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Valneva Reports Further Positive Pivotal Phase 3 Data in Adolescents for its Single-Shot Chikungunya Vaccine


Results Intended to Support Filing for Potential Label Extension for Use in Adolescents

Saint-Herblain (France), May 13, 2024Valneva SE (Nasdaq: VALN; Euronext Paris: VLA), a specialty vaccine company, today reported further positive pivotal Phase 3 data in adolescents for its single-shot chikungunya virus (CHIKV) vaccine. Following the initial analysis up to Day 29 post-vaccination, the most recent analysis of study VLA1553-321 evaluated the safety and immunogenicity six months (Day 180) after vaccination with a single dose of the vaccine. The Day 180 results confirm the initial positive immunogenicity and safety data Valneva reported previously1,2, and are intended to support filing for potential label extension for use in adolescents aged 12 to 17 years. The data are also expected to support licensure of IXCHIQ® in Brazil, which would be the first potential approval for use in endemic populations.

The latest VLA1553-321 data confirmed that a single-dose vaccination with VLA1553 induced a high, sustained immune response with a seroresponse rate of 99.1% (232 out of 234 participants) at Day 180 compared to 98.8% (248 out of 251 participants) at Day 29 in an immunogenicity subset of individuals who were CHIKV negative at baseline.

Geometric mean antibody titers (GMTs) consistently surpassed the seroresponse threshold defined with the U.S. Food and Drug Administration (FDA)3 as the surrogate of protection in baseline seronegative participants who received a single dose of VLA1553.

Additionally, the Day 180 data confirmed that a single dose of the vaccine was generally safe and well tolerated in adolescents receiving VLA1553, irrespective of previous infection with the chikungunya virus. Throughout the trial, an Independent Data Safety Monitoring Board (IDSMB) consistently assessed safety data and found no safety issues. The majority of solicited adverse events observed following VLA1553 administration were mild or moderate and resolved within three days post vaccination.

Juan Carlos Jaramillo M.D., Chief Medical Officer of Valneva, said, “We are highly encouraged by these data, as they reinforce the strong immunity and safety observed in adults and the elderly, upon which FDA approval was granted. Given the substantial risk that chikungunya presents to individuals residing in or traveling to endemic regions, it’s imperative to ensure the vaccine is available to all age groups. This broader accessibility can help provide protection and mitigate the burden of this debilitating illness.”

Conducted in collaboration with Instituto Butantan in Brazil and funded by the Coalition for Epidemic Preparedness Innovations (CEPI) with support from the European Union’s Horizon 2020 program, the VLA1553-321 trial represents the first clinical trial conducted in an endemic area and with individuals previously infected with CHIKV.

Valneva’s vaccine IXCHIQ® is the world’s first and only licensed chikungunya vaccine available to address this significant unmet medical need. It was approved by the U.S. FDA in November 20234, and the Centers for Disease Control and Prevention (CDC) recently adopted the Advisory Committee on Immunization Practices’ (ACIP) recommendations on use of the vaccine in the U.S.5. Three marketing applications are currently under review by the European Medicines Agency, Health Canada and the Brazilian Health Regulatory Agency (ANVISA) with potential approvals in 2024. IXCHIQ®’s final pivotal Phase 3 data were published in The Lancet, the world’s leading peer-reviewed medical journal, in June 20236.

About Phase 3 Study VLA1553-321
VLA1553-321 is a prospective, double-blinded, multicenter, randomized, placebo-controlled pivotal Phase 3 trial conducted in 754 adolescents aged 12 to 17 years old in Brazil. The VLA1553-321 clinical trial was initiated in January 2022 and Valneva reported initial immunogenicity and safety data in November7 and August 20238, respectively. VLA1553 or placebo was administered as a single intramuscular immunization to participants who were randomized into two study groups at a 2:1 ratio. The primary objective is to evaluate the immunogenicity and safety of the adult dose of VLA1553 in adolescents 28 days following a single vaccination. Secondary objectives of the trial include assessment of safety and immunogenicity up to twelve months following a single vaccination with VLA1553. Additional information, including a detailed description of the study design, eligibility criteria and investigator sites, is available at (Identifier: NCT04650399).


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