Pfizer and Valneva have shared promising immune response and safety results from a mid-stage study of their Lyme disease vaccine candidate.
The phase 2 VLA15-221 trial randomised healthy participants to receive VLA15 or placebo during a primary vaccination phase, followed by a first booster dose at month 18 and a second at month 30.
There are currently no approved human vaccines for Lyme disease, a bacterial infection caught from the bite of an infected tick.
It is considered the most common vector-borne illness in the Northern Hemisphere and, if left untreated, can cause serious complications affecting the skin, joints, heart and nervous system.
New results from the study demonstrated a significant anamnestic antibody response across all six serotypes covered by the vaccine in paediatric, adolescent, adult and older adult participants, measured one month after administration of the second booster dose.
The safety and tolerability profile of the second booster was comparable to that observed after the first booster, the companies said, noting that no safety concerns have been observed in any treatment or age group to date.
Annaliesa Anderson, senior vice president and head vaccine research and development at Pfizer, said: “Personal preventive behaviours are currently the only recommended strategies to help protect yourself from Lyme disease.
“This data from the VLA15-221 study is an important step towards a potential vaccine that could help prevent the disease and ease the burden of acute, severe and sometimes persistent consequences.”
VLA15-221 is currently being evaluated in a phase 3 study of individuals aged five years and older in highly endemic regions in the US and Europe, and in another phase 3 trial that is aiming to provide further evidence on the safety profile of VLA15 in paediatric participants.
Pfizer is aiming to submit regulatory applications for the vaccine to the US Food and Drug Administration and European Medicines Agency in 2026, subject to positive phase 3 data.
Also commenting on the latest results for the candidate, Valneva’s chief medical officer, Juan Carlos Jaramillo, said: “As Lyme disease continues to spread, it represents a significant unmet medical need, affecting numerous individuals throughout the Northern Hemisphere.
“Each new set of positive data brings us one step closer to potentially bringing this vaccine to both adults and children living in areas where Lyme disease is endemic.”