GSK Moves Dual-Target mRNA Influenza Vaccine into Pivotal Phase 3 Study

As the respiratory virus season draws near, GSK is preparing to launch a Phase 3 clinical trial for its experimental messenger RNA flu vaccine.

The company announced the pivotal study plans after disclosing Phase 2 data indicating that the vaccine elicited stronger immune responses against all influenza strains than currently available options. Results from both younger and older adult cohorts were unveiled on Tuesday at the OPTIONS XIII Conference for the Control of Influenza in Washington, D.C.

Existing flu vaccines trigger an immune response against hemagglutinin (HA), a surface protein that facilitates pathogen binding to cells. GSK notes that mounting evidence indicates targeting both HA and neuraminidase (NA)—a second protein—could enhance protection, reduce illness severity, and curb virus transmission. Their seasonal vaccine is a multivalent candidate addressing both HA and NA. GSK added that previous research underscored the necessity of improving the immune response to the influenza B strain’s HA protein, alongside the established role of NA in seasonal flu transmission.

The Phase 2 trial involved 971 adults and evaluated two comparable mRNA vaccines: FLUm3HA.b-3NA, which encodes an optimized B-strain HA, and FLUm3HA-3NA, which encodes a non-optimized B/HA. GSK reported that both vaccines generated robust immune responses to HA and NA from influenza A and B strains across both age demographics.

GSK characterized the vaccine’s safety profile and side effects as acceptable. Leveraging the Phase 2 findings, the company selected the optimized B-strain HA candidate for Phase 3 evaluation, with the pivotal trial slated to commence later this month.

“These promising data support the potential to better protect people from flu with a vaccine designed to target both HA and NA,” said Sanjay Gurunathan, GSK Head of Vaccines and Infectious Diseases Research and Development, in a prepared statement. “Given one billion flu cases and up to 650,000 deaths worldwide each year, there is a pressing need for next-generation vaccine approaches.”

The first mRNA vaccine for seasonal flu is heading to market after the FDA approved Moderna’s mFLUSIVA in August. Similar to current flu vaccines, Moderna’s offering targets only the HA protein.

GSK acquired its mRNA vaccine candidates from former partner CureVac in 2024 for €400 million (approximately $431.4 million) upfront. Following the acquisition, CureVac pivoted away from infectious disease vaccines to focus on cancer vaccines. CureVac subsequently became a subsidiary of BioNTech after a $1.25 billion all-stock acquisition last year.

Image by Flickr user quapan via a Creative Commons license

Source link