The Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to RSVpreF (PF-06482077), a respiratory syncytial virus (RSV) vaccine candidate, for the prevention of RSV-associated lower respiratory tract illness in infants from birth up to 6 months of age by active immunization of pregnant women.

The RSVpreF vaccine candidate consists of 2 prefusion F proteins selected to optimize protection against RSV A and B. The designation was based on positive topline results from a global, double-blind, placebo-controlled, proof-of-concept phase 2b study ( Identifier: NCT04032093) that evaluated the safety and immunogenicity of RSVpreF in healthy pregnant women 18 to 49 years of age who were vaccinated between 28- and 36-weeks gestation, and their infants.

“Today’s decision is a pivotal next step in our path towards potential regulatory approval for our maternal RSV vaccine candidate and is an important milestone in our efforts to help address the detrimental impact RSV disease has on infants,” said Kathrin U. Jansen, PhD, Senior Vice President and Head of Vaccine Research & Development at Pfizer Inc. “If approved by the FDA, this maternal immunization has the potential to be the first vaccine candidate to help protect infants in their vulnerable first months of life from disease caused by this highly-contagious virus.”

The Company is currently evaluating the efficacy, immunogenicity and safety of maternal immunization with RSVpreF in the phase 3 MATISSE study ( Identifier: NCT04424316), with results expected in the first half of 2022.

Additionally, RSVpreF is being investigated in adults 60 years of age and older in the phase 3 RENOIR study ( Identifier: NCT05035212). Top-line data are expected in the first half of 2022.


Pfizer granted FDA Breakthrough Therapy designation for respiratory syncytial virus (RSV) vaccine candidate for the prevention of RSV in infants from birth up to six months of age by active immunization of pregnant women. News release. Pfizer Inc. Accessed March 2, 2022.