This week, Pfizer and Valneva announced that the participants of the phase 3 trial “have completed the primary vaccination series, 3 doses of Lyme disease vaccine candidate, VLA15. Participants will be monitored for the occurrence of disease until the end of the Lyme disease season in 2025.
This study is part of their Vaccine Against Lyme for Outdoor Recreationists (VALOR) trial. The trial is a multicenter, placebo-controlled, randomized, observer-blinded trial conducted at sites in areas where Lyme disease is highly endemic across the U.S., Canada, and Europe. The aim of the trial is to evaluate the efficacy, safety, tolerability, immunogenicity, and lot consistency of VLA15, a 6-valent OspA-based Lyme disease vaccine candidate.1 Trial participants aged 5 years and older were randomized 1:1 into two trial groups and receive four doses of either VLA15 or a saline placebo – one dose each at months 0, 2, 5-9 and a booster one year after the third dose, shortly before the peak of the next Lyme disease season.1
“The completion of the primary series of our VALOR trial is a critical step toward our goal of providing a safe and effective vaccine against Lyme disease,” said Annaliesa Anderson, PhD, senior vice president and head of Vaccine Research and Development, Pfizer. “VLA15, the Lyme disease vaccine candidate we are co-developing with Valneva, is the one which has advanced the furthest along the clinical development timeline, with two phase 3 trials in progress.”1
What the Data Has Shown
In late 2022, the companies reported data demonstrating the vaccine its antibody levels remained above baseline six months after completion of a three-dose (Month 0-2-6) or a two-dose (Month 0-6) vaccination schedule.2
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 in 84 healthy adults and 78 pediatric participants (5-17 years of age) for the Month 0-6 schedule.2
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 highest 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).2
The Vaccine’s Makeup
According to Pfizer and Valneva, this investigational multivalent protein subunit vaccine uses an established mechanism of action for a Lyme disease vaccine that targets the outer surface protein A (OspA) of Borrelia burgdorferi, the bacteria that cause Lyme disease. OspA is a surface protein expressed by the bacteria when present in a tick. Blocking OspA inhibits the bacterium’s ability to leave the tick and infect humans. The vaccine candidate covers the six most prevalent OspA serotypes expressed by the Borrelia burgdorferi sensu lato species in North America and Europe.1
Pfizer and Valneva entered into a collaboration agreement in April 2020 to co-develop VLA15, with updates to the terms within this agreement made back in June 2022.
