FDA Approves Moderna’s RSV Vaccine

The FDA has approved Moderna’s mRESVIA (mRNA-1345), an mRNA respiratory syncytial virus (RSV) vaccine, to protect adults aged 60 years and older from lower respiratory tract disease caused by RSV infection. The approval was granted under a breakthrough therapy designation.

RSV is a common virus that can lead to potentially serious respiratory illness. Older adults, including those with underlying medical conditions such as diabetes and chronic heart and lung disease, are at increased risk of severe RSV illness and drive the majority of RSV hospitalizations. About 177,000 adults 65 years and older are hospitalized in the United States because of RSV.

mRESVIA consists of a single mRNA sequence encoding for a stabilized prefusion F glycoprotein. The vaccine uses the same lipid nanoparticles as in the Moderna COVID-19 vaccines. It will be available for the 2024/2025 RSV season as a pre-filled, ready to use syringe.

The FDA's approval of mRESVIA is based on positive data from the phase 3 clinical trial ConquerRSV, a global study conducted in approximately 37,000 adults ages 60 years or older in 22 countries. The study met its primary endpoint against RSV-associated lower-respiratory tract disease, with vaccine efficacy of 83.7% in those with two or more symptoms and vaccine efficacy of 82.4% in those with three or more symptoms. These results were published in December 2023 in The New England Journal of Medicine.

A follow-up analysis of the primary endpoint was performed during FDA review, including cases that started before the primary analysis cut-off date but were not confirmed until afterward. The results were consistent with the primary analysis. An additional longer-term analysis showed continued protection against RSV LRTD over 8.6 months median follow-up.

The most commonly reported solicited adverse reactions were injection site pain, fatigue, headache, myalgia and arthralgia.

Company officials said earlier this year that in addition to the United States, if other authorizations could follow and the company plans to launch the RSV vaccine in Australia and Germany this year and in other markets in 2025.

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Last year, the first two vaccines for RSV were approved for older adults and a separate vaccine was approved to prevent RSV infections in infants. GSK’s Arexvy, approved for adults in early May 2023, is an adjuvanted vaccine, which means it contains an ingredient to increase immune response. Arexvy is under review at the FDA to be used to prevent RSV in adults aged 50 to 59 who are at increased risk. The PDUFA date is June 7, 2024.

The second adult vaccine was approved a few weeks later. Pfizer’s Abrysvo is a bivalent RSV prefusion F (preF) vaccine that is composed of two preF proteins selected to optimize protection against RSV A and B strains. The FDA also approved Abrysvo to prevent RSV in infants.

Additionally, the FDA approved last year Sanofi and AstraZeneca’s Beyfortus (nirsevimab-alip), which prevents RSV in newborns and infants. Beyfortus is the first monoclonal antibody to protect infants through their first RSV season. Although designed to prevent disease like a vaccine, it is not a vaccine because it does not stimulate the immune system.