Surprise! Pfizer jumps the queue and leaps into RSV vax contention as COVID helps turbocharge work

Watch out, GlaxoSmithKline and Johnson & Johnson, Pfizer is steaming into the respiratory syncytial virus (RSV) vaccine race in what looks like a late break that could soon become gold.



In data dropped rather quietly during second-quarter earnings this week and to little fanfare, Pfizer said a challenge study, where vaccines were given to 62 adults under 50 who were then intentionally infected with RSV to see if the shot worked, showed “100% observed efficacy against mild to moderate symptomatic infection resulting from RSV.”  



This is only a peek from the phase 2a test, which is set up to assess the immunogenicity and efficacy of the bivalent protein-based vaccine candidate, RSVpreF. But the data, which came out of nowhere, could be a boon for Pfizer and came with no serious safety worries.



More specifics and details are coming, and that’s where the real analysis will come. But Pfizer likes what it sees and plans to kickstart a global phase 3 trial in adults this September based on these data, with results expected as early as the first quarter of next year.


RELATED: Pfizer now expects COVID vaccine sales to reach $33.5B this year, a whopping $7.5B bump from its estimate 3 months ago


Analysts at SVB Leerink said: “We expect this move may surprise many investors who expected GSK and J&J to lead the adult RSV vaccine race.”



After talking with Pfizer, which Leerink said had been deliberately stealthy about the program, the pharma shared a little extra data suggesting that among 31 vaccinated individuals, mean RSV viral load did not increase within 12 days after challenge, compared to a 2-3 log fold mean increases among 31 placebo group members.



The company also disclosed to the firm a symptom score measure “that suggested that vaccinated trial participants expected fewer disease symptoms.”



The COVID effect


Pfizer is riding high on what must be one of the most savvy/lucky biotech deals ever made, when it decided last spring to work with little-known German outfit BioNTech and its mRNA tech against COVID. The deal will now bring in, according to Pfizer's latest estimates, $33 billion this year alone, and that’s before boosters.  



In fact, this COVID work has helped spur Pfizer on in RSV.

“Pfizer’s aggressive timeline appears inspired by the 'lightspeed' operational planning carried over from their COVID vaccine efforts,” Leerink added in its note to clients.

RELATED: GSK culls phase 2 RSV vaccine in kids, as feladilimab flops again in lung cancer

The RSV asset is set for 2026 sales of just $255 million, according to EvaluatePharma, though the entire market could be $7 billion a year in adults alone, according to Leerink, so there is much up for grabs.

That’s a far cry from the mega blockbuster COVID vaccine, which I’m sure Pfizer won’t mind us hoping won’t be needed in 2026.  

Pfizer's surprise data drop comes amid a setback for GSK this week, which abandoned its RSV candidate in kids, while moving forward with a maternal vaccine test to protect mothers and children during and from birth. Results are expected in 2024. Pfizer is running a similar phase 3 in pregnant women. J&J, meanwhile, has an RSV vaccine, Ad26.RSV.preF, in a phase 3.

The race is on.




The toll of RSV


Cold viruses often don’t get much of a look when it comes to R&D. They are annoyances, but ones that usually make us feel miserable for a few days then clear up.



But some cold viruses can hit vulnerable people much harder, leading to pneumonia and hospitalizations. These are colds caused by RSV, which, in the elderly and children under 5, can cause serious complications and sometimes prove fatal.



In younger children, it can cause bronchiolitis, or inflammation and congestion of the small airways or bronchioles of the lung. The virus is thought to cause about 3 million hospitalizations of children under 5 globally, with around 177,000 hospitalizations of older people in the U.S.


RELATED: AstraZeneca, Sanofi post RSV data ahead of 2022 approval filings


A number of Big Pharmas have attempted a vaccine, but the road has been fraught with setbacks and flops. Novavax, also in the COVID running, knows this all too well. There is a monthly preventive shot from Swedish Orphan Biovitrum, called Synagis, which can be used against RSV in high-risk infants, but a fully protective vaccine remains elusive.



After a major lull in RSV infections across the world during last winter as masks and isolation cut rates dramatically, the great re-opening could see the virus surge back, so the need for vaccines has become paramount.