By Tristan Manalac


Pictured: Sign in front of FDA building/iStock, JHVEPhoto
The FDA has delayed its PDUFA action date for Valneva’s investigational chikungunya vaccine VLA1553 to the end of November, the company announced Monday. The original decision was due by the end of August.
The regulator extended the review period “to allow sufficient time to align and agree on a phase 4 program,” as required under the agency’s accelerated approval pathway, according to Valneva’s announcement. The FDA did not request additional clinical data to support the application.
VLA1553, a live-attenuated investigational shot, could be “the first vaccine candidate to be approved under the accelerated approval pathway in an outbreak disease,” Valneva Chief Medical Officer Juan Carlos Jaramillo said in a statement. This makes its Phase IV plan all the more important as it will set a “future standard” for the industry.
Despite the PDUFA delay, Valneva still expects to launch the product in 2023 if it gets approval. The extension also does not affect regulatory submissions in other territories.
In June 2023, the French biotech released Phase III findings showing that VLA1553 elicits a strong immune response. The data, published in the medical journal The Lancet, demonstrated high rates of seroprotection reaching 98.6% in adults aged 18 to 64 years and 100% in those 65 years old and above.
VLA1553 is also designed to be given in a single dose and can elicit immunity in a matter of weeks, which is crucial to preventing chikungunya outbreaks.
Monday’s PDUFA delay, however, could give its chief competitor Bavarian Nordic some time to catch up. Last week, the Danish biotech also released Phase III data for its vaccine candidate CHIKV VLP showing that the investigational shot could induce anti-chikungunya antibodies in 98% of patients aged 12 to 64 years.
In addition, 97% of inoculated study participants developed these antibodies within two weeks of vaccination, which indicates that the candidate elicits “a rapid onset of protective levels of immunity,” the company said in its announcement.
These data followed an earlier release, in June 2023, showing that the vaccine candidate was likewise effective in older adults aged 65 and above.
Bavarian Nordic will use the results of both studies for regulatory applications next year, and anticipates potential product launch in 2025.
Valneva and Bavarian Nordic are the frontrunners in the race to bring a chikungunya vaccine to the market after Merck discontinued its chikungunya program in February 2023, as reported by Fierce Biotech, citing a company spokesperson who said that the cuts were part of a routine pipeline reorganization.