Avacta Group plc (LON:AVCT), the developer of Affimer® biotherapeutics and reagents, has today announced that several of the Affimer reagents recently generated for development of a point-of-care COVID-19 antigen saliva test have now also been shown to block the interaction between the virus’ spike protein and ACE2, a receptor on human cells that is key to the virus infection pathway1.
Avacta has already successfully generated a large number of Affimer reagents that bind to the SARS-COV-2 virus’ spike protein as part of its partnership with Cytiva (formerly GE Healthcare Life Sciences and now part of Danaher Corp). As previously announced, Avacta and Cytiva are working together to develop a rapid point-of-care COVID-19 antigen saliva test to be mass produced for large-scale population screening and for self-testing by consumers.
Further work at Avacta2 has now shown that several of these Affimer reagents block the interaction between the virus’ spike protein and a receptor found on human cells, called ACE2, to which the virus spike protein binds in order to infect cells. Affimer reagents that block the binding of the virus spike protein to ACE2 therefore have the potential to prevent infection and act as “neutralising” therapies.
Neutralising therapies could be given to those exposed to the virus (such as health and social-care workers) to prevent infection, as well as to patients already infected by the virus, to help treat and prevent disease progression.
Large pharmaceutical companies, such as AstraZeneca and GSK, are now starting programmes to develop neutralising antibodies in an attempt to block the SARS-COV-2 spike protein’s interaction with ACE2. Avacta has now demonstrated that several Affimer reagents also perform this blocking function and the Company is now seeking a partner that has the resources available to develop a neutralising Affimer therapy as quickly as possible.
Dr Alastair Smith, Chief Executive Officer of Avacta Group, commented:
“This is a very exciting development in the COVID-19 programme. It only took four weeks to generate more than fifty Affimer reagents that bind the SARS-COV-2 virus spike protein and amongst those we now know that there are neutralising Affimers that block the interaction with a key human cell surface receptor, raising the potential for a therapy to prevent infection.
Recently GSK invested $250 million in Vir Biotechnology Inc3 to develop potential antibody treatments for COVID-19 by selecting antibodies from recovered patients, and AstraZeneca also recently announced that it would start a programme to find new monoclonal antibodies that block the spike/ACE2 interaction4.
There is significant potential for a therapy that could help prevent infection and limit the progression of the disease, providing immediate benefit to patients. With a large and well-resourced partner, a neutralising Affimer therapy could potentially be developed more quickly than a vaccine and we believe that the likelihood of success would be high.
I look forward to updating the market further on this and on the development of a COVID-19 antigen rapid saliva test with Cytiva which continues apace.”
1. https://www.sciencedirect.com/science/article/pii/S0092867420302294
2. Avacta has carried out competition ELISA measurements (enzyme linked immunosorbent assay) which show that several Affimer reagents disrupt the binding of ACE2 to the SARS-COV-2 S1 spike protein with a range of different potencies.
