The US Food and Drug Administration (FDA) has expanded approval for Pfizer’s respiratory syncytial virus (RSV) vaccine, Abrysvo, to include adults aged 18–59 years who are at higher risk of lower respiratory tract disease from the virus due to chronic conditions.
weyo/Adobe Stock
This adds to the existing approvals for adults over 60 and pregnant women between 32 and 36 weeks gestation, as well as being ahead of the current RSV season in the US, between October and April.
In the final quarter of last year, Abrysvo generated $515m in sales, as per Pfizer’s financials. Although it’s far from Pfizer’s Covid-19 vaccine or Paxlovid sales at their peak, with declining demand for Covid-related products, Pfizer has identified Abrysvo as a primary future revenue driver.
The FDA's latest approval is based on positive data from the Phase III MONeT study (NCT05842967), which included patients with chronic conditions like asthma and diabetes (substudy A), as well as immunocompromised individuals (substudy B).
Pfizer has not released detailed results from the trial, but reported that a single 120µg dose produced a strong immune response against RSV-A and RSV-B.
In August, the company reported that a single 120µg dose of the vaccine led to “strong neutralising” responses against RSV-A and RSV-B. The commonly reported side effects included pain at the injection site, muscle pain, joint pain and nausea.
Pfizer is also evaluating Abrysvo in children aged between two and 17 years in an open-label Phase I PICASSO trial (NCT05900154). The trial enrolled 128 participants across the US.