Lyme Disease Vaccine Benefits from Booster Dose

France-based Valneva SE and Pfizer Inc. today announced further positive Phase 2 study results, including booster vaccination response, for Lyme disease vaccine candidate VLA15.

VLA15 is the only active Lyme disease vaccine candidate in clinical development.

The Phase 2 study, VLA15-202, evaluates the immunogenicity and safety of VLA15 in a Month 0-2-6 vaccination schedule with 246 healthy adults 18 to 65 years of age in the U.S.

Participants who received a complete primary vaccination series with 180 µg doses of VLA15 were invited to continue the study in a booster extension phase and were randomized to receive an additional 180 µg dose of VLA15 (N=39) or placebo (N=19) at Month 18.

VLA15’s acceptable safety profile was confirmed through a one-month post-booster.

Administration of a booster dose elicited a strong anamnestic response yielding a 2.9-fold (ST3) to 4.2-fold (ST1, ST4) increase (Geometric Mean Fold Rise) in anti-OspA IgG antibody titers compared with titers observed after primary immunization.

All participants seroconverted to anti-OspA IgG after the booster dose, meaning Seroconversion Rates (SCRs) were 100% for all OspA serotypes. SCR was defined as the rate of subjects that changed from seronegative at baseline to seropositive.

Additionally, seropositive subjects at baseline needed to show at least a 4-fold increase in anti-OspA IgG compared to baseline titer.

The functionality of elicited antibodies was demonstrated by Serum Bactericidal activity Assays, leading to SCRs ranging from 86.8% (ST2) to 100.0% (ST3) after the booster. The study is continuing to monitor the persistence of antibody responses.

“The prevalence and geographic reach of Lyme disease are growing, underscoring the major medical need for vaccination against the disease,” commented Kathrin Jansen, Ph.D., SVP, and Head of Pfizer Vaccine Research and Development, in a press statement.

Valneva and Pfizer announced a collaboration for VLA15’s development and commercialization at the end of April 2020. The two companies are working closely together on the subsequent development steps and are planning for a Phase 3 trial in 2022.

Valneva is a specialty vaccine company located in Saint-Herblain (France), focused on the development and commercialization of prophylactic vaccines for infectious diseases with significant unmet medical need.