GSK has released new preliminary data showing that its respiratory syncytial virus (RSV) vaccine Arexvy met primary endpoints in a Phase III trial in adults aged 50 to 59 years.

The study also included adults who are at an increased RSV lower respiratory tract disease (LRTD) due to certain underlying medical conditions.

While the company did not share detailed results, it revealed that the Arexvy elicited an immune response in subjects with increased risk for RSV disease due to certain medical conditions.

The immune response was non-inferior to what was observed in the approved patient population of adults aged 60 and above, meeting the trial’s co-primary endpoint. This was also observed in the broader patient population of the trial.

Arexvy’s safety and reactogenicity data were consistent with the already established safety profile in the approved patient population. Pain was the most common local adverse event, with patients also reporting systematic adverse events such as fatigue and headache.

According to GSK, it is on track to be the first company to submit data on this patient population to regulators. GSK anticipates hearing back from regulatory agencies on their decision for potential label expansion in 2024.

The results were presented at the US Centers for Disease Control and Prevention’s (CDC) Advisory Committee on Immunization Practices (ACIP) meeting on 25 October 2023. GSK plans to present full data from the trial at an upcoming medical conference and submit it for peer-reviewed publication.

Arexvy was first approved by the US Food and Drug Administration (FDA) for adults aged 60 and above in May. Other regulatory agencies followed suit, and the vaccine is currently approved in Europe, Japan, the UK, and Canada. In June, the US Centers for Disease Control and Prevention (CDC) also backed GSK’s Arexvy, alongside Pfizer’s Abrysvo.

RSV landscape

RSV is a common and contagious virus that usually causes mild symptoms but can lead to severe respiratory illness.

In July, Moderna announced global regulatory submissions for its RSV vaccine MRNA-1345. The following month, a US-based biotech Meissa Vaccines reported positive data from its Phase I trial investigating intranasal vaccine MV-012-968 in a paediatric population.

However, not everyone is succeeding in the RSV space. In July, Bavarian Nordic shelved its MVA-BN RSV after the vaccine candidate failed to meet the co-primary endpoint of severe LRTD in a Phase III trial.

According to GlobalData’s Clinical Trial Database, there are 45 ongoing or planned Phase I-III trials investigating RSV vaccines. The majority of trials are in Phase I (35.6%), followed by Phase III trials (31.1%). GlobalData is the parent company of Clinical Trials Arena.