GSK secures expanded Japanese approval for Arexvy vaccine to cover at-risk adults under 50

GSK (NYSE:GSK) announced that Japan's Ministry of Health, Labour and Welfare (MHLW) has approved a label expansion for Arexvy, its adjuvanted recombinant respiratory syncytial virus (RSV) vaccine.

The regulatory milestone extends the eligible immunization pool to include adults aged 18 to 49 who are at an increased risk for RSV disease.

Prior to this decision, the vaccine was authorized in Japan for all individuals aged 60 and older, as well as at-risk individuals aged 50 to 59.

In tandem with the population expansion, the prescribing information has been updated to explicitly identify immunocompromised patients within the high-risk classification category.

The update is intended to assist medical clinicians in identifying candidates who may benefit from preventative vaccination.

Respiratory syncytial virus is highly contagious and poses acute risks to adults with underlying chronic conditions—such as cardiovascular disease, asthma, and chronic obstructive pulmonary disease (COPD)—where infections can trigger severe cardiac events, hospitalizations, or fatal outcomes.

Japan contains more than 42 million residents within the 18 to 49 age bracket, a cohort where chronic comorbidities frequently complicate standard respiratory infections.

The MHLW approval was granted based on data from a Phase IIIb clinical trial, which demonstrated a non-inferior immune response in at-risk adults between 18 and 49 years of age when evaluated against the established baseline of adults aged 60 and older.

The vaccine's clinical efficacy was validated in previous Phase III clinical testing, and its baseline safety profile remained consistent with historical findings across the broader developmental program.

Furthermore, the inclusion of immunocompromised patients in the updated prescribing material was supported by dedicated Phase IIb trial metrics evaluated by Japan's Pharmaceuticals and Medical Devices Agency (PMDA).