Pfizer and Valneva SE announced that the European Medicines Agency (EMA) has validated their Marketing Authorization Application (MAA) for PF-07307405, an investigational six-valent outer surface protein A (OspA)-based vaccine candidate for the prevention of Lyme disease. With validation complete, the EMA will begin its formal assessment of the application.

The regulatory milestone follows results from the Phase 3 VALOR (Vaccine Against Lyme for Outdoor Recreationists) clinical trial, which evaluated the vaccine candidate in individuals aged five years and older. The trial demonstrated more than 70 percent efficacy in preventing Lyme disease, while the candidate was reported to be well tolerated, with no safety concerns identified.

The vaccine candidate is being developed through a collaboration between Pfizer and Valneva. Under an agreement established in April 2020, the companies are jointly developing PF-07307405, with Pfizer holding exclusive responsibility for its manufacturing and commercialisation, subject to regulatory approval.

If approved, PF-07307405 could become the first human Lyme disease vaccine available in Europe. There are currently no approved human vaccines for Lyme disease, and PF-07307405 is among the most advanced Lyme disease vaccine candidates in clinical development, having completed two pivotal Phase 3 trials.

PF-07307405 is a multivalent protein-subunit vaccine designed to target OspA, a protein found on Borrelia burgdorferi bacteria responsible for Lyme disease. Following vaccination, the body produces antibodies against six OspA serotypes. When an infected tick feeds on a vaccinated individual, the antibodies can enter the tick during feeding and bind to OspA, inhibiting the bacteria from leaving the tick and reducing the likelihood of transmission to the human host.

The vaccine candidate is designed to cover six of the most prevalent OspA serotypes expressed by Borrelia burgdorferi sensu lato species found in North America and Europe.

The VALOR study was a multicentre, randomised, placebo-controlled and observer-blinded Phase 3 trial conducted across regions of the US, Canada and Europe with high Lyme disease incidence. A total of 9,437 participants aged five years and older were randomised to receive either PF-07307405 or saline placebo.

Participants received four doses, with vaccinations administered at months 0, 2 and 5–9, followed by a fourth dose one year later before the subsequent Lyme disease season. The trial evaluated the candidate’s efficacy, safety, tolerability, immunogenicity and manufacturing lot consistency.

Lyme disease is a systemic infection caused by Borrelia burgdorferi sensu lato bacteria and transmitted primarily through the bite of infected Ixodes ticks. It is considered the most common vector-borne disease in the Northern Hemisphere.

In Europe, surveillance systems report more than 100,000 cases annually, while the US Centers for Disease Control and Prevention estimates that approximately 476,000 people are diagnosed and treated for Lyme disease each year in the US.

Early symptoms can include erythema migrans, fatigue, fever, headache, muscle and joint pain and mild neck stiffness. If untreated, the infection can spread and lead to complications affecting the skin, joints, heart and nervous system.

Pfizer said the potential vaccine could provide an additional layer of protection as Lyme disease continues to pose a growing public health challenge. Valneva highlighted the significance of the regulatory milestone given that more than 200 million people in Europe live in areas considered at risk of Lyme disease.

The EMA’s validation marks the beginning of the regulatory review process. The potential availability of PF-07307405 in Europe will depend on the outcome of the agency’s assessment and subsequent regulatory decision.