Single-Dose Chikungunya Vaccine Readies for Approval

France-based Valneva SE today announced the successful completion of a Phase 3 pivotal trial of its single-shot chikungunya vaccine candidate, VLA1553. The VLA1553-301 trial, which enrolled 4,115 adults aged 18 years and above across 44 sites in the U.S., met all primary and secondary endpoints.

The positive final analysis was confirmed on March 8, 2022, included six-month follow-up data and confirmed the topline results reported in August 2021.

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.

And 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.

VLA1553 was also confirmed to be highly immunogenic in elderly study participants.

The reported seroprotection levels far exceed the 70% threshold (for non-acceptance) based on a surrogate of protection agreed with the U.S. FDA under the accelerated approval pathway.

As a result, Valneva now expects to commence the pre-submission process with the FDA in the second quarter of 2022.

Juan Carlos Jaramillo, M.D, Chief Medical Officer of Valneva, commented in a press release, "These final pivotal Phase 3 results confirm the compelling profile of our single-shot vaccine candidate across all age groups."

"Delivering these Phase 3 results for a chikungunya vaccine candidate means that we are a step closer to addressing a major, growing, and unmet public health threat."

The Chikungunya virus 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.

There are no preventive vaccines or effective treatments available, and, as such, chikungunya is considered a major public health threat. 

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