Pfizer Inc. and Valneva SE reported antibody persistence data six months after the completion of a three-dose (Month 0-2-6) or a two-dose (Month 0-6) vaccination schedule with their Lyme disease vaccine candidate, VLA15 in both children and adults. This is the first time antibody persistence data are reported in pediatric populations for this vaccine candidate. Following positive immunogenicity and safety data for Phase 2 study VLA15-221 in April 20221, Valneva and Pfizerevaluated the persistence of antibodies six months after the Month 0-2-6 and the Month 0-6 vaccination schedule with VLA15 in healthy adults and pediatric participants (5 to 65 years of age).

Data were collected in 96 healthy adults and 81 pediatric participants (5-17 years of age) for the Month 0-2-6 vaccination schedule and in84 healthy adults and 78 pediatric participants (5-17 years of age) for the Month 0-6 schedule. As observed in previous clinical studies with VLA15, antibody levels declined over time in all study groups but remained above baseline, confirming their persistence six months after completion of both vaccination schedules. Overall, antibody levels remained higher with the three-dose vaccination schedule compared to the two-dose schedule.

Geometric mean fold rise (GMFRs) compared to baseline were 1.9-fold for Serotype 1 (ST1) to 3.2-fold Serotype 2 (ST2) across all age groups in the Month 0-2-6 vaccination schedule. The higher GMFRs were reported in the 5 to 11 years old age group, with GMFR levels at 2.8-fold (ST1) to 6.6-fold (ST2). Earlier this year, Pfizer and Valneva initiated a Phase 3 clinical study, Vaccine Against Lyme for Outdoor Recreationists (VALOR) (NCT05477524), to investigate the efficacy, safety and immunogenicity of VLA152.

Approximately 6,000 participants 5 years of age and older will receive three doses of VLA15 180 µg or saline placebo as a primary vaccination series followed by one booster dose of VLA15 or saline placebo (1:1 ratio). Enrollment is ongoing in Europe and the United States and expected to be completed in the second quarter of 2023.