Valneva's Phase III trial of chikungunya vaccine meets all endpoints

French vaccines developer Valneva (Euronext Paris: VLA) announced the successful completion of the Phase III pivotal trial of its single-shot chikungunya vaccine candidate, VLA1553, sending the firm’s shares up as much as 7.4% to 13.86 euros on Tuesday.

The positive final analysis included six-month follow-up data and confirmed the top-line results reported in August 2021. Valneva now expects to commence the pre-submission process with the US Food and Drug Administration in the second quarter of 2022.

The VLA1553-301 trial, which enrolled 4,115 adults aged 18 years and above across 44 sites in the USA, met all primary and secondary endpoints. The final analysis confirmed the very high level of seroprotection, with 98.9% of participants achieving protective levels of chikungunya virus (CHIKV) neutralizing antibodies one month after receiving a single vaccination (263 of 266 subjects from the per-protocol subgroup tested for immunogenicity, 95% CI: 96.7-99.8). The excellent immunogenicity profile was maintained over time, with 96.3% of participants showing protective CHIKV neutralizing antibody titers six months after receiving a single vaccination (233 of 242 subjects from the per-protocol subgroup tested for immunogenicity, 95%CI: 93.1-98.3). The reported levels of seroprotection far exceeded the 70% threshold (for non-acceptance) based on a surrogate of protection agreed with the FDA under the accelerated approval pathway.