The US Food and Drug Administration (FDA) has approved Pfizer’s Abrysvo, a bivalent respiratory syncytial virus prefusion F (RSVpreF) vaccine, for the prevention of lower respiratory tract disease caused by RSV in individuals 60 years and older. 

Abrysvo is unadjuvanted and composed of two preF proteins selected to optimize protection against RSV A and B strains and was observed to be safe and effective.

“A vaccine to help prevent RSV had been an elusive public health goal for more than half a century. Today’s approval is a monumental step forward in delivering on Pfizer’s commitment to help alleviate the significant burden of RSV in higher-risk populations, which includes older adults,” says Annaliesa Anderson, PhD, senior vice president and chief scientific officer, vaccine research and development, Pfizer, in a release. “Abrysvo will address a need to help protect older adults against the potentially serious consequences of RSV disease. We are extremely grateful to the clinical trial participants, study investigator teams, and our dedicated Pfizer colleagues for their roles in making this vaccine available.”

The FDA’s decision is based on the data from the pivotal phase 3 clinical trial RENOIR (RSV vaccine Efficacy study iN Older adults Immunized against RSV disease). RENOIR is a global, randomized, double-blind, placebo-controlled study designed to assess the efficacy, immunogenicity, and safety of a single dose of the vaccine in adults 60 years of age and older. 

RENOIR has enrolled approximately 37,000 participants, randomized to receive RSVpreF 120 μg or placebo in a 1:1 ratio. The results were recently published in The New England Journal of Medicine. RENOIR is ongoing, with efficacy data being collected in the second RSV season in the study.

“This past RSV season demonstrated the serious consequences and potential health risks this virus poses for older adults,” says Edward E. Walsh, MD, professor of medicine, University of Rochester Medical Center, and principal RENOIR investigator, in a release. “Today’s FDA approval of Abrysvo recognizes significant scientific progress and, importantly, helps provide older adults potential protection against RSV and an opportunity to improve community health by helping prevent the disease.”

The US Centers for Disease Control and Prevention’s Advisory Committee on Immunization Practices will meet on June 21 to discuss recommendations for the appropriate use of RSV vaccines in older adults. Pending the outcome of this meeting, Pfizer anticipates supply availability in the third quarter of this year ahead of the anticipated RSV season this fall.

Pfizer also recently reported positive top-line results from the phase 3 study evaluating the safety and immunogenicity of Abrysvo coadministered with seasonal inactivated influenza vaccine in adults 65 years and older. Pfizer intends to publish these results in a peer-reviewed scientific journal. 

Additionally, Pfizer announced it would be initiating multiple clinical trials evaluating RSVpreF in healthy children ages 2-5; children ages 5-18 with underlying medical conditions; adults ages 18-60 at high risk due to underlying medical conditions; and adults ages 18 and older who are immunocompromised and at high-risk for RSV.8

The FDA granted Breakthrough Therapy Designation for Abrysvo in March 2022 for the prevention of lower respiratory tract disease caused by RSV in individuals 60 years of age and older. This decision was followed by the FDA’s acceptance of Abrysvo’s Biologics License Application under priority review for older adults in November 2022.

The decision follows the approval of the first RSV vaccine last month. In May, the FDA approved Arexvy (GlaxoSmithKline) for the prevention of lower respiratory tract disease caused by RSV in individuals 60 years of age and older.

Photo caption: Pfizer’s RSV vaccine vials

Photo credit: Pfizer