The 50-year race to develop an RSV vaccine turned a corner on Thursday with Pfizer unveiling promising pivotal data for its bivalent RSV vaccine candidate, promising to take the data to the FDA ahead of several rivals in a market that could stretch to $10 billion by 2030.
In assessing protection against RSV-associated lower respiratory tract illness (LRTI-RSV), defined by two or more symptoms, Pfizer said the candidate demonstrated vaccine efficacy of 66.7% (96.66% CI: 28.8%, 85.8%) in a placebo-controlled Phase III trial with about 37,000 participants.
And for the more severe disease primary endpoint of LRTI-RSV defined by three or more symptoms, Pfizer said the vaccine’s efficacy jumped to 85.7% (96.66% CI: 32.0%, 98.7%). The data monitoring committee also indicated the investigational vaccine was well-tolerated, with no safety concerns, the company noted.
In the US, the CDC estimates that more than 177,000 adults over the age of 65 are hospitalized from RSV, and 14,000 die each year.
“We are delighted that this first bivalent RSV vaccine candidate, RSVpreF, was observed to be efficacious in our clinical trial against this disease, which is associated with high levels of morbidity and mortality in older adults,” said Annaliesa Anderson, SVP and chief scientific officer of vaccine R&D at Pfizer, said in a statement.
Pfizer intends to present the results of this interim analysis at a future medical congress and will submit the results for peer review in a scientific journal.
Meanwhile, rivals GSK, Moderna and Johnson & Johnson are also racing to finish their own RSV vaccine trials.
GSK said its pivotal trial results in older adults could come in the second half of this year, although the company recently announced that the vaccine candidate showed a statistically significant reduction in lower respiratory tract infections in older adults.
J&J launched its pivotal adult RSV vaccine trial in September 2021 but doesn’t expect data until next June.
The Boston-based mRNA powerhouse Moderna is also developing a multivalent vaccine that could potentially protect against RSV, flu and Covid-19, although key opinion leaders told SVB Leerink that the US is years away from a triple combo vaccine “due to efficacy and technical hurdles to approval.”
“We believe that PFE’s COVID vaccine commercial infrastructure will enable a rapid global launch if their RSV vaccine is approved and therefore represents significant competition to GSK’s program,”
former analyst
Geoffrey Porges wrote in an investor note back in 2021.
Novavax also
took a shot
at RSV but saw its pivotal trial flop in 2016.
Several other companies like Enanta, which saw
disappointing data recently
, and Sanofi are also working on antiviral and mAb therapies for RSV.