The Food and Drug Administration (FDA) announced its vaccine advisers will meet on Feb. 28 and March 1 to discuss two experimental respiratory syncytial virus (RSV) vaccines under review for older adults. 

The Vaccines and Related Biological Products Advisory Committee will meet in open session on Feb. 28 to discuss and make recommendations on the safety and effectiveness of Pfizer’s Abrysvo before meeting on March 1 to discuss GSK’s Arexvy vaccine. Both companies are seeking approval for active immunization for the prevention of acute respiratory disease and lower respiratory tract disease (LRTD) caused by RSV in adults 60 years of age and older.

The meeting presentations will be heard, viewed, captioned, and recorded through an online teleconferencing platform. The FDA intends to make background material available to the public no later than two business days before the first meeting.

The FDA accepted Biologics License Applications and granted priority review for both Pfizer and GSK’s RSV older adult vaccine candidates late last year following positive data from phase 3 trials. 

According to a November press release from GSK, its phase 3 trial showed high overall vaccine efficacy against RSV LRTD in adults aged 60 years and older and that the vaccine was well tolerated with a favorable safety profile. The most frequently observed solicited adverse events were injection site pain, fatigue, myalgia, and headache. Consistent high vaccine efficacy was observed against LRTD in severe disease, adults aged 70-79 years, adults with underlying comorbidities, and across RSV A and B strains.

In a December press release, Pfizer said its regulatory submission was supported by results of its RENOIR trial, a global, randomized, double-blind, placebo-controlled study designed to assess the efficacy, immunogenicity, and safety of a single dose of RSV vaccine in adults 60 years of age and older. The trial enrolled approximately 37,000 participants as of December. 

Last August, Pfizer announced positive top-line results of an interim efficacy analysis for RENOIR. Vaccine efficacy of 85.7% was observed in participants with more severe disease primary endpoint of lower respiratory tract illness defined by analysis of three or more RSV-associated symptoms. The vaccine was well tolerated with no safety concerns, according to the company.

Adults at highest risk for severe RSV infection include older adults, especially those 65 years and older; adults with chronic heart or lung disease; and adults with weakened immune systems, according to the Centers for Disease Control and Prevention. Each year, it is estimated that between 60,000 and 120,000 older adults in the US are hospitalized, and between 6,000 and 10,000 of them die due to RSV infection.