FDA adcomm unanimous on J&J boosters for all

The vaccines advisory committee of the US Food and Drug Administration (FDA) voted unanimously Friday to recommend a full-strength booster dose of the COVID-19 vaccine made by Janssen, the vaccines arm of Johnson & Johnson, for all recipients of the single-dose primary vaccination.

The Vaccines and Related Biologic Products advisory committee (VRBPAC) recommended that FDA issue an emergency use authorization (EUA) for a booster to be given at least 2 months after the primary vaccine dose. The vote came after presentations from the sponsor and from FDA, though slide after slide of data in the agency’s presentation noted that FDA had not completed its own analysis of the safety and efficacy data submitted by Johnson & Johnson in support of its request for a booster EUA.

Peter Marks, director of FDA’s Center for Biologics Evaluation and Research (CBER), explained when queried that center staff had not had enough time to complete a full analysis of the large datasets included in the submission by the time of the VRBPAC meeting – and that it would take something approaching another month for them to do so. The ongoing original, global randomized controlled trial for the Janssen COVID-19 vaccine has enrolled over 30,000 people.

During discussion before voting, the committee came to consensus that a simplification of an original three-part voting question would better suit the data presented in support of boosters. Marks and his staff accordingly trimmed away two sub-questions asking the committee to weigh in on a 6-month interval between the primary and booster doses.

The sponsor presented data on just 17 individuals who received a booster at this interval, a number the committee deemed insufficient for decision-making, although the anamnestic response shown at the 6-month mark among those 17 participants was “more robust” than the response seen for those who received a booster at 2 months, according to Janssen’s data.

In one analysis presented by Janssen, the booster raised vaccine efficacy against symptomatic COVID-19 for US participants from 70% for those receiving one dose to 94% for people who received a booster. Johnson & Johnson was also able to demonstrate neutralizing antibodies against variants of concern, including the delta variant of SARS-CoV-2 that currently predominates in the US.

FDA presented updated safety data from its passive and active surveillance systems, which have to date identified risks of anaphylaxis, thrombosis with thrombocytopenia syndrome and Guillain-Barre syndrome. The agency is also tracking other potential risks including venous thromboembolism and immune thrombocytopenia; a pharmacovigilance plan submitted by the sponsor is tracking these concerns.

Despite concerns about sample sizes and other data issues, several committee members still maintained that the lower effectiveness of the Janssen COVID-19 vaccine against serious COVID-19 and hospitalization merited action; Marks pointed to a recent New England Journal of Medicine study showing that Janssen vaccine recipients had up to a 25% absolute increased risk of hospitalization compared with those who received an mRNA vaccine.

“In my mind, it was always going to be a 2-dose vaccine,” said committee member James Hildreth, president of Meharry Medical College, Nashville, TN.

Archana Chatterjee, Dean of the Chicago Medical School and a pediatric infectious disease expert, concurred, placing the discussion “in the context of 15 million people who have been vaccinated with a single dose and whose immunity might be waning.”

The single-dose initial regimen was an effective way to reach some populations, and that EUA was issued in the thick of the spike in cases seen in early 2021, noted Marks. Other committee members noted the benefits of a vaccine that does not need the ultra-cold storage temperatures that the mRNA vaccines require.

Added Chatterjee, “I’m in agreement with most of my colleagues who have suggested that this second dose, booster, whatever you want to call it, is necessary.”

FDA is not obligated to follow the recommendations of its advisory committees, though it usually does.

VRBPAC briefing materials and YouTube recordings

FDA adcomm unanimous on J&J boosters for all

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