Valneva and Pfizer Report Further Positive Phase 2 Booster Results for Lyme Disease Vaccine Candidate

• VLA15-221 Phase 2 study: robust immune response demonstrated one month after a second booster dose (month 31) in pediatric and adult populations
• Significant anamnestic antibody response observed across all six serotypes, consistent with previous results
• Favorable safety profile of VLA15 observed in all age groups and for all vaccinations

Saint-Herblain (France) and New York, NY, September 3, 2024 – Valneva SE (Nasdaq: VALN; Euronext Paris: VLA) and Pfizer Inc. (NYSE: PFE) today announced positive immunogenicity and safety data from their VLA15-221 Phase 2 study following a second booster vaccination of their Lyme disease vaccine candidate, VLA15, given one year after receipt of the first booster dose. The immune response and safety profile of VLA15 one month after receipt of the second booster dose were comparable to those reported after receipt of the first booster dose, demonstrating compatibility with the expected benefit of a booster vaccination prior to each Lyme season. There are currently no approved human vaccines for Lyme disease and VLA15 is the Lyme disease vaccine candidate that is furthest along in its clinical development timeline, with two Phase 3 studies ongoing. According to estimates from the Centers for Disease Control and Prevention (CDC), approximately 476,000 people in the U.S. are diagnosed and treated for Lyme disease each year. In Europe, 129,000 cases are reported each year.^1,2

These latest results from the VLA15-221 Phase 2 study again demonstrated significant anamnestic antibody responses across all six serotypes covered by the vaccine candidate in pediatric (5 to 11 years) and adolescent (12 to 17 years) participants, as well as in adults (18 to 65 years), measured one month after administration of this second booster dose (month 31). A high percentage of participants seroconverted following the second booster dose, resulting in seroconversion rates^* (SCRs) above 90% for all outer surface protein A (OspA) serotypes in all age groups, consistent with SCRs after the first booster. Geometric mean titers one month after the first and second boosters (i.e., month 19 vs. month 31) were similarly high.