Valneva has shared positive results from a late-stage study of its single-dose chikungunya vaccine in adolescents aged 12 to 17 years.
The vaccine, Ixchiq, is already approved in the US, Europe and Canada to prevent the mosquito-borne viral disease in individuals aged 18 years and older.
Valneva said the updated results from the phase 3 VLA1553-321 trial “strengthen” the pivotal data previously reported for Ixchiq in adolescents, which supported label extension applications for the vaccine in this age group.
The new one-year VLA1553-321 data showed that a single dose of Ixchiq induced a high, sustained immune response in an immunogenicity subset of adolescents who were chikungunya-negative at baseline, with a seroresponse rate of 98.3% one year after vaccination compared to 99.1% after six months and 98.8% after 28 days.
The updated results also confirmed that a single dose of the vaccine was generally well tolerated in this age group.
Chikungunya is spread by the bites of infected Aedes mosquitoes and often causes sudden, large outbreaks with high attack rates, affecting one-third to three-quarters of the population in areas where the virus is circulating.
Infection leads to symptomatic disease in up to 97% of people after three to seven days following the mosquito bite, with clinical symptoms including fever, joint and muscle pain, headache, nausea and rash.
Valneva’s chief medical officer, Juan Carlos, said: “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 where vaccine access is often limited.”
Carlos added that the company is expecting to report the first clinical data for Ixchiq in children “imminently”.
The results come less than two months after Valneva reported positive three-year antibody persistence data for Ixchiq in adults.
Among the 278 healthy adults still enrolled in the trial, 96% maintained neutralising antibody titres well above the seroresponse threshold three years after vaccination, and persistence of antibodies in adults aged 65 years and older was comparable to those aged 18 to 64 years.