Regulatory submissions based on the phase 3 data are anticipated in the second half of 2022.
Consistent high vaccine efficacy across endpoints
RSV is a common contagious virus affecting lungs and breathing passages: and is one of the remaining infectious diseases for which there is currently no vaccine or specific treatment available for adults. Older adults are at high risk for severe disease due to age-related decline in immunity and underlying conditions.
However, a number of candidates are now in late-stage clinical trials alongside GSK’s vaccine: including Moderna’s mRNA vaccine and Pfizer’s candidate.
Earlier this year GSK halted its Phase 3 maternal RSV vaccine trial, but remained committed to the vaccine program for older adults.
This candidate contains a recombinant subunit prefusion RSV F glycoprotein antigen (RSVPreF3) combined with GSK’s proprietary AS01E adjuvant.
The Phase 3 trial (AReSVi-006) was a randomized, placebo-controlled, observer-blind, multi-country trial to demonstrate the efficacy of a single dose of GSK's adjuvanted RSVPreF3 OA investigational vaccine in adults aged 60 years and above. Approximately 25,000 participants were enrolled from 17 countries.
In data released on Thursday, GSK reported the overall vaccine efficacy of 82.6% meant the vaccine met the trial’s primary endpoint; while ‘consistent high vaccine efficacy’ was also seen across secondary endpoints such as in participants with pre-existing comorbidities and older adults in the 70+ bracket. Vaccine efficacy against LRTD was consistent across both RSV-A and RSV-B subtypes.
The vaccine was well tolerated with a favorable safety profile.
In August, Pfizer announced efficacy of 85.7% for its vaccine in participants aged 60+ with more severe disease primary endpoint of lower respiratory tract illness (LRTI-RSV).
Moderna’s mRNA candidate mRNA-1345 entered Phase 3 trials for adults aged 60+ in February, with the FDA having granted Fast Track designation for the vaccine.
Tony Wood, GSK Chief Scientific Officer, said: “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.
"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.”
A longer-term program will continue to evaluate the vaccine with an annual revaccination schedule over multiple seasons.
