FDA Grants Priority Review to Pfizer's RSV Vaccine Candidate for Older Adults

The FDA has granted priority review to a Biologics License Application (BLA) for Pfizer’s respiratory syncytial virus (RSV) vaccine candidate, PF-06928316 (RSVpreF), to prevent lower respiratory tract disease caused by RSV in patients aged 60 years and older. There are currently no approved prophylactic vaccines for RSV in older adults, with only supportive care available.

“With no RSV vaccines currently available, older adults remain at-risk for RSV disease and potential severe outcomes, including serious respiratory symptoms, hospitalization, and in some cases, even death,” Annaliesa Anderson, PhD, Pfizer senior vice president and chief scientific officer, Vaccine Research & Development, said in a press release. “The FDA’s acceptance of the BLA for our RSV vaccine candidate is an important regulatory milestone in Pfizer’s efforts to help protect older adults against RSV and demonstrates additional progress toward what has been an elusive public health goal—reducing the overall burden associated with this infectious disease.”

RSV is a contagious virus and a common cause of respiratory illness that can affect the breathing passages and lungs of infected individuals. Further, RSV is potentially life-threatening to infants.

Among older US adults, RSV infections account for approximately 60,000–120,000 hospitalizations and 6000–14,000 deaths each year. In US children younger than 5 years of age, RSV infections are responsible for approximately 2.1 million outpatient visits and 58,000–80,000 hospitalizations each year.

According to Pfizer, RSVpreF is based on foundational basic science discoveries, such as findings from the National Institutes of Health (NIH), detailing the crystal structure of prefusion F, a vital form of the viral fusion protein (F) used by RSV to attack human cells. NIH research indicates that antibodies specific to the prefusion form had high efficacy preventing viral infection. This indicates that a prefusion F-based vaccine may provide optimal protection against RSV, according to Pfizer.

The BLA submission was based on findings from the phase 3 (NCT05035212) RENOIR (RSV vaccine Efficacy study iNOlder adults Immunized against RSV disease) trial.

The global, randomized, double-blind, placebo-controlled study evaluated the efficacy, immunogenicity, and safety of a single dose of RSVpreF in adults 60 years of age and older. The study randomized approximately 37,000 participants to receive RSVpreF 120 μg or placebo in a 1:1 ratio. Pfizer previously announced positive top-line findings from an interim efficacy analysis for RENOIR.

The analysis showed that RSVpreF produced vaccine efficacy of 66.7% (96.66% CI: 28.8%, 85.8%) against RSV-associated lower respiratory tract illness (LRTI-RSV) as defined by 2 or more symptoms. This finding prompted researchers to examine the more severe disease primary endpoint of LRTI-RSV as defined by 3 or more symptoms, which showed an efficacy rate of 85.7% (96.66% CI: 32.0%, 98.7%). Additionally, the trial showed that the investigational vaccine was well-tolerated with no safety concerns, according to Pfizer.

The FDA previously granted RSVpreF with Breakthrough Therapy Designation for this indication in March 2022. The Prescription Drug User Fee Act date for a decision by the FDA on the BLA was set for May 2023.

Reference

U.S. FDA Accepts for Priority Review the Biologics License Application for Pfizer’s Respiratory Syncytial Virus Vaccine Candidate for the Prevention of RSV Disease in Older Adults. Pfizer. News release. December 8, 2022. https://www.pfizer.com/news/press-release/press-release-detail/us-fda-accepts-priority-review-biologics-license-0