Osivax, a Lyon-based biopharmaceutical company, announced on June 5, 2025, that all participants have completed their final visits in a Phase 2a clinical booster trial evaluating OVX836, the company's broad-spectrum influenza A vaccine candidate. The milestone marks a significant step forward in developing long-term influenza protection strategies, with final results expected in the second half of 2025.
Novel Approach to Influenza Prevention
OVX836 represents a first-in-class influenza A vaccine candidate that targets the nucleoprotein (NP), a highly conserved internal antigen. Unlike traditional vaccines that target surface antigens, the nucleoprotein is much less likely to mutate, potentially providing broader and more universal immune response. The vaccine utilizes Osivax's proprietary oligoDOM™ technology, which enables the design and production of a recombinant version of the nucleoprotein that self-assembles into nanoparticles, triggering powerful T-cell and B-cell immune responses.
Trial Design and Patient Population
The single-center, randomized, double-blind Phase 2a clinical trial (NCT06582277) is being conducted at the Center for Vaccinology (CEVAC) at Ghent University Hospital in Belgium. The study evaluates the immunogenicity and safety of a single intramuscular dose of OVX836 administered at either 180μg or 480μg.
The trial enrolled 117 healthy adults aged 20-64 who previously participated in Osivax's Phase 2 trials conducted 3 and 5 years ago (NCT04192500 or NCT05060887). These participants had previously received either OVX836 at various doses (180μg, 300μg, or 480μg), Influvac® Tetra, or placebo. Participants who had previously received placebo or Influvac® Tetra now serve as controls and received the highest dose of OVX836 (480μg) as primary vaccination.
Clinical Significance and Expert Perspectives
"Reaching the Last Patient Last Visit in this booster trial is a significant milestone for both our team and the field of influenza vaccine development," commented Prof. Isabel Leroux-Roels, Principal Investigator at CEVAC and Associate Professor at Ghent University. "This study offers the opportunity to investigate both primary and booster responses to a novel influenza vaccine over an extended time period."
Dr. Nicola Groth, Chief Medical Officer of Osivax, emphasized the trial's unique characteristics: "This trial is unique in that it assesses for the first time the immune response to a booster dose administered several years after initial vaccination. The insights gained will help us understand the persistence and boostability of immune response offered by OVX836, which is essential in our goal to develop a truly broad-spectrum flu vaccine."
Development Progress and Future Outlook
OVX836 has undergone extensive clinical testing, having been evaluated in seven clinical trials involving 1,400 participants. The vaccine candidate has demonstrated promising safety, immunogenicity, and efficacy outcomes in previous studies. The current booster trial represents a critical step in understanding the long-term immune response and durability of protection offered by this novel vaccine approach.
Osivax's broader ambition extends beyond influenza, with plans to develop a pan-respiratory virus vaccine capable of preventing all strains of influenza and all variants of COVID-19 in a single shot. The company aims to expand into other infectious disease indications through combinations and collaborations worldwide, leveraging its oligoDOM™ nanoparticle platform technology to develop transformative vaccines that generate superior T-cell responses alongside strong and sustained B-cell responses.
