Pfizer is prepared to press its lead in the maternal vaccination market for respiratory syncytial virus (RSV). Big Pharma is on track to gain a milestone FDA clearance by August, challenging AstraZeneca and Sanofi’s long-standing antibody in the market while former close competitor GSK remains embroiled in delays.
RSV is an infectious virus that frequently causes respiratory problems. Children, the elderly, and those with preexisting health concerns are most vulnerable to the virus’s devastating effects on the respiratory system. RSV infections cause over 2 million annual office visits and nearly 60,000 annual hospitalizations among kids under the age of five in the U.S.
Annaliesa Anderson, Chief Scientific Officer at Pfizer, said, “If approved, RSVpreF would help protect infants at their first breath from the devastating effects of this infectious disease, which though well-known, has been particularly evident throughout this RSV season. We look forward to progressing the review of Pfizer’s RSV maternal vaccine candidate with the FDA and other regulatory authorities, given its significant potential to positively contribute to global health in the prevention of RSV in infants.”
Pfizer halted a key study of its recombinant RSV prefusion vaccine candidate, RSVpreF, in November after an exploratory review. The risk of a severe lower respiratory tract illness necessitating medical attention in the first 90 days of the child’s life was found to be reduced by nearly 82% when RSVpreF was administered during pregnancy. Even though the trial failed to meet its primary goal, Pfizer was confident enough in the results to rush them to the appropriate authorities.
Now that an application for RSVpreF clearance has been approved for priority consideration by the FDA, Pfizer may expect to hear back with a decision by the end of August. Unless something catastrophic happens, RSVpreF will be the first maternal vaccination authorized to prevent RSV in infants between birth and six months.
Going into 2022, GSK was in a close race with Pfizer for this title, but a year earlier, in reaction to a safety review, it halted enrollment and immunization in three clinical tests of a maternal RSV vaccine, thereby ending its challenge. saiGSK’s chief of vaccine R&D, Phil Dormitzer, said that the company was hesitant to resume the maternal vaccination studies.
With GSK out of the running for the time being, Pfizer’s main competitors are AstraZeneca and Sanofi with their antibody nirsevimab. The FDA accepted the antibody for evaluation at the beginning of the year and gave AstraZeneca and Sanofi a resolution date in the third quarter, suggesting that nirsevimab and RSVpreF may both obtain clearance in the U.S. within weeks of one another.
Unlike nirsevimab, which is given after delivery, Pfizer’s maternal vaccination will provide protection from the time the baby is born, but its phase 3 results failed to knock the socks off the antibody in terms of effectiveness. Although it’s important to keep in mind that comparing results from different studies may not be the most trustworthy method, nirsevimab looks to be more efficacious than RSVpreF.
