New Data for Arexvy Show Vaccine Efficacy Through 3 RSV Seasons in Older Adults

A single dose of the GSK vaccine Arexvy against respiratory syncytial virus (RSV) showed positive safety and efficacy data for protection over 3 RSV seasons for adults aged 60 years and older, including those at increased risk of severe disease, according to a company announcement.¹

The RSV vaccine, recombinant adjuvanted, was associated with a cumulative vaccine efficacy (VE) during season 3 of 62.9% against RSV-lower respiratory tract disease (LRTD) and 67.4% against severe RSV-LRTD, the company said. In the third season, VE was 48% against RSV-LRTD. The reported findings include VE against the RSV A and B subtypes, in elderly adults (aged 70 to 79 years), and those with underlying medical conditions that place them at high risk for adverse disease outcomes.¹

The data, from the AReSVi-006 (Adult Respiratory Syncytial Virus) phase III trial, are being presented at the CHEST 2024 Annual Meeting in Boston, MA, October 6-9.

“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,” Tony Wood, GSK chief scientific officer, said in the announcement.¹

The potential for RSV to exacerbate medical conditions and to lead to hospitalization for older adults underscores the value of the cumulative efficacy observed over 3 RSV seasons, GSK noted in the news release. The efficacy also "has the potential to offer health care professionals flexibility to administer the vaccine year-round," the company added. Currently the Advisory Committee on Immunization Practices (ACIP) recommends a single lifetime dose of an RSV vaccine is all adults aged 75 years and older and for adults aged 60 to 74 years at increased risk for severe RSV-LRTD.²

In August 2024, when the ACIP released its updated recommendation the committee noted that it will continue to review data on RSV vaccine safety, efficacy, and the duration of protection. Based on forthcoming evidence, ACIP may adjust its recommendations, particularly as they relate to revaccination and expansion of its vaccination recommendation to other populations.²

World's first RSV vaccine

Arexvy was approved as the world's first vaccine against RSV for adults aged 60 years and older in May 2023 based on data from the pivotal phase 3 AReSVi-006 trial.³ In the trial, which treated 25 000 participants with RSVPreF3 +AS01E and 25 000 with placebo, the vaccine showed statistically significant and clinically meaningful overall efficacy of 82.6% against RSV-LRTD in adults aged 60 years and older, satisfying the study’s primary endpoint. Further, efficacy was 94.6% in older adults with at least one underlying medical condition, such as certain cardiorespiratory and endocrine-metabolic conditions.³

A range of prespecified secondary endpoints for the trial also were consistently positive including efficacy of 94.1% in participants patients with severe RSV-LRTD, and 93.8% in adults aged 70-79 years. Efficacy was consistent across RSV A and B subtypes (84.6% and 80.9%, respectively), findings consistent with the significant neutralizing antibody response seen against both variants, according to the company.

The vaccine was generally well tolerated with the most commonly reported adverse events being injection site reaction, myalgias, headache, and arthralgias, all of which were mild-to-moderate in intensity and transient, according to an earlier GSK announcement.³ Data from the 3-year evaluation did not suggest any new adverse events.

References
1. GSK presents positive data for Arexvy, its respiratory syncytial virus (RSV) vaccine, indicating protection over three RSV seasons. News release. GSK. October 8, 2024. Accessed October 9, 2024. https://www.gsk.com/media/11611/press-release-gsk-rsv-s3-data.pdf
2. Steinzor P. ACIP recommendations for RSV vaccines in older adults: Update August 2024. Patient Care. August 8, 2024. https://www.patientcareonline.com/view/acip-recommendations-for-rsv-vaccines-in-older-adults-update-august-2024
3. Halsey G. FDA approves world's first vaccine against respiratory syncytial virus. Patient Care. May 3, 2023. https://www.patientcareonline.com/view/fda-approves-world-s-first-vaccine-against-respiratory-syncytial-virus