FDA to Review GSK's Application for Expanded Use of RSV Vaccine in High-Risk Adults Aged 18 to 49
GSK's RSV vaccine Arexvy would join shots from Pfizer and Moderna for the younger adult population, broadening choice for those with risk factors for severe disease.
The FDA has accepted GSK’s application to expand the indication of its vaccine against respiratory syncytial virus (RSV), Arexvy, to adults aged 18–49 who are at increased risk for lower respiratory tract disease (LRTD) caused by the infection. A regulatory decision is expected in the first half of 2026, according to a July 14 statement from GSK.1
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Arexvy is currently approved in the US for adults aged 60 and older,2 and for those aged 50–59 who are at elevated risk for RSV-related LRTD.3 If approved, the expanded indication would broaden access to protection against RSV in this younger high-risk population, with Arexvy joining vaccines from Moderna (mRSEVIA) and Pfizer (Abyrsvo) in the age group.
More than 125 million adults in the US are under age 50, and an estimated 21 million of them have at least one risk factor associated with heightened risk for RSV complications, ie, chronic obstructive pulmonary disease (COPD), asthma, congestive heart failure, and coronary heart disease.
The FDA submission is supported by data from a phase IIIb trial (NCT06389487) that evaluated immune response and safety in 18–49-year-old adults with at least 1 risk factor, compared to adults aged 60 and older. The trial enrolled 1,458 participants across 52 sites, including 16 in the US. Of these, 426 younger at-risk adults and 429 older adults were included in the immunogenicity cohort, while an additional 603 younger participants were followed for adverse events. The co-primary endpoints were RSV-A and RSV-B neutralization titers, assessed by geometric mean titer ratios and seroresponse rates one month post-vaccination. Investigators also evaluated safety and immunogenicity endpoints, GSK said.
The immune response in the younger at-risk adults was non-inferior to that observed in the older cohort, and the safety and reactogenicity profile was consistent with earlier phase III data that supported initial licensure of RSVPreF3. In prior trials, the most common adverse events in adults aged 50–59 included injection site pain (75.8%), fatigue (39.8%), myalgia (35.6%), headache (31.7%), arthralgia (23.4%), erythema (13.2%), and swelling (10.4%). The most frequent events in adults aged 60 and older were similar but slightly lower in frequency.
GSK has noted postmarketing data suggesting an increased risk of Guillain-Barré syndrome within 42 days of receiving Arexvy, and clinicians are advised to remain vigilant for neurologic symptoms following vaccination. The vaccine is contraindicated in individuals with a history of severe allergic reaction to any of its components, and syncope has been reported following administration.
If approved, this expanded indication would offer physicians a new preventive option for younger adults with chronic cardiopulmonary or immunocompromising conditions. Identification and vaccination of eligible patients could play a role in reducing RSV-related morbidity in this large and often overlooked at-risk population, the company said.
