On July 22, 2025, Sanofi announced a definitive agreement to acquire Vicebio, a clinical-stage biotechnology company developing next-generation respiratory vaccines. The deal is valued at $1.6 billion and includes a $1.15 billion upfront payment with up to $450 million in milestone-based payments. The acquisition aims to expand Sanofi’s respiratory vaccine portfolio through access to Vicebio’s proprietary Molecular Clamp technology.
Vicebio, based in London, focuses on targeting severe respiratory viruses like RSV and hMPV. Its lead asset, VXB-241, is currently undergoing exploratory Phase 1 trials.
Molecular Clamp technology brings unique advantages
Vicebio’s platform is built around the Molecular Clamp, a protein-stabilizing technology originally developed at the University of Queensland. This technology stabilizes viral surface proteins, enhancing the body’s immune response and allowing production of liquid-form, multivalent vaccines that are easy to store and deliver.
The Molecular Clamp platform works across a broad range of viruses, including RSV, hMPV, parainfluenza viruses, influenza, and coronaviruses. Its adaptability and manufacturing benefits make it a strategic fit for Sanofi’s growing vaccine pipeline.
Vicebio’s lead vaccine shows early promise
Vicebio’s main product candidate, VXB-241, is a bivalent vaccine designed to protect against both RSV and hMPV. These viruses are known to cause severe respiratory illnesses in older adults and individuals with weakened immune systems.
VXB-241 is currently in exploratory Phase 1 clinical trials. Interim results show the vaccine has a favorable safety and tolerability profile in adults aged 60 and older. The study is ongoing and continues to gather safety and immunogenicity data.
Global investment backed Vicebio’s clinical expansion
In September 2024, Vicebio raised $100 million in Series B funding. The round was led by TCGX and included participation from Life Sciences at Goldman Sachs Alternatives, Avoro Ventures, venBio Partners, UniQuest, and Medicxi.
This funding allowed Vicebio to accelerate the development of VXB-241 and advance next-generation vaccine candidates using the same technology platform.
Leaders from both companies share their vision
Giovanni Mariggi, Chairman of Vicebio and Partner at Medicxi, stated that the company was created with the goal of developing best-in-class respiratory vaccines. He emphasized the team’s strong collaboration with investors and researchers at the University of Queensland.
Cariad Chester, Managing Partner at TCGX, said Vicebio’s multivalent vaccines could protect millions from life-threatening infections. She expressed confidence in Sanofi’s ability to advance the vaccines to global markets.
Vicebio CEO Emmanuel Hanon called the deal a major step toward global public health impact. He highlighted the team’s dedication to innovation and its focus on combining deep scientific knowledge with practical applications.
Sanofi strengthens vaccine pipeline with platform acquisition
The acquisition of Vicebio aligns with Sanofi’s strategy to boost its vaccine capabilities, particularly in respiratory health. By integrating the Molecular Clamp platform, Sanofi aims to accelerate development of multivalent vaccines targeting multiple respiratory viruses in a single shot.
This deal also demonstrates Sanofi’s commitment to using advanced R&D technologies and partnerships to expand its reach and address urgent global health challenges.
FAQs
What is Vicebio’s main vaccine candidate?
Vicebio is developing VXB-241, a bivalent vaccine that targets RSV and hMPV. It is currently in Phase 1 clinical trials and has shown early signs of safety and tolerability in older adults.
What is Molecular Clamp technology?
It is a protein-stabilizing method that helps maintain the natural shape of viral surface proteins. This triggers a stronger immune response and supports the creation of multivalent vaccines in liquid form.
Why is Sanofi acquiring Vicebio?
Sanofi wants to expand its respiratory vaccine portfolio and access new vaccine technology. Vicebio offers both a promising RSV-hMPV vaccine and a scalable platform for other respiratory viruses.
How much is the acquisition deal worth?
Sanofi will pay up to $1.6 billion for Vicebio. This includes $1.15 billion upfront and $450 million in future milestone payments.
Who funded Vicebio’s development so far?
Vicebio’s Series B funding round was led by TCGX and supported by Goldman Sachs Alternatives, Avoro Ventures, venBio, UniQuest, and Medicxi.
