Pfizer joins GSK in RSV success

Words by GOLD newsdesk

Pfizer plans to file for approval for its respiratory syncytial virus (RSV) vaccine for infants by the end of 2022 after achieving positive top-line data results in its Phase 3 trial, the company has announced.


In the trial, the maternal vaccine showed an efficacy of 81.8% against severe medically attended lower respiratory tract illness caused by RSV in infants from birth in the first 90 days of life. The candidate also showed an efficacy of 69.4% in preventing the disease in the first six months of an infant’s life.


If approved, the vaccine could become the first to help prevent the RSV illness in young infants. The disease is estimated to kill more than 100,000 children a year worldwide.


“We are thrilled by these data as this is the first-ever investigational vaccine shown to help protect newborns against severe RSV-related respiratory illness immediately at birth,” said Annaliesa Anderson, Senior Vice President and Chief Scientific Officer, Vaccine Research and Development, Pfizer.


While the results are a cause for celebration for Pfizer, the candidate only met one of its two primary endpoints, meaning it could still face fierce competition from a rival vaccine solution developed by AstraZeneca and Sanofi. This was recommended for approval in the EU by the Committee for Medicinal Products for Human Use in September 2022.


Pfizer's trial results come as further RSV vaccine developments were announced by GSK. The Marketing Authorization Application for its RSV older adult vaccine candidate has been accepted by EMA under accelerated assessment, and it has also been granted Priority Review by the FDA, reducing the review period by four months. A decision is now expected by 3 May 2023. These mark the second and third major regulatory milestone for the vaccine candidate following acceptance of regulatory submissions in Japan last month.


Until February 2022, GSK was also investigating its candidate for maternal use, but stopped enrollment in its study following an unfavourable observation from a routine safety assessment.