Valneva Plunges As Lyme Vaccine Misses Key Goal In Phase 3 Trial; Shows More Than 70% Efficacy

(RTTNews) - Valneva SE (VALN) saw its stock drop sharply, even as the company and partner Pfizer announced that their Lyme disease vaccine candidate demonstrated more than 70% efficacy in a large Phase 3 study.

Lyme disease, spread through tick bites, affects hundreds of thousands of people each year in the U.S. and Europe. With no approved human vaccine currently available, the medical community has long viewed a preventive shot as a major unmet need.

Strong Efficacy, But Missed a Primary Endpoint

The Phase 3 VALOR trial evaluated the investigational 6-valent OspA-based vaccine PF-07307405 (LB6V) in individuals aged five and older. According to the topline results, the vaccine reduced confirmed Lyme disease cases by:

-73.2% from 28 days after the fourth dose

-74.8% from one day after the fourth dose

Both analyses showed clinically meaningful protection. However, because fewer Lyme cases occurred than expected during the study period, the first pre-specified analysis did not meet the statistical threshold required for the primary endpoint. Even so, Pfizer noted that the second analysis-where the lower bound of the confidence interval exceeded 20%- supports confidence in the vaccine's potential.

Safety Profile and Expert Reaction

The vaccine was well tolerated, with no safety concerns identified at the time of analysis. Pfizer's Chief Vaccines Officer, Annaliesa Anderson, called the results "highly encouraging," emphasizing the need for a preventive option for a disease that can cause long-term complications if untreated. Valneva CEO Thomas Lingelbach said the findings bring the companies "a step closer" to delivering a much-needed vaccine.

How the Vaccine Works

The candidate targets outer surface protein A (OspA) on the Lyme-causing Borrelia bacteria. When a vaccinated person is bitten by a tick, antibodies generated by the vaccine are taken up by the tick and block the bacteria from leaving the tick's gut- preventing transmission to humans. The vaccine covers the six most common OspA serotypes found in North America and Europe.

Next Steps

Pfizer plans to move forward with regulatory submissions, citing the strong efficacy and safety profile. If approved, PF-07307405 would become the first human Lyme disease vaccine available in decades. Financial Position

Valneva ended 2025 with €109.7 million, in cash and cash equivalents, according to its recently reported full-year financial results. The company said cash management will remain a priority, with operating cash burn expected to decline further in 2026 while still supporting strategic R&D investments.

VALN has traded between $5.43 and $12.25 over the past year. The stock closed Friday's trading (March 20, 2026) at $10.32, down 1.67%. In pre-market trading the stock is at $6.70, down 35.08%.

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