GSK plc (LSE/NYSE: GSK) announced new preliminary data for Arexvy (respiratory syncytial virus vaccine, recombinant adjuvanted) in adults aged 18-49 at increased risk for RSV-LRTD due to certain underlying medical conditions and in adults who are immunocompromised. These data show the vaccine’s potential to help protect a broader group of adults at risk from the potentially serious consequences of RSV. In the US alone, the number of adults aged 18-49 with at least one risk factor that could put them at risk for RSV disease could exceed 21 million.¹

The vaccine is currently approved for use in adults aged 60 and above in over 50 countries, and in adults aged 50-59 at increased risk in a number of countries including the US and Europe*. There are currently no RSV vaccines recommended for adults younger than 60 years of age who are at increased risk for RSV disease, despite the burden of disease in this population.

Tony Wood, Chief Scientific Officer, GSK, said: “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. 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.”

In the phase IIIb trial (NCT06389487²) a single dose of the vaccine elicited robust immune responses in adults aged 18-49 at increased risk for RSV-LRTD due to certain underlying medical conditions (n=395). The immune response was non-inferior to that observed in adults aged 60 and above (n=417), meeting the trial’s co-primary endpoints.

In the phase IIb trial (NCT05921903³) a single dose of the vaccine showed a robust immune response in adults aged 18 and above who are immunocompromised due to kidney or lung transplant (n=131), with a second dose (n=130) eliciting responses similar to those of healthy adults aged 50 and older who received one dose (n=125). These immune responses were consistent for RSV-A and RSV-B subtypes in all groups (those who received 1 or 2 doses). These data will be presented today at the meeting of the CDC’s Advisory Committee on Immunization Practices.

In both studies, the safety and reactogenicity data were consistent with results from the phase III programme that have supported the initial approval of the vaccine. The most common local adverse event was pain, and most common systematic adverse events were fatigue, myalgia, arthralgia and headache, most of which were transient and mild in intensity.

RSV is a common, contagious virus that can cause severe respiratory illness and impacts an estimated 64 million people of all ages globally every year.⁴ Immunocompromised people and those with certain underlying medical conditions, such as chronic obstructive pulmonary disease (COPD), asthma, heart failure and diabetes are at increased risk for severe consequences from an RSV infection compared to those without these conditions,^5,6 including having a higher risk of mortality.⁷

Final results from these trials will be presented at upcoming medical conferences and submitted for peer-reviewed publication. The final data will also be submitted to the US Food and Drug Administration (FDA) and other regulators to support potential label updates.