Results from the planned interim analysis showed that the multivalent vaccine candidate using CureVac’s proprietary second-generation mRNA backbone boosted antibody titers against all encoded flu strains and across all age groups and tested dose levels, including the lowest tested dose. The vaccine candidate was shown to have an acceptable safety and tolerability profile, with the majority of solicited adverse events reported as either grade 1 (mild) or grade 2 (moderate) within seven days of dosing. The results confirm previous findings that the platform elicits strong overall antibody titers at well-tolerated dose levels.

Among younger and older adults, geometric mean titers generated by the vaccine candidate against influenza A strains numerically exceeded the geometric mean titers of the licensed comparator vaccines consistently across all tested dose levels. For influenza B strains geometric mean titers were lower than those elicited by the licensed comparator vaccines across both age groups and tested dose levels. Targeted optimizations to further improve immune responses against influenza B strains will be tested in an additional Phase 2 study.

“The Phase 2 interim data show that CureVac’s highly effective and flexible mRNA technology platform puts us on the right track to advance our joint seasonal influenza vaccine program,” said Dr. Myriam Mendila, Chief Development Officer of CureVac. “Results regarding influenza A strains were strong. Immunogenicity for B strains was in line with our expectations also in view of other initial mRNA-based clinical flu development programs. We are confident that planned optimizations will improve performance against these historically challenging influenza strains.”

The Phase 2 dose-confirmation study assesses the reactogenicity, safety, and immunogenicity of different dose levels of a modified, multivalent vaccine candidate, encoding antigens matched to all four WHO-recommended flu strains. Reactogenicity, safety, and immunogenicity were assessed in 480 healthy younger adults aged 18 to 64 and 480 healthy older adults aged 65 to 85. In each age group, three different dose levels were tested in comparison to an age-appropriate, licensed comparator vaccine. For younger adults, immune responses were compared to a standard dose seasonal vaccine. For older adults, immune responses were compared to a high dose seasonal flu vaccine.