Moderna's mRNA RSV vaccine delivers impressive Phase 3 trial results
Biotechnology company Moderna has announced promising results from its massive Phase 3 trial testing an mRNA vaccine for respiratory syncytial virus (RSV) in older adults. The data indicates the vaccine is nearly 84% effective at preventing moderate disease and the company expects to file for US Food and Drug Administration (FDA) approval this year.
RSV infection can turn into a deadly respiratory disease for both the very young and very old. For over half a century researchers have been trying to develop an effective vaccine and it looks like 2023 will be the landmark year where not only one, but possibly three different vaccines are finally approved.
Last year, pharma companies GSK and Pfizer both announced preliminary Phase 3 data for their RSV vaccine candidates. Both were focusing on disease in adults over the age of 60, and the successful results indicate the vaccines were between 60% and 80% effective at preventing lower respiratory symptoms.
Both GSK and Pfizer's RSV vaccines use a more traditional protein-based technology. Certain viral protein fragments are engineered and grown in lab conditions before being prepared and administered directly to individuals. Moderna's RSV vaccine, on the other hand, utilizes the recent mRNA technology that was first widely used in 2020 COVID-19 vaccines.
Moderna's RSV vaccine is the second mRNA vaccine to show positive Phase 3 trial data after the company accelerated its clinical research following the success of its COVID vaccines in 2020. This Phase 3 trial spanned 22 countries and enrolled around 37,000 adults.
"The study met the pre-defined statistical criteria for efficacy, with a vaccine efficacy of 83.7% against RSV-associated lower respiratory tract disease defined by 2 or more symptoms, and 82.4% against RSV-associated lower respiratory tract disease defined by 3 or more symptoms," reported Moderna's CEO Stephane Bancel in a recent blog post.
Over the next 12 months we will likely see all three RSV vaccines reach clinical use, battling for a slice of the multi-billion dollar market. Comparing different Phase 3 clinical trial results is not that useful, but preliminary announcements suggest GSK and Moderna are reporting relatively similar efficacy data, while Pfizer's candidate is just slightly behind.
What this means for real-world efficacy is unclear. RSV vaccines from Pfizer and GSK are already under evaluation from the FDA, with decisions expected by May. Moderna has indicated it will be submitting an application for its RSV vaccine over the coming months so it shouldn't be too far behind.
Moving forward, an initial approval for older adults is only the first step in RSV vaccine development, with pediatric and maternal trials currently underway from all three pharma companies. Moderna is also investigating a variety of novel mRNA vaccine formulations that roll its RSV vaccine into a single shot with antigens for SARS-CoV-2, influenza and human metapneumovirus (hMPV).