Pfizer and Valneva Lyme vaccine candidate shows more than 70% efficacy in Phase 3 VALOR trial

Pfizer and Valneva announced that their investigational Lyme disease vaccine candidate demonstrated more than 70% efficacy in preventing confirmed cases of Lyme disease in the phase 3 VALOR trial. Based on the phase 3 findings, Pfizer indicated it plans to proceed with submissions to regulatory authorities, with a Biologics License Application in the U.S. and a Marketing Authorisation Application in Europe still anticipated.

The vaccine candidate, PF-07307405 (LB6V), also dubbed VLA15, is a multivalent protein subunit vaccine targeting outer surface protein A (OspA) of Borrelia burgdorferi and is currently the most advanced Lyme disease vaccine in clinical development. In the phase 3 VALOR trial (NCT05477524), the vaccine demonstrated 73.2% efficacy from 28 days after the fourth dose (season 2) in reducing confirmed Lyme disease cases versus placebo (95% CI, 15.8–93.5) and 74.8% efficacy from 1 day after the fourth dose (season 2) (95% CI, 21.7–93.9).

Although fewer cases than expected were accrued during the study period and the predefined primary endpoint criterion was not met in the first analysis, the lower bound of the confidence interval exceeded 20 in the second analysis, which investigators described as clinically meaningful. The vaccine was reported to be well tolerated, with no safety concerns identified at the time of analysis.

The VALOR study was a multicenter, randomized, placebo-controlled, observer-blinded trial conducted in regions with high Lyme disease incidence across the United States, Canada, and Europe. Participants aged 5 years and older were randomized 1:1 to receive either the vaccine or saline placebo in a 4-dose series administered at months 0, 2, and 5–9, followed by a booster dose approximately one year later before the subsequent Lyme season.

PF-07307405 targets six OspA serotypes of Borrelia burgdorferi sensu lato, covering the most prevalent strains in North America and Europe. In April 2020, Pfizer began working with Valneva to help develop the Lyme disease vaccine candidate, which was in phase 2 trials at the time.

Valneva said ongoing research collaboration and licensing agreement revenue for the Lyme disease programme helped lift total revenue to €174.7 million in 2025, up from €169.6 million in 2024. Looking ahead, significant financial incentives tied to VLA15 include $143 million in near-term milestone payments upon approval, royalties between 14% and 22%, and up to $100 million in additional milestones.