Arexvy approved for individuals 60 years of age and older.
What is Respiratory Syncytial Virus and why does it matter?
The human respiratory syncytial virus (RSV) [1] is one of the most common viruses to infect children worldwide and increasingly is recognized as an important pathogen in the elderly. RSV is a single, negative-stranded, RNA virus belonging to the Paramyxoviridae family, causing upper respiratory infection, though frequently present in young children as bronchiolitis with small airway obstruction. In the young population, it rarely progresses to respiratory failure or death.
However, in the elderly population and those with underlying comorbidities [2], it carries a significant risk of hospitalization and other co-infections. A recent systematic review [2] published in 2023 indicated that the median proportion of elderly patients with RSV in all adult patients with an acute respiratory infection (ARI) or community-acquired pneumonia was 79.78% in Japan, 48.00% in China, 41.67% in Taiwan, 28.57% in South Korea, and 38.61% in Australia. It is a major source of disease burden among elderly patients, especially in ageing countries.
Approval of Arexvy – The First Respiratory Syncytial Virus Vaccine
The good news is, on the 3rd of May, the FDA [3] approved Arexvy – the first RSV vaccine for use in the United States in individuals 60 years of age and older. The approval is based on the positive findings in the AReSVi-006 (Adult Respiratory Syncytial Virus) phase III trial [4]. The trial randomly assigned 24,966 adults over 60 years old in a 1:1 ratio to either receive a single dose of an AS01E-adjuvanted RSV prefusion F protein-based candidate vaccine (RSVPreF3 OA) or a placebo before the RSV season.
Efficacy Data of RSV Vaccine in Phase 3 Trial
In total, 47 participants (7 of 12,466 in the vaccine group and 40 of 12,494 in the placebo group) in the modified exposed population reported an episode of RSV-related lower respiratory tract disease during a median follow-up of 6.7 months.
Efficacy against severe RSV-related lower respiratory tract disease (assessed on the basis of clinical signs or by the investigator) was 94.1% (95% CI, 62.4 to 99.9), with 1 case in the vaccine group and 17 cases in the placebo group. A total of 122 participants (27 in the vaccine group and 95 in the placebo group) had at least one episode of RSV-related acute respiratory infection, resulting in a vaccine efficacy of 71.7% (95% CI, 56.2 to 82.3).
Adverse Events of RSV Vaccine in Phase 3 Trial
In terms of its safety [4], the RSVPreF3 OA vaccine was more reactogenic than the placebo, but most adverse events for which reports were solicited were transient, with mild-to-moderate severity. The reactogenicity–immunogenicity cohort included 1799 participants, of whom 1757 were part of the solicited safety population. In the solicited safety population, the pain was the most common injection-site reaction for which data were solicited (in 60.9% of the participants in the vaccine group and in 9.3% of those in the placebo group), and fatigue was the most common solicited systemic reaction (in 33.6% and 16.1%, respectively). Most mild to moderate side effects resolved within the 4-day period. 10 vaccine recipients (0.1%) and 7 placebo recipients (0.1%) had a serious adverse event that was considered by the investigator to be related to the vaccine or placebo (most common system organ class, nervous system disorders).
Phase 3 Trial Overall Findings
The trial [4] concluded that a single dose of the RSVPreF3 OA vaccine was efficacious against RSV-related lower respiratory tract disease, RSV-related acute respiratory infection, and severe RSV-related lower respiratory tract disease among adults 60 years of age or older during one RSV season, with an acceptable safety profile. Future trials could investigate its effectiveness and potential use in infants and children population, along with its safety profiles.
Reference:
- Schweitzer JW, Justice NA. Respiratory Syncytial Virus Infection (RSV) [Internet]. Nih.gov. StatPearls Publishing; 2018. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459215/
- Kurai D, Song J, Huang YC, Jie Z, Atanasov P, Jiang X, et al. Targeted Literature Review of the Burden of Respiratory Syncytial Infection among High-Risk and Elderly Patients in Asia Pacific Region. Infectious Diseases and Therapy. 2023 Mar;12(3):807–28.
- FDA Approves First Respiratory Syncytial Virus (RSV) Vaccine [Internet]. FDA. 2023. Available from: https://www.fda.gov/news-events/press-announcements/fda-approves-first-respiratory-syncytial-virus-rsv-vaccine
- Papi A, Ison MG, Langley JM, Lee DG, Leroux-Roels I, Martinon-Torres F, et al. Respiratory Syncytial Virus Prefusion F Protein Vaccine in Older Adults. New England Journal of Medicine. 2023 Feb 16;388(7):595–608.