Intercept Bio: Towards a nasal spray to prevent viral respiratory infections

Intercept Bio is a recently created spin-off founded jointly by UCLouvain and UNamur. Its ambition is to develop an innovative nasal spray designed to intercept respiratory viruses at one of the earliest stages of infection, when they attach to human cells.

The project emerged from a unique interuniversity collaboration that brought together complementary areas of expertise. At UCLouvain (LIBST), David Alsteens is head of the NanoBiophysics lab, which investigates the molecular mechanisms governing critical events at the cell surface, such as viral binding. Using atomic force microscopy (AFM), his team can image and measure interactions between viruses, molecules and cells at the nanoscale. At UNamur (NARILIS/NISM), Stéphane Vincent leads a research group specializing in bio-organic chemistry and glycosciences, with expertise in the design and synthesis of complex glycoconjugates.

The concept arose during the Covid-19 pandemic. In 2020, David Alsteens' team used AFM to investigate how SARS-CoV-2 attaches to human cells. This work highlighted the role of sialic acids, sugar residues found on the cell surface that can serve as binding sites for viruses.

Based on these findings, David Alsteens and Stéphane Vincent worked together to develop 9-Ac-SAP, a molecule bearing sialic acids and acting as a “decoy” to intercept viruses before they can attach to human cells. Instead of binding to the cell surface, the virus first encounters the molecule, which disrupts its adhesion and limits its ability to initiate infection.

In vitro studies have demonstrated the antiviral activity of this compound against SARS-CoV-2, influenza viruses and respiratory syncytial viruses (RSV). Encouraging results have also been obtained in mouse models, with efficacy observed in 80% of cases.

Rather than targeting a specific virus, the technology focuses on a mechanism shared by several respiratory viruses: their initial attachment to host cells. This paves the way for the development of a broad-spectrum preventive approach against multiple respiratory viruses, including emerging ones.

With the establishment of Intercept Bio, the project is progressing to the next stage: developing the technology as a nasal spray and conducting clinical trials in humans. The transition from fundamental research to this promising application is supported by the WEL Research Institute, UNamur Venture, and Sopartec.