Valneva, a specialty vaccine company, today reported further positive Phase 3 data in adolescents for its single-shot chikungunya virus (CHIKV) vaccine, IXCHIQ, which showed a sustained 98.3% sero-response rate one-year after single vaccination. These results support and strengthen the pivotal data previously reported for adolescents (12 to 17 years old) which supported filing for potential label extension to this age group in the U.S., Europe, and Canada. Data from this trial are also expected to support licensure of IXCHIQ in Brazil, which would be the first potential approval for use in endemic populations.
The one-year VLA1553-321 data showed that a single-dose vaccination induced a high, sustained immune response in an immunogenicity subset of participants who were CHIKV negative at baseline, with a seroresponse rate of 98.3% (232 out of 236 participants) one year after vaccination (Day 360) compared to 99.1% (232 out of 234 participants) after six month (Day 180) and 98.8% (248 out of 251 participants) 28 days after vaccination. The results complement the long-term persistence data previously reported for adults, confirming a strong and long-lasting antibody response to the vaccine.
Geometric mean antibody titers (GMTs) consistently surpassed the seroresponse threshold defined with the U.S. Food and Drug Administration (FDA) as the surrogate of protection in baseline seronegative participants who received a single dose of the vaccine.
Additionally, the one-year data confirmed that a single dose of the vaccine was generally well tolerated in adolescents. Throughout the trial, an Independent Data Safety Monitoring Board (IDSMB) consistently assessed safety data and found no safety issues.
Juan Carlos Jaramillo M.D., Chief Medical Officer of Valneva, said, “These additional adolescent data confirm IXCHIQ’s ability to induce a robust, long-lasting antibody response in both younger people and adults with a single vaccination. 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 and has the potential to offer long-term protection, particularly in low- and middle-income countries (LMICs) where vaccine access is often limited. We are now looking forward to the first data in children which we expect to report imminently.”
Conducted in collaboration with Instituto Butantan in Brazil and funded by the Coalition for Epidemic Preparedness Innovations (CEPI) with support from the European Union (EU)’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. This trial supported the submission of label extension applications to the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA) and Health Canada to potentially extend the use of IXCHIQ to adolescents aged 12 to 17 years. Data from this trial may support regulatory approval of the vaccine in Brazil and other countries in Latin America.
Valneva expanded its partnership with CEPI, with support from the EU’s Horizon Europe programme, in the third quarter of 2024 through a $41.3 million grant to advance broader access to the vaccine in LMICs, including outbreak-affected countries, post-marketing studies and potential label extensions in children, adolescents and pregnant women. Within the framework of this agreement, Valneva recently announced the signing of an exclusive license agreement with the Serum Institute of India (SII), the world’s largest manufacturer of vaccines by number of doses, enabling the supply of the vaccine in Asia, with a commitment to priority supply of the chikungunya vaccine at an affordable price to public health markets in LMICs.
IXCHIQ is the world’s first and only licensed chikungunya vaccine available to address this significant unmet medical need. The vaccine is currently approved in the U.S., Europe, and Canada for the prevention of disease caused by the chikungunya virus in individuals 18 years of age and older. In addition to Brazil, Valneva also expects to receive marketing approval in the United Kingdom in the first quarter of the year.
