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Positive Results Reported for Phase 2 Study of Lyme Disease Vaccine Candidate

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Valneva SE (“Valneva”), a specialty vaccine company focused on prevention of diseases with major unmet needs, today announced positive initial results for its first Phase 2 study (VLA15-201) of Lyme disease vaccine candidate VLA15.

VLA15 was immunogenic across all dose groups tested. Compared to Phase 1, the higher doses used in this trial elicited higher antibody responses across all serotypes. Seroconversion rates (SCR) in the highest dose ranged from 81.5% (ST1) to 95.8% (ST2). In the age group comparable to the age group investigated in Phase 1 (18-49 years), SCRs ranged from 85.6% to 97%. The immunological response in older adults, one of the main target groups for a Lyme vaccine, is particularly encouraging.

Results did not indicate that prior exposure to Lyme (sero-positivity) has an impact on immunogenicity or safety.

As part of further Phase 2 data to be released in a few months, an analysis of the functionality of the antibodies generated with VLA15 will be conducted. In close collaboration with regulatory authorities, Valneva has developed a Serum Bactericidal Antibody assay (“SBA”) for that purpose.

VLA15 was generally safe across all dose and age groups tested. No related Serious Adverse Events (SAEs) were observed with VLA15 in this study in any treatment group. Reactogenicity decreased with subsequent vaccinations.

Overall, the tolerability profile including rates of fever appeared to be comparable to other lipidated recombinant vaccines or lipid-containing formulations.

Wolfgang Bender, MD, PhD, Chief Medical Officer of Valneva commented We are pleased to report a successful first Phase 2 trial of our vaccine candidate against Lyme disease, a severe infection which affects an increasing number of people each year. Further data from the ongoing Phase 2 trials in the coming months will support further dose and schedule decisions. We are closely working with Pfizer to advance the development of VLA15 expeditiously.”

This first Phase 2 study, conducted in the EU and US, included 572 healthy adults aged 18 to 65 years. In the main study phase, 452 subjects received one of two dose levels (either 135µg or 180µg) of VLA15 (approximately 180 subjects each) in three injections (Days 1, 29 and 57) or placebo (approximately 90 subjects). Immunogenicity was measured by determining IgG antibodies against each of the six most prevalent Outer Surface Protein A serotypes of Lyme borreliosis in the US and Europe covered by the vaccine. The endpoint readout was immunogenicity at Day 85 (one month after finalization of primary immunization).

Valneva expects to report top-line results for the second Phase 2 study, VLA15-202, in a few months. In the VLA15-202 study, identical doses to the VLA15-201 study were tested using a longer vaccination schedule (Days 1, 57 and 180).

About VLA15

VLA15 is the only active Lyme disease vaccine in clinical development today, and covers six serotypes that are prevalent in North America and Europe. This investigational multivalent protein subunit vaccine targets the outer surface protein A (OspA) of Borrelia, an established mechanism of action for a Lyme disease vaccine. OspA is one of the most dominant surface proteins expressed by the bacteria when present in a tick. VLA15 has demonstrated strong immunogenicity and safety data in pre-clinical and Phase 1 studies. The program was granted Fast Track designation by the U.S. Food and Drug Administration (FDA) in July 2017[1].

Valneva and Pfizer announced a collaboration for VLA15’s development and commercialization at the end of April 2020[2]. The two companies are working closely together on the next development steps.

About Phase 2 Clinical Study VLA15-201

VLA15-201, the first of two parallel Phase 2 studies, is a randomized, observer-blind, placebo controlled study conducted in the US and Europe.

In a run-in Phase of the study, 120 subjects received one of three dosage levels of VLA15, or placebo. Following a positive review of safety data by an independent Data Safety Monitoring Board, 452 subjects received, in the main study phase, one of two selected dose levels of VLA15 (approximately 180 subjects each), or placebo (approximately 90 subjects).

VLA15 was tested as an alum-adjuvanted formulation and administered intramuscularly in three injections, given at Days 1, 29 and 57. Subjects, healthy adults 18 to 65 years of age, were followed for one year, with the main immunogenicity readout at Day 85 (Primary endpoint). Study centers for this study were located in areas where Lyme disease is endemic; subjects with a cleared past infection with Borrelia burgdorferi, the bacteria that cause Lyme disease, were also enrolled.

About Lyme Disease

Lyme disease is a systemic infection caused by Borrelia bacteria transmitted to humans by infected Ixodes ticks[3]. It is considered the most common vector borne illness in the Northern Hemisphere. According to the U.S. Centers for Disease Control and Prevention (CDC), approximately 300,000 Americans[4] are diagnosed with Lyme disease each year with at least a further 200,000 cases in Europe[5]. 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. The medical need for vaccination against Lyme disease is steadily increasing as the disease footprint widens[6].


1. Valneva Receives FDA Fast Track Designation for its Lyme Disease Vaccine Candidate VLA15

2.  Valneva and Pfizer Announce Collaboration to Co-Develop and Commercialize Lyme Disease Vaccine, VLA15

3. Stanek et al. 2012, The Lancet 379:461–473

4. As estimated by the CDC, https://www.cdc.gov/lyme/stats/humancases.html.

5. Estimated from available national data. Number  largely underestimated based on WHO Europe Lyme Report as case reporting is
highly inconsistent in Europe and many LB infections go undiagnosed; ECDC tick-borne-diseases-meeting-report

6. New Scientist, Lyme disease is set to explode and we still don’t have a vaccine; March 29, 2017

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