The Phase 2 trial, VLA15-221, compared the immunogenicity of a two dose or three dose vaccine regimen: leading to the choice of the three dose vaccine regimen for the Phase 3 trial.
The candidate, which is the only Lyme disease vaccine in clinical development, is being evaluated in people aged five years and above.
Phase 2 data
The multivalent protein subunit vaccine targets the outer surface protein A (OspA) of Borrelia burgdorferi, the bacteria that cause Lyme disease.
The vaccine covers six OspA serotypes expressed by the species that are prevalent in North America and Europe.
A changing climate has increased the threat of Lyme disease, with the ticks that carry the disease being found in a growing number of areas. With no vaccine available, VLA15 gained Fast Track designation from the US Food and Drug Administration (FDA) in July 2017, with Valneva and Pfizer entering into a collaboration agreement in April 2020 to co-develop the vaccine
The Phase 2 trial, VLA15-221, compared the immunogenicity of VLA15 after administration of two (at months 0 and 6) or three (at months 0, 2 and 6) primary series doses in groups aged 5-11, 12-17 and 18-65 years.
In the sub-analysis of adult participants (18-65 years old) who received VLA15 in either the two-dose schedule (N=90) or the three-dose schedule (N=97), performed one month after the last vaccination dose, VLA15 was found to be immunogenic with both vaccination schedules tested (pediatric data is expected to follow in the first half of 2022).
These data are consistent with the strong immunogenicity profile observed for this age group in previous Phase 2 studies. However, the induction of anti-OspA IgG (anti-outer surface protein A immunoglobulin G) antibody titers was higher in participants who received the three-dose primary series compared to those who received the two-dose primary series, supporting the use of a three-dose primary series schedule in the planned Phase 3 clinical trial.
The analysis was also consistent with the acceptable safety and tolerability profile observed in previous studies of VLA15. No vaccine-related serious adverse events (SAEs) were observed.
While the true incidence of Lyme disease is unknown, it is estimated to annually affect approximately 476,000 people in the United States and 130,000 people in Europe. Early symptoms of Lyme disease (such as a gradually expanding erythematous rash called Erythema migrans or more unspecific symptoms like fatigue, fever, headache, mild stiff neck, arthralgia or myalgia) are often overlooked or misinterpreted. Left untreated, the disease can disseminate and cause more serious complications affecting the joints (arthritis), the heart (carditis) or the nervous system.