Moderna’s mRESVIA (mRNA-1345) has become the first mRNA-based vaccine for respiratory syncytial virus (RSV) to receive FDA approval. The vaccine is indicated for the prevention of lower respiratory tract disease caused by RSV infection in adults aged 60 years and older. This milestone marks Moderna’s second FDA-approved product after its COVID-19 vaccine.
Earlier this year, William Blair analysts noted the vaccine’s peak U.S. sales estimate of $1.46 billion is lower than the $1.5 billion and $890 million from GSK’s and Pfizer’s RSV vaccines respectively in 2023, early in their launch cycles.
Moderna’s approval of mRESVIA is based on the results of the randomized, double-blind, placebo-controlled phase 2/3 ConquerRSV trial involving 35,541 adults aged 60 or older. The study showed that a single 50 μg dose of mRNA-1345 demonstrated 83.7% efficacy against RSV-associated lower respiratory tract disease with at least two signs or symptoms and 82.4% efficacy against the disease with at least three signs or symptoms. The vaccine was effective against both RSV subtypes (A and B) and provided consistent protection across age and coexisting condition subgroups.
While the vaccine group experienced a higher incidence of local and systemic adverse reactions compared to the placebo group [(58.7% vs. 16.2%) and systemic adverse reactions (47.7% vs. 32.9%) in the vaccine group compared to placebo], most of these reactions were mild to moderate and transient. The occurrence of serious adverse events was similar in both groups (2.8%).
mRESVIA’s approval expands the options for protecting older adults against RSV, complementing the two previously approved protein-based vaccines from GSK and Pfizer. Notably, mRESVIA is the only RSV vaccine available in a single-dose pre-filled syringe, which is designed to maximize ease of administration and reduce the demands on vaccinators’ time.
As of May 2024, the CDC has not expressed a preferential recommendation between the available RSV vaccines for adults aged 60 and above. Moderna has submitted marketing authorization applications for mRNA-1345 to regulators around the world, aiming to make this innovative vaccine accessible to a broader population.
Comparison of FDA-approved RSV vaccines
| Feature | mRNA-1345 (Moderna) | RSVpreF/ABRYSVO (Pfizer) | Arexvy (GSK) |
|---|---|---|---|
| Study Population | Adults 60 years and older | Pregnant individuals and adults 60 years and older | Adults 60 years and older |
| Number of Participants | 35,541 | 7,400 pregnant individuals, 14,000 total participants | 25,000 |
| Pivotal Clinical Trial Name | ConquerRSV | MATISSE, RENOIR | AReSVi-006 |
| Efficacy Against RSV-LRTD | 83.7% (≥2 symptoms), 82.4% (≥3 symptoms) | 81.8% (severe MA-LRTI, 90 days), 69.4% (severe MA-LRTI, 6 months); 67.2% against LRTD in older adults | 82.6% against RSV-LRTD, 94.1% against severe LRTD over one season |
| Efficacy Over Multiple Seasons | Not specified | Maintained at 67.2% against LRTD over two seasons | Maintained at 76.8% against RSV-LRTD and 94.1% against severe LRTD over two seasons |
| Efficacy in High-Risk Groups | Effective in general older adult population | Effective in general older adult population and pregnant individuals’ infants | 94.6% efficacy in participants with comorbidities; 93.8% in adults aged 70-79 years |
| Safety Profile | Higher incidence of local (58.7% vs. 16.2%) and systemic (47.7% vs. 32.9%) adverse reactions compared to placebo; serious adverse events in 2.8% (both groups) | Similar risk of serious adverse events between vaccine group (4.3%) and placebo (4.1%); slightly higher severe reactogenicity (1.0% vs. 0.7%); 3 inflammatory neurologic events in vaccine group | Generally well tolerated; most frequent adverse events were injection site pain (60.9%), fatigue (33.6%), myalgia, headache and arthralgia (mild to moderate, transient) |
| Regulatory Status | Approved by FDA (2024) | Approved by FDA (2023) for maternal immunization and older adults | Approved by FDA (2023), European Commission, Japan and other regions |
Filed Under: Infectious Disease
