Pfizer and Valneva said patients demonstrated “strong immune responses” after receiving a second booster dose of their experimental Lyme disease vaccine, supporting the case for annual dosing.
Patients in a Phase 2 trial were given a second booster dose of the protein-based vaccine VLA15 one year after receiving their first booster. At a one-month follow-up, they showed similar immune and safety responses to those observed after the first booster.
Valneva CEO Thomas Lingelbach has previously hypothesized that an annual booster will be required to protect patients, and the companies said Tuesday that the latest Phase 2 data show “compatibility” with that theory.
Juan Carlos Jaramillo“We are encouraged by these data, which support the potential benefit of booster doses across all examined age groups,” Valneva medical chief Juan Carlos Jaramillo said in a news release.
The results showed “significant anamnestic antibody response” across all six serotypes covered by the vaccine across three age groups, ranging from 5 to 65 years old. Pfizer and Valneva reported seroconversion rates — which measure the development of antibodies in response to a vaccine — above 90% for all outer-surface protein A serotypes in all age groups, in line with responses seen after the first booster dose.
Eugene Shapiro, a Yale University professor of pediatrics and epidemiology, told Endpoints News on Tuesday that the data aren’t surprising.
“However, the key issue is the actual clinical efficacy of the vaccine, which will be determined in the pivotal Phase 3 clinical trial, which is currently ongoing,” Shapiro said.
Pfizer put down $130 million upfront in 2020 to partner with Valneva on VLA15. The candidate targets a surface protein on the bacteria that cause Lyme disease, in the hopes of preventing the bacteria from leaving ticks and infecting humans. It’s currently in two Phase 3 trials, one of which is expected to read out by the end of 2025, Valneva said last month. The second Phase 3 is designed to collect further safety data in the pediatric population.
Pfizer hopes to file for approval in 2026, “subject to positive Phase 3 data,” the company said.