Lyme disease vaccine induces antibodies in Phase II clinical trial.
SHORT SUMMARY: The engineered protein vaccine VLA15 induces multiple antibodies in a Phase II trial and has the potential to provide protection against the different bacteria that cause Lyme disease in North America and Europe.
Lyme disease is caused by bacteria (Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii) that are delivered by a bite from an infected tick. Although antibiotics can treat Lyme disease, some people do not realize they have been infected. The longer a person waits to receive treatment, the worse the outcome is likely to be. Thus, an effective vaccine would be tremendously helpful for people in regions where the disease-carrying ticks are common. Indeed, the Centers for Disease Control (CDC) in the U.S. estimates ~300,000 people are infected annually.
Valneva is a company that has completed Phase II clinical trials with a vaccine that contains parts of the protein called OspA from multiple bacterial strains. This means the vaccine could provide protection against more than one type of Lyme disease-causing bacteria. Importantly, the vaccine should be effective against the species and serotypes common in Europe — B. burgdorferi (serotype 1), B. afzelii (serotype 2), B. garinii (serotypes 3, 5, and 6) and B. bavariensis (serotype 4) — and the one species in North America — B. burgdorferi. The vaccine is called VLA15.
In anticipation of the positive Phase II clinical trials with VLA15, Pfizer and Valneva formed a collaboration to bring the vaccine through Phase III trials and into the market. The first Phase II trial included healthy adults (18–65 years old). The participants were divided into 3 groups: ~90 in the placebo group, ~180 in the group that received 3 injections of a low dose (135 µg), and ~180 in the group that received 3 injections of a high dose (180 µg). The researchers measured IgG antibodies against 6 OspA serotypes one month after the last injection.
The response in the group receiving the higher dose was seroconversion rates of 81.5% to one of the serotypes to 95.8% to a second serotype. Seroconversion means that the subject did not have antibodies against these molecules before immunization and did have antibodies after immunization with VLA15. Encouragingly, prior exposure to Lyme-causing bacteria and the presence of antibodies against OspA did not affect the development of the specific IgG antibodies to the proteins in the vaccine or did not compromise safety. The subjects were followed for 1 year.
A second Phase II study is underway. This study tests the same doses but with longer times between the three injections. Valneva expects to report those data in a few months, as well as data on the functionality of the antibodies induced by the vaccine. Valneva has developed a serum bactericidal antibody assay to test the ability of the antibodies to kill the bacteria in serum samples.
With funding from Pfizer, the next phases of VLA15 testing should proceed quickly. If the antibodies induced during the Phase II trial prove toxic to the Lyme disease-causing bacteria and Phase III testing shows that the vaccine is effective and safe, the commercial capabilities of Pfizer should be able to bring the vaccine to market quickly.
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