Osivax’s flu vaccine OVX836 misses primary efficacy goal in phase 2b trial

Osivax announced that its influenza A vaccine candidate OVX836 failed to meet the primary efficacy endpoint in a phase 2b trial involving 2,850 healthy adults in Europe.

The trial showed a vaccine efficacy of 24%, well below the pre‑specified 50% threshold. Secondary analyses suggested modest signals, with strain‑specific efficacy estimates ranging from 25% to 28% for A/H3 and A/H1N1pdm09.

Safety was acceptable, and the vaccine generated strong nucleoprotein‑specific antibody and T‑cell responses. Osivax highlighted these immune findings as the first consistent efficacy signal for a monovalent nucleoprotein‑based flu vaccine.

The company said it will reassess its development strategy, focusing on combination approaches rather than a standalone product.