-to-apples comparison between vaccines,” she said.
Johnson & Johnson’s efficacy results, which are lower than those of the mRNA vaccines, may be a reflection of the ways in which SARS-Co-V-2 is mutating and thus becoming more of a threat, according to the company. A key study of the new vaccine, involving about 44,000 people, coincided with the emergence of new SARS-CoV-2 variants, which were emerging in some of the countries where the pivotal COV3001 study was being conducted, the company said.
At least 14 days after vaccination, the Johnson & Johnson COVID vaccine efficacy (95% confidence interval) was 72.0% (58.2, 81.7) in the United States, 68.1% (48.8, 80.7) in Brazil, and 64.0% (41.2, 78.7) in South Africa.
Several researchers called on the FDA to maintain a critical attitude when assessing Johnson & Johnson’s application for the EUA, warning of a potential for a permanent erosion of agency rules due to hasty action on COVID vaccines.
They raised concerns about the FDA demanding too little in terms of follow-up studies on COVID vaccines and with persisting murkiness resulting in attempts to determine how well these treatments work beyond the initial study period.
“I worry about FDA lowering its approval standards,” said Peter Doshi, PhD, from The BMJ and a faculty member at the University of Maryland School of Medicine in Baltimore, during an open public hearing at the meeting.
“There’s a real urgency to stand back right now and look at the forest here, as well as the trees, and I urge the committee to consider the effects FDA decisions may have on the entire regulatory approval process,” Dr. Doshi said.
Dr. Doshi asked why Johnson & Johnson did not seek a standard full approval — a biologics license application (BLA) — instead of aiming for the lower bar of an EUA. The FDA already has allowed wide distribution of the Pfizer/BioNTech and Moderna vaccines through EUAs. That removes the sense of urgency that FDA faced last year in his view.
The FDA’s June 2020 guidance on the development of COVID vaccines had asked drugmakers to plan on following participants in COVID vaccine trials for “ideally at least one to two years.” Yet people who got placebo in Moderna and Pfizer trials already are being vaccinated, Dr. Doshi said. And Johnson & Johnson said in its presentation to the FDA that if the Ad26.COV2.S vaccine were granted an EUA, the COV3001 study design would be amended to “facilitate cross-over of placebo participants in all participating countries to receive one dose of active study vaccine as fast as operationally feasible.”
“I’m nervous about the prospect of there never being a COVID vaccine that meets the FDA’s approval standard” for a BLA instead of the more limited EUA, Dr. Doshi said.
Diana Zuckerman, PhD, president of the nonprofit National Center for Health Research, noted that the FDA’s subsequent guidance tailored for EUAs for COVID vaccines “drastically shortened” the follow-up time to a median of 2 months. Dr. Zuckerman said that a crossover design would be “a reasonable compromise, but only if the placebo group has at least 6 months of data.” Dr. Zuckerman opened her remarks in the open public hearing by saying she had inherited Johnson & Johnson stock, so was speaking at the meeting against her own financial interest.
“As soon as a vaccine is authorized, we start losing the placebo group. If FDA lets that happen, that’s a huge loss for public health and a huge loss of information about how we can all stay safe,” Dr. Zuckerman said.
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