On Jul. 22, 2025, Sanofi announces it has entered into an agreement to acquire Vicebio, a privately held biotechnology company headquartered in London, UK. The acquisition brings an early-stage combination vaccine candidate for respiratory syncytial virus (RSV) and human metapneumovirus (hMPV), both respiratory viruses, and expands the capabilities in vaccine design and development with Vicebio’s ‘Molecular Clamp’ technology.

Under the terms of the agreement, Sanofi would acquire all of Vicebio’s share capital for a total upfront payment of $1.15 billion, with potential milestone payments of up to $450 million based on development and regulatory achievements. The transaction is expected to close in Q4 2025, subject to customary closing conditions, including receipt of regulatory approvals. The acquisition will not have a significant impact on Sanofi’s financial guidance for 2025.

The vaccine candidate complements Sanofi’s position in the respiratory vaccines space where the company is present in flu and RSV prevention. It allows Sanofi to offer increased physician and patient choice in RSV and hMPV by adding a non-mRNA vaccine to its pipeline.

In addition, the acquisition adds ‘Molecular Clamp’, an innovative technology that stabilizes viral proteins in their native shape, enabling the immune system to recognize and respond to them more effectively. This approach enables quicker development of fully liquid combination vaccines that can be stored at standard refrigeration temperatures (2–8°C), eliminating the need for freezing or freeze-drying, thereby simplifying manufacturing and distribution. Furthermore, fully liquid vaccines can be made available in prefilled syringes, enhancing ease of use, safety, and operational efficiency across healthcare settings.