Pfizer and Valneva may have about two more years to wait before they make the first approval filing to the FDA for a Lyme disease vaccine, but that hasn’t stopped the companies collecting more positive data in the meantime.
The multivalent protein subunit vaccine, dubbed VLA15, is currently in a pair of phase 3 trials the companies hope will provide the backbone for a filing to the FDA and European regulators sometime in 2026. There are currently no approved vaccines for Lyme disease, a bacterial infection that is spread via the bite of an infected tick.
Today, the companies announced data from a phase 2 trial where participants had received a second booster shot a year after their first booster. The immune response and the safety profile of VLA15 when assessed a month after this second booster “were similar to those reported after receiving the first booster dose,” said the companies, which claimed the results demonstrated “compatibility with the anticipated benefit of a booster vaccination prior to each Lyme season.”
This morning’s readout showed a “significant anamnestic antibody response” across all six serotypes of the disease that are covered by the vaccine across children, adolescent and adult participants in the trial.
Specifically, the seroconversion rate (SCR)—the process by which the body produces antibodies in response to an infection or immunization—reached over 90% for all outer surface protein A serotypes in all age groups. This is in line with the SCRs recorded after the first booster was administered.
Geometric mean titers—a measurement of antibody level—at one month after both the first and second boosters were also “comparably high,” according to the Sept. 3 release. There was no change in safety profile between the two boosters across any of the age groups.
“We are encouraged by these data, which support the potential benefit of booster doses across all examined age groups,” Valneva Chief Medical Officer Juan Carlos Jaramillo, M.D., said in the release. “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.”
Pfizer and Valneva used this morning’s release to reiterate their intention to file VLA15 with the FDA and the European Medicines Agency in the 2026 off the back of data from two phase 3 trials. One of these studies completed its primary vaccinations in July, while the second phase 3 study is still ongoing.
The companies had previously set their sights on a 2025 filing date, before CRO issues at some of the phase 3 trial sites forced them to instigate a delay. Still, the placement of the pair of phase 3 studies means Pfizer and Valneva have the most advanced Lyme disease vaccine in development.