Respiratory syncytial virus (RSV) vaccine Arexvy shows strong immune responses in adults aged 18-49 with an elevated risk for RSV lower respiratory tract disease, including immunocompromised adults, suggesting the potential to expand the vaccine's use beyond its current approval in older age groups.
A pair of clinical trials demonstrated that GSK’s respiratory syncytial virus (RSV) vaccine Arexvy produced a strong immune response in adults aged 18-49 years with an elevated risk for RSV lower respiratory tract disease (LRTD), including immunocompromised individuals. These findings could lead to expanded use for the vaccine that broadens protection beyond its current indications in those 60 years of age and above and in adults aged 50-59 with an increased risk of RSV-LRTD.1-3
“These promising data add to the evidence supporting GSK’s RSV vaccine and could help expand protection to more adults at risk from RSV disease,” Tony Wood, chief scientific officer, GSK, said in a press release. “They also provide valuable insights into the potential impact of a second dose for certain populations. We’re committed to working with health authorities and regulators to help adults at increased risk of RSV disease benefit from vaccination.”1
RSV develops in 3% to 7% of healthy older adults in the United States and Europe annually, with an estimated 177,000 hospitalizations and 14,000 deaths each year in the United States alone. RSV can be especially severe in older adults, as approximately 18% of hospitalizations involve admission to an intensive care unit; 31% of individuals receive home health services at discharge; and 26% die within one year post admission. Among older adults, RSV is a common cause of LRTD, which affects the lungs and can cause life-threatening pneumonia and bronchiolitis. The CDC has found that RSV leads to approximately 60,000-120,000 annual hospitalizations and 6,000-10,000 annual deaths among adults 65 years of age and older.4
Arexvy contains a recombinant subunit prefusion RSV F glycoprotein antigen (RSVPreF3) combined with GSK’s proprietary AS01E adjuvant. In May 2023, Arexvy became the first FDA-approved RSV vaccine to prevent LRTD caused by RSV in individuals 60 years of age and older.4 The FDA approved an expanded indication for Arexvy in June 2024 for adults aged 50-59 years with an increased risk for RSV-LRTD.5
The latest trial results may lead to an expanded indication that covers a wider population with an elevated risk of severe disease.
A Phase IIIb open label trial (NCT06389487) is analyzing Arexvy for non-inferiority of immune response and safety among 1457 participants aged 18-49 years with an increased risk of RSV disease (n=395) compared to individuals aged 60 years and above (n=417).2 The analysis included an additional cohort of 601 individuals aged 18-49 years who were followed to track adverse events separate from the safety follow up of the initial cohort. This study is ongoing to track safety and immunogenicity for up to six months post vaccination and is expected to finish in 2025.
Preliminary data showed that a single dose of Arexvy produced robust immune responses in individuals 18-49 years of age with an increased risk of RSV-LRTD because of certain underlying medical conditions (n=395). The data show that the immune response was non-inferior to responses seen in adults 60 years of age and older (n=417), which was one of the trial’s co-primary endpoints.
A Phase IIb randomized, controlled, open-label, multi-country trial (NCT05921903) is evaluating the immune response and safety of Arexvy in individuals aged 18 years and above who are immunocompromised from lung and renal transplantation.3 The trial is comparing one dose of Arexvy (n=131) with two doses (n=130) one month (30-42 days) after administration of the second dose compared to a control cohort of non-immunocompromised individuals aged 50 years and older (n=125) administered a single dose of Arexvy.
Preliminary data found that a single dose of Arexvy produced a robust immune response in the cohort who are immunocompromised from kidney or lung transplantation (n=131). Further, a second dose of Arexvy produced (n=130) responses that are similar to what was observed in healthy individuals 50 years of age and older administered one dose of Arexvy (n=125).
Immune responses were found to be consistent across RSV-A and RSV-B subtypes in all cohorts. The ongoing trial will gather additional safety and immunogenicity data for up to 12 months post final dose, with completion expected in 2025.
GSK stated that these data will be presented at a meeting of the CDC Advisory Committee on Immunization Practices. They added that final results from the trials will be presented at upcoming medical conferences, submitted for peer-reviewed publication, and will be submitted to the FDA and other regulators to support potential expanded indications.
References
1. New data for Arexvy, GSK’s respiratory syncytial virus vaccine, show potential to help protect a broader group of adults at increased risk for RSV disease. News release. GSK. October 24, 2024. Accessed October 24, 2024. https://www.gsk.com/en-gb/media/press-releases/new-data-for-arexvy-show-potential-to-help-protect-a-broader-group-of-adults-at-increased-risk-for-rsv-disease/
2. A Study on the Immune Response and Safety of Vaccine Against Respiratory Syncytial Virus (RSV) Given to Adults 18 to 49 Years of Age at Increased Risk for Respiratory Syncytial Virus Disease, Compared to Older Adults 60 Years of Age and Above. ClinicalTrials.gov. Updated October 2, 2024. Accessed October 24, 2024. https://clinicaltrials.gov/study/NCT06389487
3. A Study on the Immune Response and Safety of an RSV Vaccine When Given to Adults 18 Years of Age and Above Who Received Lung or Kidney Transplant and Are at an Increased Risk of Respiratory Syncytial Virus Lower Respiratory Tract Disease and Compared to Healthy Adults 50 Years of Age and Above (RSV OA=ADJ-023). ClinicalTrials.gov. Updated May 22, 2024. Accessed October 24, 2024. https://clinicaltrials.gov/study/NCT05921903
4. FDA Approves First Respiratory Syncytial Virus (RSV) Vaccine. FDA. News release. May 3, 2023. Accessed October 24, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-first-respiratory-syncytial-virus-rsv-vaccine?utm_medium=email&utm_source=govdelivery.
5. US FDA approves expanded age indication for GSK’s Arexvy, the first respiratory syncytial virus (RSV) vaccine for adults aged 50-59 at increased risk. GSK. June 7, 2024. Accessed October 24, 2024. https://www.gsk.com/en-gb/media/press-releases/us-fda-approves-expanded-age-indication-for-gsk-s-arexvy-the-first-rsv-vaccine-for-adults-aged-50-59-at-increased-risk/
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