Sanofi $1.6 billion acquisition to advance respiratory vaccines

Sanofi has agreed to acquire the biotech Vicebio for an upfront payment of $1.15 billion, supporting the advancement of respiratory virus vaccines.

In addition to the initial payment, Sanofi will pay up to $450 million, subject to achieved development and regulatory milestones.

The deal intends to expand capabilities in vaccine design and development and will enable Sanofi to add a non-mRNA vaccine to its development pipeline.

Specifically, the new agreement involves a combination vaccine candidate to immunise against both respiratory syncytial virus (RSV) and a human metapneumovirus (hMPV).

Advancing vaccine design through Sanofi’s acquisition of Vicebio

This acquisition by Sanofi adds ‘Molecular Clamp’ technology, which stabilises viral proteins in their native shape, enhancing the immune system’s ability to respond to these proteins.

This innovative approach provides a shorter development timeline for fully liquid combination vaccines stored at standard refrigeration temperatures (2–8°C). This removes the need for freezing or freeze-drying and simplifies manufacturing. There is also capability for fully liquid vaccines to be administered via prefilled syringes, making them safer and easier to use, Sanofi explained.

Vicebio’s pipeline includes VXB-241, a bivalent vaccine candidate, currently being evaluated in a Phase I study in older adults to protect against RSV and hMPV. The products in development are intended to offer broad protection and have high manufacturability, Vicebio shared on its website.  

“This acquisition furthers Sanofi’s dedication to vaccine innovation with the potential to develop next-generation combination vaccines that could provide protection to older adults against multiple respiratory viruses with a single immunisation,” explained Jean-François Toussaint, Global Head of Research and Development Vaccines at Sanofi.

The transaction between Sanofi and Vicebio is expected to close in the final quarter of 2025, subject to customary closing conditions.