The US Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation to Pfizer’s respiratory syncytial virus (RSV) vaccine candidate, PF-06928316 or RSVpreF. 

RSVpreF is an investigational vaccine candidate that comprises two preF proteins chosen to enhance protection against RSV A and B.

It is intended for active vaccination of pregnant women to prevent lower respiratory tract illness linked to RSV infection in infants from birth up to six months of age. 

The latest decision is based on the data from the double-blinded, international, placebo-controlled Phase IIb proof-of-concept clinical trial of RSVpreF.

The trial analysed the safety and immunogenicity of the vaccine in healthy pregnant women of the age 18 to 49 years who received the vaccine during the 28 and 36 weeks of gestation and their infants. 

Results from this trial will be published in the future, the company noted.

This latest development comes after the regulatory agency’s November 2018 decision for granting Fast Track status to the vaccine. 

Pfizer Vaccine Research & Development senior vice-president and head Kathrin Jansen said: “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. 

“If approved by the FDA, this maternal immunisation 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. 

“We look forward to our ongoing dialogue with the FDA to accelerate the development of our maternal RSV vaccine candidate.”

In December last year, the US FDA granted an emergency use authorisation (EUA) for Pfizer’s oral antiviral Paxlovid for the treatment of mild-to-moderate Covid-19 in adults and paediatric individuals aged 12 years and above.