In May 2024, Valneva reported positive pivotal Phase III data in adolescents for the single-shot chikungunya virus (CHIKV) vaccine, VLA1553. It is expected that these data will support licensure of IXCHIQ in Brazil, which would be the first potential approval for use in endemic populations after the November 2023 approval by the US FDA. The most recent analysis of VLA155-321 evaluated the safety and immunogenicity six months after vaccination with a single dose of the vaccine, confirming “initial positive immunogenicity and safety data”. This supports filing for a potential label extension for adolescents between 12 and 17.
High, sustained immune response
The data confirm that a single-dose vaccination with VLA1553 induced a “high, sustained immune response” with a seroresponse rate of 99.1% percent at Day 180. This compares with 98.8% on Day 29. GMTs “consistently surpassed” the seroresponse threshold as the surrogate of protection in baseline seronegative participants who received a single dose of VLA1553.
Furthermore, the Day 180 data confirmed that a single dose was “generally safe and well tolerated” in adolescents receiving VLA1553, irrespective of previous infection with the virus. An Independent Data Safety Monitoring Board “consistently” assessed safety data throughout the trial, finding no safety issues.
The trial, conducted in collaboration with Instituto Butantan in Brazil with funding from CEPI and support EU Horizon 2020, is the first clinical trial conducted in an endemic area and with individuals previously infected with CHIKV.
Encouraging data
Dr Juan Carlos Jaramillo, Chief Medical Officer, is “highly encouraged” by the data, which “reinforce the strong immunity and safety observed in adults and the elderly”.
“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.”
In our conversation with Thomas Lingelbach, CEO of Valneva, at the Congress in Washington last month, we heard about his pride in the team’s progress on this chikungunya vaccine; do check out the interview here. We hope to hear more on this from the team during the Congress in Barcelona this October, so don’t forget to get tickets now. For more vaccine updates don’t forget to subscribe to our weekly newsletters here.
