Biopharmaceutical company GSK plc (LSE: GSK) (NYSE: GSK) disclosed on Monday that Japan's Ministry of Health, Labour and Welfare has expanded approval for its RSV vaccine, Arexvy, to include adults aged 18 to 49 years who are at increased risk of respiratory syncytial virus disease.

The vaccine was previously approved in Japan for all adults aged 60 years and older and adults aged 50-59 at increased risk. Updated prescribing information now also explicitly identifies immunocompromised patients as an at-risk group eligible for vaccination.

GSK said the approval makes Arexvy the first RSV vaccine approved in Japan for adults aged 18-59 years at increased risk, as well as for all adults aged 60 years and older.

The expanded approval was supported by Phase IIIb trial data showing a non-inferior immune response in at-risk adults aged 18-49 compared with adults aged 60 years and above. Safety findings were consistent with previous Phase III studies, with the most common side effects including injection site pain, fatigue, headache and muscle pain.

GSK said millions of adults in Japan aged 18-49 live with chronic conditions that increase the risk of severe RSV outcomes, including cardiovascular complications, chronic obstructive pulmonary disease and asthma exacerbations.

The company continues to pursue additional regulatory submissions for Arexvy globally to broaden access to RSV prevention.