GSK announced positive real-world evidence from a large-scale observational study evaluating Arexvy (respiratory syncytial virus vaccine, adjuvanted) in adults aged 60 years and older. The study demonstrated that vaccination with the recombinant RSVPreF3 antigen vaccine was associated with a significant reduction in severe secondary outcomes, including myocardial infarction, stroke, and exacerbations of chronic obstructive pulmonary disease (COPD) and asthma following respiratory infection. These findings are significant for the industry as they provide evidence that preventing RSV infection may mitigate the risk of major adverse cardiovascular and respiratory events in vulnerable older populations.

Trial specifics

The real-world evidence was derived from a retrospective observational study using a large US-based claims database, encompassing more than 1 million vaccinated individuals compared to an unvaccinated cohort of similar size. The study was designed to assess the effectiveness of the vaccine against RSV-related clinical complications during the 2023-2024 RSV season. The primary focus of the analysis was the incidence of acute cardiovascular events and severe respiratory flares within a specific window following a confirmed or suspected RSV encounter. Researchers found that vaccinated individuals had a 42% lower risk of experiencing a heart attack and a 33% lower risk of stroke compared to the unvaccinated group. Furthermore, the data indicated a 41% reduction in the risk of severe COPD exacerbations and a 35% reduction in asthma flares requiring hospitalization or emergency intervention. The safety profile observed in this real-world setting remained consistent with the data previously reported in the pivotal Phase III AReSVi-006 trial, with no new safety signals identified across the large patient population.

GSK indicated that it will continue to monitor long-term data to further characterize the broader public health impact of RSV vaccination. Tony Wood, Chief Scientific Officer at GSK, stated that the data reinforce the importance of vaccination not only in preventing the primary respiratory infection but also in reducing the downstream burden of life-threatening cardiovascular and pulmonary complications. The company plans to present the full dataset at upcoming medical congresses and submit the findings to regulatory authorities to support potential updates to clinical guidelines. Arexvy is already approved by the US FDA for the prevention of RSV-lower respiratory tract disease in adults aged 60 and older and for those aged 50-59 at increased risk; however, these new data could influence broader adoption among specialists managing chronic cardiac and metabolic conditions.

Research context

Arexvy utilizes a recombinant subunit prefusion F protein (RSVPreF3) combined with the proprietary AS01E adjuvant system. The vaccine is designed to induce a robust immune response by targeting the F protein in its prefusion conformation, which is the primary target for neutralizing antibodies. This mechanism is critical because RSV infection is known to trigger systemic inflammation and significant physiological stress, which can lead to the rupture of atherosclerotic plaques or severe bronchoconstriction in patients with underlying chronic conditions. By preventing the initial viral infection and subsequent inflammatory cascade, the vaccine aims to protect patients from multi-systemic complications. Arexvy received its initial US FDA approval in May 2023, marking the first RSV vaccine authorized for older adults.

The RSV vaccine landscape has evolved rapidly into a highly competitive field involving several major pharmaceutical developers. Key competitors include:

  • Pfizer’s Abrysvo, a bivalent RSV prefusion F vaccine that is currently approved for older adults and pregnant individuals to protect infants, with ongoing Phase III studies to expand its use into younger high-risk adult populations.
  • Moderna’s mRESVIA, an mRNA-based vaccine (mRNA-1345) that recently received US FDA approval for adults aged 60 and older, representing the first non-protein subunit modality in this indication.
  • Sanofi and AstraZeneca’s nirsevimab, while not a vaccine, is a long-acting monoclonal antibody approved as a passive immunization strategy for the prevention of RSV-related disease in neonates and infants entering their first RSV season.
  • Merck & Co.’s clesrovimab, an investigational long-acting monoclonal antibody currently in Phase III development intended to provide extended protection for infants.