Valneva SE (Nasdaq: VALN; Euronext Paris: VLA) and Pfizer Inc. (NYSE: PFE) today announced positive results from the VLA15-221 Phase 2 study of their Lyme disease vaccine candidate, VLA15, following the administration of a second booster dose one year after the first. The data revealed a robust immune response across all six serotypes targeted by the vaccine, consistent with previous findings, and demonstrated a favorable safety profile across all age groups.
VLA15 is the most advanced Lyme disease vaccine candidate currently in development, with no other human vaccines approved for this disease. The Centers for Disease Control and Prevention (CDC) estimates that Lyme disease affects approximately 476,000 people annually in the U.S., with 129,000 cases reported each year in Europe.
The latest Phase 2 results highlighted a significant anamnestic antibody response in both pediatric (ages 5-11) and adult (ages 18-65) populations, with over 90% of participants achieving seroconversion rates (SCRs) across all six OspA serotypes. Geometric Mean Titers (GMTs) remained high one month after both the first and second booster doses, indicating a sustained immune response.
Participants in this study were previously administered VLA15 or placebo in a primary vaccination series, followed by a first booster at month 18 and a second booster at month 30. The safety profile of VLA15 post-second booster was consistent with previous observations, with no safety concerns identified by the independent Data Monitoring Committee (DMC).
Juan Carlos Jaramillo M.D., Chief Medical Officer of Valneva, commented, “These encouraging data underscore the potential of booster doses across all age groups, particularly as Lyme disease continues to pose a growing threat in the Northern Hemisphere. We are steadily progressing towards the goal of providing a vaccine for both adults and children in Lyme-endemic areas.”
Annaliesa Anderson, Ph.D., Senior Vice President and Head of Vaccine Research and Development at Pfizer, added, “With no approved vaccines currently available, these Phase 2 results represent a critical step forward in potentially offering a preventive solution for Lyme disease, which can have severe and persistent effects. We are committed to advancing our vaccine candidate in the ongoing Phase 3 trials alongside Valneva.”
Pfizer and Valneva are currently conducting two Phase 3 studies, including the VALOR (NCT05477524) study, which investigates the efficacy, safety, and immunogenicity of VLA15 in participants five years and older in the U.S. and Europe. A second Phase 3 study (VLA15-1012) is focused on further evaluating the safety profile in the pediatric population. Subject to positive Phase 3 outcomes, Pfizer plans to submit regulatory applications to the U.S. FDA and the European Medicines Agency (EMA) in 2026.
