GSK RSV Vaccine Trial Demonstrates Promising Results

Respiratory Syncytial Virus under a microscope (Adobe Stock)

This article was first published on Contagion.com.

Last week, GlaxoSmithKline (GSK) reported positive data from a phase 3 trial for their respiratory syncytial virus (RSV) vaccine.

The RSV vaccine candidate reduced the incidence of lower respiratory infection in participants 60 years and older by 94.1%, with 82.6% overall vaccine efficacy, as compared to placebo. It proved effective in separate analyses of severity, age group, and comorbidity, reporting only mild side effects.

“We believe that with the high vaccine efficacy demonstrated in this pivotal trial, our vaccine candidate has the potential to help reduce the significant global burden of RSV-associated disease in older adults, including those at the greatest risk of severe outcomes due to their age or underlying comorbidities,” said Tony Wood, chief scientific officer of GSK.

Efficacy against severe RSV lower respiratory tract disease (RSV-LRTD), defined by at least 2 lower respiratory signs or otherwise assessed as severe, was 94.1%. Among participants with preexisting comorbidities, including cardiorespiratory or endocrinometabolic conditions, vaccine efficacy was 94.6%. For adults 70-79 years of age, vaccine efficacy was 93.8%.

This observed vaccine effectiveness was consistent for both RSV-A and RSV-B subtypes, with respective efficacies of 84.6% and 80.9%.

“These are truly exceptional results given that today RSV remains one of the major infectious diseases without a vaccine, despite over 60 years of research,” Wood said.

Developing an RSV vaccine has proven difficult, as investigators struggled to direct the body’s immune system against the virus’s specific protein. Notably, Pfizer, Johnson & Johnson, Moderna, Sanofi, and Bavarian Nordic are all testing RSV vaccines. So far, there are no approved RSV vaccines.

RSV is a common and contagious respiratory virus that attacks the lungs and breathing passageways. It is a major infectious disease for which there is no targeted treatment or vaccine for adults. Due to a natural age-related decline in immunity, older adults are at high risk of severe disease progression. In industrialized countries, RSV is responsible for an estimated 420,000 hospitalizations and 29,000 deaths.

GSK’s RSV vaccine candidate contains a recombinant subunit prefusion RSV F glycoprotein antigen (RSVPreF3), combined with the biopharma company’s proprietary AS01E adjuvant. The vaccine was well tolerated, with most reported side effects mild-to-moderate in severity.

The phase 3 study for the RSV vaccine candidate, AReSVi-006 (Adult Respiratory Syncytial Virus), is a randomized, placebo-controlled, observer-blind, multi-country clinical trial. The study evaluated the safety and efficacy of a single dose of the adjuvanted RSVPreF3 OA investigational vaccine. AReSVi-006 included approximately 25,000 adult participants across 17 countries.

Investigators will continue to analyze an annual revaccination schedule and long-term protection over multiple seasons following 1 dose of the RSV vaccine candidate.

GSK will present this and more data this week at the upcoming IDWeek 2022 Conference.