Chikungunya Vaccine for Adolescents Shows Positive Topline Results in Phase 3 Trial


PXVX0317 has received Fast Track and Breakthrough Therapy designation from the FDA.

Topline phase 3 results have been released for the virus-like particle (VLP)-based chikungunya virus vaccine candidate PXVX0317 (CHIKV VLP; Bavarian Nordic) for adolescents and adults aged 12 to 64 years, according to a press release from Bavarian Nordic.1

According to Bavarian Nordic, no effective treatments or vaccines for chikungunya virus are currently available. Caused by the chikungunya virus, chikungunya is a mosquito-borne viral disease that can present with symptoms such as rash, headache, fever, fatigue, and often severe and incapacitating join pain. Approximately 50% of people with chikungunya disease have debilitating, long-term symptoms which could intensify with age, according to the press release. In prior non-endemic regions in Asia, Africa, the Americas, and southern Europe, chikungunya virus has emerged over the last 20 years.

The randomized, multi-center, double blind, and placebo-controlled trial (NCT05072080) enrolled 3254 participants to receive either a single intramuscular injection of PXVX0317 or placebo. Up to 22 days post-vaccination, results demonstrated that PXVX0317 was “highly immunogenic” in health adolescents and adults as the induction of chikungunya neutralizing antibodies in 98% of vaccinees in the active group. The primary outcome of the trial was a marker of seroprotection. The neutralizing antibody titres were equal to or greater than the agreed upon threshold from authorities as a marker of seroprotection.

PXVX0317 resulted in neutralizing antibodies in 97% of individuals 2 weeks after vaccination, highlighting the “rapid onset of protective levels of immunity,” according to Bavarian Nordic. At 6 months post-vaccination, 86% of individuals had seroprotective levels of neutralizing antibodies, highlighting that responses were well tolerated and durable.

Adverse events, according to the company, were mainly mild or moderate in nature. In both adult and adolescent populations, PXVX0317 was well-tolerated.

Bavarian Nordic released topline results from another phase 3 adult (≥ 65 years) trial (NCT05349617), which revealed 87% of PXVX0317-treated individuals achieved neutralizing antibodies 22 days after a single vaccination.

According to the manufacturer, PXVX0317 has received Fast Track and Breakthrough Therapy designation from the FDA. Results from both phase 3 studies “will form the basis for submission of a Biologics License Application (BLA) to the FDA and a Marketing Authorization Application (MAA) to the European Medicines Agency (EMA) in 2024 to support potential launch of the vaccine in 2025.”

This article originally appeared on Contemporary Pediatrics.

1. Bavarian Nordic reports positive phase 3 topline results for chikungunya virus vaccine in adults and adolescents. Bavarian Nordic. Press release. August 6, 2023. Accessed August 14, 2023.
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