GSK plans to advance its experimental seasonal mRNA influenza vaccine, FLUm3HA.b-3NA, into a Phase III efficacy trial beginning in September 2026.
The move follows the Phase II Flu-028 study, which enrolled 971 adults and found higher immune responses than licensed standard-dose vaccines in younger adults and high-dose vaccines in older adults. The candidate was generally well tolerated.
The vaccine is designed to target both haemagglutinin (HA), which helps the virus bind to cells, and neuraminidase (NA), which helps it spread. Most existing flu vaccines primarily target HA.
GSK says this dual-target strategy could improve protection, reduce illness severity and limit transmission, but these potential benefits still need to be demonstrated in Phase III efficacy testing.
If launched as planned, the study would be the first late-stage trial of an mRNA flu vaccine specifically designed to target both HA and NA. The candidate has also received FDA Fast Track designation.
Sources:
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