Valneva announced positive initial results for its second Phase 2 study of Lyme disease vaccine candidate VLA15. The study met safety and immunogenicity endpoints.
The second Phase 2 study, VLA15-202, was a randomized, observer-blind, placebo controlled trial conducted in the US. A total of 246 healthy adults received 135 µg or 180 µg of VLA15 (approximately 100 subjects each) or placebo (approximately 50 subjects). VLA15 was tested as alum adjuvanted formulation and was administered intramuscularly in three injections, given at Month 0, 2 and 6 (compared to Month 0, 1 and 2 in study VLA15-201). Subjects were followed for 18 months, with the main immunogenicity readout at one month after completion of the primary vaccination series (primary endpoint). Study centers 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 allowed to participate.
VLA15 was generally safe across all doses and age groups tested. The tolerability profile including fever rates was comparable to other similar recombinant vaccines or lipid containing formulations. No related Serious Adverse Events were observed in any treatment group. Reactogenicity decreased following the first vaccination.
Compared to study VLA15-201, the results of which were reported in July of 2020, immunogenicity was further enhanced using a Month 0-2-6 schedule. SCRs (Seroconversion Rates), after completion of the primary vaccination series, showed similar responses and ranged from 93.8% [ST1] to 98.8% [ST2, ST4]. Antibody responses were comparable in the two dose groups tested. Results did not indicate that prior exposure to Borrelia spirochetes (sero-positivity) has an impact on immunogenicity or safety, also as observed in VLA15-201.
A Serum Bactericidal Assay (SBA), assessing the functional immune response against Lyme disease after vaccination with VLA15, was conducted for the first time and demonstrated functionality of antibodies against all OspA serotypes. Assays, such as SBAs, are commonly used to enable a potential prediction of vaccine efficacy via the measurement of vaccine-induced functional immune responses.
Based on this data, Valneva and collaborative partner Pfizer plan to advance the program with the Month 0-2-6 schedule. The companies will finalize dosage analysis and prepare for the next development steps in the coming months.
VLA15 covers the six Lyme disease serotypes that are prevalent in North America and Europe. This 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.
The U.S. FDA has granted Fast Track designation for the program.
Valneva and Pfizer announced a collaboration for VLA15’s development and commercialization at the end of April 2020.
About Lyme Disease
Lyme disease is a systemic infection caused by Borrelia bacteria transmitted to humans by infected Ixodes ticks. 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 are diagnosed with Lyme disease each year with at least a further 200,000 cases in Europe. Early symptoms of Lyme disease include a gradually expanding erythematous rash called Erythema migrans and faigue, fever, headache, mild stiff neck, joint pain and muscle pain. Left untreated, the disease can disseminate and cause more serious complications affecting the joints (arthritis), the heart (carditis) or the nervous system.