Flu vaccine trial fails to meet efficacy goal

In a randomized, placebo‑controlled Phase 2b trial in Belgium, France, Finland and Germany, Osivax’s candidate OVX836—an oligoDOM nanoparticle vaccine targeting the conserved nucleoprotein—was given to 2,850 healthy adults aged 18 to 59. The study reported a point‑estimate vaccine efficacy of 24 % against laboratory‑confirmed influenza, which fell far short of the pre‑specified 50 % target and was not statistically significant. Secondary analyses showed 28 % efficacy against CDC‑defined influenza‑like illness, 27 % against A/H3, and 25 % against A/H1N1pdm09. Despite the modest efficacy, the vaccine had a favourable safety profile and induced robust antibody and T‑cell responses to the nucleoprotein.

Because the trial did not meet its primary endpoint, Osivax is now focusing on combining OVX836 with existing seasonal flu vaccines. The company has entered agreements with South Korea’s GC Biopharma and an unnamed global partner to develop a single‑injection product that blends OVX836 with a conventional vaccine. Osivax plans to progress these combination candidates through further efficacy studies, with no timeline yet announced for a next‑phase trial.