Covid-19 roundup: FDA reveals booster adcomm question; Eli Lilly's antibody cocktail cleared for prevention
The FDA released briefing documents this week from the agency and Pfizer each outlining their arguments for today’s Covid-19 booster shot adcomm, but one thing conspicuously missing was the question on which panel members would be voting. But late Thursday night, regulators published that question.
Adcomm members will be asked whether or not the safety and efficacy data from Pfizer/BioNTech’s original Phase III study “support approval” of a booster shot at least six months after the second dose in individuals older than 16. The question notably excludes the real-world data from Israel and other analyses that Pfizer and the Biden administration had said would be a centerpiece of their arguments for boosters.
It’s not immediately clear whether this question would be the only one asked at the adcomm, but the FDA had yet to update its website as of early Friday morning.
Here’s the exact wording:
Do the safety and effectiveness data from clinical trial C4591001 support approval of a COMIRNATY booster dose administered at least 6 months after completion of the primary series for use in individuals 16 years of age and older? Please vote Yes or No.
Pfizer spent much of its 53-page briefing document on the various observational studies that have popped up during the Delta surge, showing the vaccine’s protection against mild disease waning over time but remaining very strong against severe Covid-19 and hospitalization. The FDA’s briefing documents, however, spent only two paragraphs addressing those studies, saying there is a lot that present “conflicting conclusions.”
The wording of the question differs considerably from those asked in the original vaccine adcomms last year, before any vaccine had been authorized or approved. Friday’s question focuses specifically on supporting approval, whereas the older questions asked whether or not the benefits of the vaccine outweighed the risks.
It’s a phrasing some outside observers struggled to interpret. Walid Gellad, director of the University of Pittsburgh Center for Pharmaceutical Policy and Prescribing, noted in a Twitter thread Thursday night the contrast between the question and the “narrow” focus on the Phase III study.
FDA posted the voting question for adcom tomorrow, but not sure how to interpret.
Do the safety and efficacy data from the 300 person booster trial support approval? Sure, they 'support it.' Are they sufficient for booster approval for all 16+? No. https://t.co/1x6tNOIH3H pic.twitter.com/x1IC636bZj
— Walid Gellad, MD MPH (@walidgellad) September 17, 2021
— Max Gelman
FDA expands EUA for Eli Lilly’s antibody cocktail to cover prevention
Eli Lilly and AbCellera are squarely back in action.
Just days after the US resumed distribution of their antibody cocktail nationwide to fight against a surge in cases — dominated by the Delta variant — the companies said the combo of bamlanivimab and etesevimab has been cleared for emergency use to prevent Covid-19 in people who have been exposed to someone infected with SARS-CoV-2 or at high risk of exposure, such as in the prison or nursing home setting.
It marks the second EUA the FDA has issued for post-exposure prophylaxis, after granting the same expansion for Regeneron’s antibodies.
On top of protecting people who have not been fully vaccinated, Lilly notes that individuals who can’t mount an adequate immune response to complete vaccination may benefit from the drugs. It’s sanctioned for high-risk individuals 12 or older.
The combination of a low vaccination rate and a rise in breakthrough Covid-19 cases has translated to skyrocketing demand for monoclonal antibodies. Just days ago, Regeneron revealed the government has placed a new, $2.9 billion order for 1.4 million additional doses of its antibodies.
Lilly had licensed bamlanivimab from AbCellera and etesevimab from Shanghai’s Junshi to put together the combo.
“The expanded use authorization for bamlanivimab together with etesevimab provides a way to protect the significant number of people who, because of their situational exposure risk or medical condition, remain vulnerable to COVID-19,” AbCellera CEO Carl Hansen said in a statement. “More than 535,000 patients have been treated with bamlanivimab alone or together with etesevimab, potentially keeping more than 25,000 patients out of the hospital and saving more than 10,000 lives.”
— Amber Tong
Researchers peg AstraZeneca/Oxford, Pfizer/BioNTech vaccine immunity about 1 year
A group of Oxford scientists says the Covid-19 vaccine that their colleagues have developed with AstraZeneca appears to kick up antibodies that last equally as long as the ones elicited by Pfizer and BioNTech’s rival shot.
Analyzing anti-spike IGG antibody responses among 186,527 vaccinated people in the UK to figure out the duration of protection offered by the two vaccines, the researchers concluded:
Protection based on current positivity thresholds can last for at least 0.5-1 year for ChAdOx1 and over a year for BNT162b2; however, given the reduced effectiveness against variants of concern, the duration of protection may be significantly reduced. These results may inform vaccination strategies; a third boosting dose may be needed, and could be prioritised to the more vulnerable population groups.
They also found that no matter when it’s given after the first dose, a second dose of ChAdOx1 and BNT162b2 induced “significant boosting” of anti-spike antibodies targeting SARS-CoV-2.
There was, however, a key difference: Antibody levels declined faster for younger individuals after a second dose of the Oxford/AstraZeneca vaccine, while older people getting BNT162b2 saw their levels decline faster — although it was offset by higher peak levels.
“In the most vulnerable groups, the net effect was a similar duration of time above different thresholds from the two vaccines, but with longer durations with BNT162b2 in younger groups,” they added.
Notably, they also offered a counterpoint to recent studies that suggested longer dosing intervals may generate more immunity, suggesting that the differences in antibody levels may be related to how and when those studies measured antibody levels.
— Amber Tong