Bavarian Nordic Reports Data from a Phase 3 Clinical Trial of its VLP-Based Chikungunya Virus Vaccine in Adults ≥65 Years of Age

• Study successfully met its primary endpoints
• Data from second pivotal Phase 3 study in people aged 12 to 64 years expected in the third quarter 2023

COPENHAGEN, Denmark, June 20, 2023 – Bavarian Nordic A/S (OMX: BAVA) announced today the initial safety and immunogenicity results from a randomized, double-blind, placebo-controlled Phase 3 clinical trial of a virus-like particle (VLP)-based chikungunya virus (CHIKV) vaccine candidate CHIKV VLP (PXVX0317) in healthy adults ≥65 years of age. Results from a second Phase 3 study evaluating the safety and immunogenicity of CHIKV VLP in healthy adolescents and adults 12 to 64 years old will report data during the third quarter of 2023.

A total of 413 participants were enrolled and randomized 1:1 to receive either a single intramuscular injection of CHIKV VLP or placebo. The initial results up to Day 22 post vaccination showed that CHIKV VLP was immunogenic in healthy adults ≥65 years of age, as demonstrated by a strong induction of CHIKV neutralizing antibodies in 87% of vaccinees with neutralising antibody titres exceeding the threshold agreed with authorities as a marker of seroprotection, thus meeting the primary endpoints of the study. Importantly, seroprotective neutralizing antibodies were also observed in the majority of the subjects (82%) at Day 15 post the single vaccination, clearly demonstrating a fast onset of protection for the VLP-based CHIKV vaccine candidate.

CHIKV VLP was well-tolerated in this older adult population and with similar rates of adverse events observed between the active and the placebo group. The trial will continue for a 6-month follow-up for both safety and immunogenicity.

Paul Chaplin, President and CEO of Bavarian Nordic said: “We are pleased to report the first Phase 3 results for our CHIKV vaccine candidate that clearly show this vaccine is well tolerated and highly immunogenic in an older adult population. They also match what has previously been reported for younger adults in an earlier Phase 2 study, including a fast onset of protection. While we still await the results from the second and larger Phase 3 study in adolescents and adults later this year, these highly encouraging results provide a high degree of confidence for our CHIKV vaccine program.”