Respiratory syncytial virus (RSV), human metapneumovirus (hMPV) and parainfluenza virus 3 (PIV3) are medically important causes of respiratory tract infections. Combined these three viruses cause more severe disease and hospitalisations than influenza viruses. After more than 5 decades of unsuccessful research and development, vaccines have recently been approved for the prevention of lower respiratory tract disease caused by RSV, however vaccines for hMPV and PIV3 remain in early-stage development. The game changing development which lead to effective RSV vaccines has been discovery of methods to stabilize the RSV fusion glycoprotein (F) into the elusive prefusion conformation (preF).
The University of Queensland has developed a broadly applicable proprietary technology (molecular clamp), to facilitate preF stabilization not only for RSV but also hMPV and PIV3, and a diverse array of fusion glycoproteins from other viral families. In association with biotech spinout company, Vicebio Ltd, our team have identified lead candidate subunit vaccines for RSV, hMPV and PIV3, all of which have demonstrated, high yield, high stability and the ability to effectively elicit strong neutralizing immune response in animal models. The bivalent vaccine against RSV and hMPV (VXB-241) entered a phase I clinical trial in August 2024 and the trivalent formulation which also includes PIV3 (VXB-251) is completing pre-clinical development.
With three separate respiratory virus vaccines currently recommended for elderly populations (seasonal influenza, COVID-19 and RSV), the prospect of adding further vaccines for other high burden respiratory viruses such as hMPV or PIV3 into the schedule becomes problematic. Vicebio seeks to overcome this problem through the production of highly protective, multivalent vaccines in ready-to-use, liquid-stable formulations.