Pfizer Eyeing Expedited FDA Approval for RSV Vaccine

February 23, 2023 - On Tuesday, Pfizer announced that the FDA accepted for review its Biologics License Application (BLA) for the company’s respiratory syncytial virus (RSV) vaccine candidate RSVpreF. Depending on the FDA’s decision expected in the second half of 2023, RSVpreF could be the first vaccine administered to pregnant individuals to protect their infants against RSV.

At a meeting this week, Pfizer will present data from the MATISSE Phase 3 clinical trial and two other clinical trials supporting regulatory filings for the company’s meningococcal and pneumococcal vaccine. The MATISSE trial met the statistical success criterion for severe medically attended lower respiratory tract illness (MA-LRTI) through the first 90 days of life. However, the trial failed to meet the second primary endpoint, only achieving clinically meaningful efficacy for MA-LRTI of 57.1% through the first 90 days of life.

The vaccine acts as an immunostimulant in the body that preps the immune system to deal with prefusion F, the viral fusion protein RSV uses to enter human cells. RSVpreF is the only vaccine candidate designed for newborns and individuals 60 or older - the two groups hardest hit by the virus. During the trial, there were no indications of safety concerns for the vaccine, and it was well tolerated by mothers and newborns.

“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,” said Annaliesa Anderson, PhD, Senior Vice President and Chief Scientific Officer, Vaccine Research & Development, Pfizer. “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 is not the only major pharmaceutical company striving for an RSV vaccine. Last month, Moderna announced that its ConquerRSV Phase 3 clinical trial met all primary efficacy endpoints for patients aged 60 years or more. Moderna’s mRNA vaccine for RSV uses the same platform implemented with the company’s COVID-19 vaccine. The most recent clinical trial represents the second time the company has found success with the vaccine platform, and it has solidified its goals of creating a suite of vaccines for respiratory diseases.

"Respiratory diseases are a major public health priority given they have a significant health impact and are a leading cause of hospitalization. In addition to our mRNA-1345 RSV vaccine candidate, we are committed to developing a portfolio of respiratory mRNA vaccines to target the most significant viruses causing respiratory disease, including COVID-19, influenza, and human metapneumovirus,” said Stéphane Bancel, Moderna's Chief Executive Officer in a press release.