Osivax has vaccinated the first participant in a randomized, double-blind, multicenter phase 2b clinical trial (NCT05569239) evaluating OVX836, a broad-spectrum influenza A vaccine candidate. The study will assess efficacy, safety, and immunogenicity during the upcoming flu season.
The trial plans to enroll approximately 2,850 adults aged 18–59 at 16 sites across multiple European countries. Participants will be randomly assigned under blinded conditions, and outcomes will include laboratory-confirmed influenza as well as prespecified immunologic endpoints.
OVX836 targets the influenza A nucleoprotein (NP), a conserved internal antigen intended to broaden protection across strains. The candidate employs Osivax’s oligoDOM™ platform to present NP as a self-assembling nanoparticle designed to elicit robust T-cell and B-cell responses.
In an email Q&A with the Osivax team, we discussed the phase 2b trial and development plans. They discussed endpoints, breadth/durability, and potential US use.
Contagion: What is the primary efficacy endpoint and case definition (e.g., PCR-confirmed symptomatic influenza A), how is the study powered, and how will safety and immunogenicity be assessed alongside efficacy?
Osivax team: "The primary efficacy endpoint is defined as first occurrence of RT-PCR-confirmed influenza Type A symptomatic disease with a protocol-defined case definition.:
"The study will have 80% power to demonstrate a vaccine efficacy of 50% with a lower limit of the 95% confidence interval superior to 0%, taking into account an attack rate of 3.8% in the placebo group."
"The vaccine safety will be assessed in all participants through solicited local and systemic adverse events within 7 days after vaccination, unsolicited adverse events up to Day 29, serious adverse events (SAEs), adverse events of special interest (AESIs), new onset of chronic diseases (NOCDs), and medically attended adverse events (MAAEs) throughout the entire study (up to 10 months). The immune response will be assessed in a subset of 56 participants using blood samples collected at Day 1 (pre-vaccination) and Day 8. These assessments will include cell-mediated immune response measured by ELISPOT assay for IFN-γ secretion by PBMC, Flow cytometry (ICS) for NP-specific CD4+ and CD8+ T-cells expressing IL-2, TNFα, and/or IFNγ, and finally the humoral immune response measured by ELISA to quantify anti-nucleoprotein IgG levels in serum."
