Bivalent RSV Maternal Vaccine Candidate Gets FDA’s Priority Review

The BLA is supported by data from a phase 3 trial which included approximately 7400 pregnant individuals.

The Food and Drug Administration (FDA) has accepted for Priority Review the Biologics License Application (BLA) for RSVpreF (PF-06928316), a bivalent respiratory syncytial virus (RSV) vaccine candidate for administration to pregnant individuals to help protect against the complications of RSV disease in infants from birth through 6 months.

The RSVpreF vaccine candidate consists of 2 prefusion F proteins selected to optimize protection against RSV A and B. The BLA is supported by data from the randomized, double-blind, placebo-controlled phase 3 MATISSE trial ( Identifier: NCT04424316), which evaluated the efficacy and safety of RSVpreF in approximately 7400 pregnant individuals (≤49 years of age) who were between 24 and 36 weeks of gestation.  

Results showed vaccine efficacy of 81.8% (CI, 40.6-96.3) against severe medically attended lower respiratory tract illness (MA-LRTI) in infants from birth through the first 90 days of life. Efficacy of 69.4% (CI, 44.3-84.1) was observed over the 6-month follow-up period.

While the second primary endpoint did not meet statistical significance, vaccine efficacy against MA-LRTI was reported to be 57.1% (CI, 4.7-79.8) in infants from birth through the first 90 days of life and 51.3% (CI, 29.4-66.8) over the 6-month follow up period. No safety concerns were noted for the vaccinated individuals or the infants. “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.”

A Prescription Drug User Fee Act target date of August 2023 has been set for the application. The FDA previously granted Breakthrough Therapy designation to RSVpreF for this indication.


US FDA accepts Biologics License Application for Pfizer’s respiratory syncytial virus maternal vaccine candidate for Priority Review. News release. Pfizer Inc. Accessed February 21, 2023.