Prototype saliva test for Covid-19 ‘ready in weeks’ after Avacta ships Affimer reagents to Cytiva
Hopes that a new prototype saliva test for Covid-19 will be ready within weeks after Avacta shipped reagents that will be used to detect the virus.
The Whittlesford-based life science company has used its Affimer platform to generate multiple, highly specific reagents that bind to the SARS-CoV-2 viral antigen, and which do not cross-react with SARS, MERS and other closely-related coronaviruses.
Cytiva, formerly GE Healthcare Life Sciences, will use these Affimer reagents to develop its point-of-care Covid-19 saliva test strip for CE marking in Europe and FDA approval in the United States.
Avacta announced on Monday that it had manufactured and shipped sufficient quantities of the Affimer reagents for test development.
And it has announced today (Friday) that several of its the reagents generated for the antigen saliva test have 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 pathway.
Avacta is also providing the reagents to Adeptrix, in Massachusetts, with which it will be developing a Covid-19 laboratory test to run on mass spectrometers using the US company’s proprietary bead-assisted mass spectrometry (BAMS) assay platform.
Further testing has shown there are Affimer reagents that can work in pairs, with both binding to the virus’ spike protein at the same time.
It means a test could detect an intact virus particle as well as spike proteins that have become separated from the virus particle during the development of the Covid-19 disease, which could be key to monitoring disease progression.
Cytiva and Avacta hope to develop rapid test strips for the detached spike protein and the intact virus particle, aiming to have prototype devices ready “in a few weeks”.
Adeptrix is working on a similar timescale to develop its prototype BAMS test.
Both tests would indicate if someone has a Covid-19 infection at the time of testing.
Avacta CEO Dr Alastair Smith said: “I am delighted that the Covid-19 antigen test development programme continues ahead of schedule and we are today shipping the Affimer reagents to our partners to begin test development.
“It is a major accomplishment to have generated Affimer reagents that can work in pairs as well as singly, as this opens up the potential for detecting the detached spike proteins as well as the intact virus particles, which means that we should have the best possible Covid-19 antigen test.
“The need for rapid antigen tests to diagnose Covid-19 infection that can be mass produced for rapid, professional screening of large populations, and for self-testing by consumers themselves, is crucial to limiting and tracking the spread of this disease.
“Antigen testing will also be critical to lockdown exit strategies around the world in order to get healthy, non-contagious people back to work to reboot economies, and there will be an ongoing need for several years for antigen testing as the disease recurs.”
He added: “There has been considerable commercial interest in these reagents since we announced that we had successfully generated them.
“The group is very actively exploring further commercial opportunities to develop them with partners into diagnostic tests and with distributors to provide large scale routes to market for professional and home use.
“Another important step has been taken in delivering these tests to end users. I look forward very much to updating the market on further progress over the next few weeks.”
Avacta owns all the intellectual property relating to the Affimer reagents and retains all commercial rights.
The company’s collaboration with Adeptrix is designed to expand testing capacity in hospitals significantly.
Adeptrix’s proprietary BAMS platform will enrich the sample to improve sensitivity, while mass spectrometry will improve specificity.
It will mean a single technician could analyse hundreds of samples per day using BAMS, exceeding the capacity of a single PCR machine.
Hospitals around the world are not currently utilising their mass spectrometers for Covid-19 testing. Saliva, nasopharyngeal swabs or serum could be used for samples with this test.
Adeptrix and Avacta have confirmed they are in discussions with large-scale manufacturing partners to deploy the high throughput test once it is ready next month.
Avacta will receive a royalty based on sales of the BAMS test kits.
Dr Jeffrey C Silva, director of product development at Adeptrix, said: “I have worked with Affimers previously and have found them to be excellent immunoassay reagents, so we are looking forward to quickly implementing the SARS-COV-2 Affimers in a BAMS diagnostic test.
“Mass spectrometry can enhance the diagnostic utility of immunoassays, as it is capable of monitoring both existing and emerging viral strains by accurately measuring the molecular components of the virus. BAMS provides an ideal multiplexing platform to obtain higher specificity for monitoring Covid-19 infection.
Dr Smith said: “Jeff and his team are world-renowned in the mass spectrometry field, and the BAMS diagnostic platform is highly sensitive and specific, giving us great confidence that a high performance Covid-19 antigen test can be developed and launched commercially very quickly.
“We believe that the BAMS test will be hugely attractive as an adjunct to PCR testing because it uses laboratory equipment that is already in hospital labs but not currently used for Covid-19 testing so it provides incremental testing capacity.
“A consensus view is building around the world that hundreds of millions of Covid-19 tests are going to be required per month for a long period, and that the disease will be endemic after the initial pandemic has passed, meaning that testing for Covid-19 is going to be needed for many years.”
More by this authorPaul Brackley