GlaxoSmithKline (GSK) has secured approval from Japan's Ministry of Health, Labour and Welfare (MHLW) to extend the indication of its respiratory syncytial virus (RSV) vaccine, Arexvy, to include adults aged 50 to 59 who are at increased risk of RSV infection. This decision broadens the vaccine's availability, which was initially approved for individuals aged 60 and above in September 2023.
The MHLW's decision is rooted in the outcomes of a Phase III clinical trial, which included four clinical sites in Japan. The trial demonstrated that Arexvy elicited non-inferior immunogenicity in the 50-59 age group when compared to the 60 and older cohort. Furthermore, the safety and reactogenicity profiles observed in the newly approved age group were consistent with those reported in the original Phase III program involving older adults.
Clinical Trial Data and Immunogenicity
The Phase III trial results indicated that adults aged 50-59 with underlying medical conditions achieved an immune response comparable to that of older adults. This finding is crucial as it supports the vaccine's effectiveness across a broader age range. The consistent safety profile further reinforces the vaccine's suitability for use in this expanded population.
RSV and At-Risk Populations
RSV is a common contagious virus affecting the lungs and breathing passages, impacting an estimated 64 million people of all ages globally each year. Adults with underlying medical conditions, compromised immune systems, or advanced age are at higher risk of severe RSV disease. RSV infection can exacerbate conditions such as COPD, asthma, and chronic heart failure, potentially leading to pneumonia, hospitalization, and even death.
Arexvy: Composition and Mechanism
Arexvy's active component is a recombinant RSV glycoprotein F stabilized in the prefusion conformation (RSVPreF3), combined with GSK's AS01E adjuvant system. The AS01E adjuvant includes STIMULON QS-21, licensed from Agenus' subsidiary, Antigenics. This formulation is designed to elicit a robust immune response, providing protection against RSV-related lower respiratory tract disease.
GSK's Perspective
GSK chief scientific officer Tony Wood stated, "This approval reflects our ambition to protect people at increased risk from the severe consequences of RSV infection. Adults aged 50 to 59 with certain underlying medical conditions can face debilitating consequences from RSV, so we are pleased to offer those in Japan a vaccine for the first time."
Global Approvals and Future Prospects
Prior to this approval in Japan, GSK secured approval for Arexvy in Canada for the prevention of lower respiratory tract disease caused by RSV in adults aged 50 to 59 at increased risk. The vaccine is now authorized in the US and 35 other countries, with regulatory decisions pending in other regions. This widespread approval underscores the global effort to combat RSV and protect vulnerable populations.
