FDA Accepts Biologics License Application for RSV Maternal Vaccine Candidate

Officials with the FDA have accepted a Biologics License Application from Pfizer for its respiratory syncytial virus (RSV) maternal vaccine candidate for priority review, with an action date for August 2023.

If approved, the vaccine, called RSVpreF, would be the first immunization approved for administration in pregnant individuals to help protect against the complications of RSV in infants from birth through 6 months. The vaccine candidate recently had a Marketing Authorization Application accepted by the European Medicines Agency under accelerated assessment for both older adults and maternal immunization.

RSV is a contagious virus and a common cause of respiratory illness. It can affect the lungs and breathing passages, and can potentially cause severe illness in young infants, older adults, and individuals with some chronic medical conditions.

Among children younger than 5 years of age in the United States, RSV infections account for approximately 2.1 million outpatient visits and 58,000 hospitalizations each year. Virtually all children have an RSV infection by age 2 and it is a leading cause of hospitalization in children less than 1 year of age. Globally, RSV results in the death of approximately 102,000 children annually, with about half of those in infants younger than 6 months.

Among adults 65 years of age and older, RSV infections account for approximately 60,000 to 160,000 hospitalizations and between 6000 and 10,000 deaths each year in the United States. There are currently no targeted prophylactic, therapeutic, or vaccine options for RSV in older adults, and treatment is limited to supportive care.

The investigational RSVpreF vaccine builds on foundational discoveries at the National Institutes of Health (NIH), which detailed the crystal structure of prefusion F, a form of the viral fusion protein (F) that RSV uses to enter human cells. The NIH research demonstrated that antibodies specific to the prefusion form were highly effective at blocking virus infection, suggesting that a prefusion F-based vaccine may confer optimal protection against RSV.

Following this discovery, researchers at Pfizer tested numerous versions of a stabilized prefusion F protein and identified a candidate that elicited a strong antiviral immune response in pre-clinical evaluations. The bivalent vaccine candidate is composed of equal amounts of recombinant RSV prefusion F from subgroups A and B.

“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 evidence throughout this RSV season,” said Annaliesa Anderson, PhD, senior vice president and chief scientific officer of vaccine research and development at Pfizer, in a press release.

The maternal immunization regulatory submission is supported by the positive top-line results from the phase 3 MATISSE trial, which evaluated the efficacy, safety, and immunogenicity of RSVpreF against medically attended lower respiratory tract illness (MA-LRTI) and severe MA-LRTI in infants born to healthy women vaccinated during pregnancy. The data will be presented in the upcoming CDC Advisory Committee on Immunization Practices meeting on February 23, and during the ReSViNET Foundation’s 2023 Global Conference on Novel RSV Preventive and Therapeutic Interventions.

“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,” Anderson said in the press release.

REFERENCE

US FDA Accepts Biologics License Application for Pfizer’s Respiratory Syncytial Virus Maternal Vaccine Candidate for Priority Review. News release. Pfizer; February 21, 2023. Accessed February 22, 2023. https://www.pfizer.com/news/press-release/press-release-detail/us-fda-accepts-biologics-license-application-pfizers