Pfizer Inc. and Valneva SE announced the initiation of a Phase 3 clinical study, Vaccine Against Lyme for Outdoor Recreationists (VALOR) (NCT05477524), to investigate the efficacy, safety and immunogenicity of their investigational Lyme disease vaccine candidate, VLA15. The randomized, placebo-controlled, Phase 3 VALOR study is planned to enroll approximately 6,000 participants 5 years of age and older. The study is being conducted at up to 50 sites located in areas where Lyme disease is highly endemic, including Finland, Germany, the Netherlands, Poland, Sweden and the United States.

Participants 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). Data from the Phase 2 studies continue to demonstrate strong immunogenicity in adults as well as in children, with acceptable safety and tolerability profiles in both study populations.1,2 Pending successful completion of the Phase 3 study, Pfizer could potentially submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) and Marketing Authorisation Application (MAA) to the European Medicines Agency (EMA) in 2025. As per the terms of the collaboration agreement between Pfizer and Valneva, Pfizer will make a $25 million milestone payment to Valneva upon initiation of the Phase 3 study.

VLA15 is the only Lyme disease vaccine candidate currently in clinical development. 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 covers the six most common OspA serotypes expressed by the Borrelia burgdorferisensulato species that are prevalent in North America and Europe. VLA15 has demonstrated a strong immune response and satisfactory safety profile in pre-clinical and clinical studies so far.

Valneva and Pfizer entered into a collaboration agreement in April 2020 to co-develop VLA15, with updates to the terms within this agreement made in June 2022.3,4 The terms of the collaboration agreement include a $25 million milestone payment made to Valneva upon Pfizer's initiation of the Phase 3 study. The program was granted Fast Track designation by the U.S. FDA in July 2017.