GSK has announced promising results for Arexvy, its respiratory syncytial virus (RSV) vaccine, showing a cumulative efficacy of 62.9% against RSV-related lower respiratory tract disease (RSV-LRTD) over three full RSV seasons in adults aged 60 years and older. This vaccine is the only one with efficacy and safety data available through three full seasons, including in individuals at increased risk due to underlying medical conditions.1
The findings were presented at the CHEST 2024 Annual Meeting, indicating 67.4% efficacy against severe RSV-LRTD. In the third season, the vaccine's efficacy was 48% against RSV-LRTD (95% CI, 8.7-72). The safety profile is consistent with previous phase 3 results, where the most frequently reported side effects included injection site pain, fatigue, myalgia, headache, and arthralgia within four days of vaccination.1
Summary of Key Findings
Cumulative Efficacy: 62.9% against RSV-LRTD over three seasons, with 48 cases in the vaccinated group compared to 215 in the placebo group.
Seasonal Efficacies:
Season One: 82.6% efficacy (7 of 12,466 vs 40 of 12,494).
Season Two: 56.1% efficacy (20 of 4,991 vs 91 of 10,031)
Season Three: 48% efficacy (16 of 4,988 vs 61 of 10,031).
Efficacy Against Severe Disease: 67.4% efficacy against severe RSV-LRTD over three seasons.
Season One: 94.1% (1 of 12,466 vs 17 of 12,494).
Season Two: 64.2% (5 of 4,991 vs 28 of 10,031).
Season Three: 43.3% (6 of 4,988 vs 21 of 10,031).
Efficacy in Participants with Comorbidities: Among participants with at least one pre-existing comorbidity, efficacy was 94.6% in the first season and 64.7% over three seasons.
GSK plans to continue providing long-term efficacy and immune response data to help inform revaccination schedules. RSV impacts an estimated 64 million people globally each year and can lead to severe outcomes, causing over 465,000 hospitalizations and 33,000 deaths annually among adults aged 60 and older in high-income countries.1
Tony Wood, chief scientific officer at GSK, said: “We are excited by these new data which show that a single dose of Arexvy could help protect millions of older adults at risk of RSV disease over three seasons to benefit public health. This is the only RSV vaccine with efficacy and safety data available through three full seasons. We will continue to provide data on longer term follow-up to help recommending bodies determine future revaccination schedules.”1
Arexvy was approved by the FDA in May 2023 for preventing RSV-LRTD in individuals aged 60 and older. Since then, it has received approvals in 50 countries, including Europe and Japan.1 This approval was based on the US phase 3 trial data that showed 82.6% efficacy against RSV related lower respiratory tract disease and 94.6% efficacy in patients with comorbidities. Arexvy combines the preF fusion protein with the AS01 adjuvant to enhance immune response in aging populations.2
The ongoing research aims to provide further insights into the vaccine's long-term effectiveness and the necessity for potential revaccination.
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