Pfizer RSV Vaccine Approved by FDA for Expanded Use in Ages 18-59

On October 22, Pfizer announced that the FDA has approved its bivalent respiratory syncytial virus (RSV) vaccine, Abrysvo, for the prevention of lower respiratory tract disease (LRTD) caused by RSV in high-risk populations aged 18 to 59 years. The vaccine was first approved for use in the U.S. in May 2023 for the prevention of RSV infections in individuals aged 60 and older. In August of the same year, the vaccine expanded its target population to include pregnant women to prevent RSV infections in infants from birth to 6 months old.

This approval is based on the pivotal Phase III MONeT study (NCT05842967), which evaluated the safety, tolerability, and immunogenicity of Abrysvo in high-risk adult populations for RSV infection. The results indicated that the study met its primary endpoint. Abrysvo demonstrated non-inferior neutralizing responses against RSV-A and RSV-B compared to its levels in the Phase III RENOIR study. One month after vaccination with Abrysvo, the serum neutralization titers for RSV-A and RSV-B in participants increased at least fourfold compared to pre-vaccination levels. During the trial, Abrysvo was well-tolerated, and safety results were consistent with previous studies.

This approval further expands the target population for Abrysvo. Compared to the already marketed RSV vaccines from GSK and Moderna, Abrysvo has a broader target population. GSK's Arexvy is now approved for individuals aged 50 and older, while Moderna's mRESVIA is approved for those aged 60 and older. Aamir Malik, Pfizer's Chief Commercial Officer and Executive Vice President, stated, “RSV poses a significant threat to certain young adults with chronic diseases. After decades of vaccine research by the scientific community and Pfizer, we now have the opportunity to help alleviate the RSV burden in this high-risk adult population. With this approval, the indications for Abrysvo have been expanded to include those in the elderly and pregnant populations, and we are proud to announce that Abrysvo is now the only RSV vaccine targeting adults aged 18 to 49 who are at increased risk for the disease.”

Highlights

• The FDA approved Pfizer's RSV vaccine, Abrysvo, for high-risk adults aged 18-59 on October 22.
• Abrysvo was previously approved for individuals aged 60 and older and for pregnant women to protect infants from RSV.
• The approval is based on the Phase III MONeT study, which showed positive safety and immunogenicity results.
• Abrysvo demonstrated a fourfold increase in neutralizing responses against RSV-A and RSV-B post-vaccination.
• This vaccine expands the target population compared to GSK's and Moderna's RSV vaccines, which have older age limits.
• Pfizer's Chief Commercial Officer emphasized the importance of addressing RSV in high-risk young adults with chronic diseases.