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Advancing a SARS-CoV-2 antigen test
CAMBRIDGE & WETHERBY, U.K.—Avacta Group plc recently announced a collaboration with the Liverpool School of Tropical Medicine (LSTM) to clinically validate the rapid, saliva-based point-of-care (POC) coronavirus antigen test Avacta is developing with Cytiva.
“[This] is an important partnership which provides Avacta with access to patient samples both in the U.K. and abroad, where the incidence of the disease is currently much higher, to ensure prompt access to a sufficient number of samples for clinical validation,” stated Dr. Alastair Smith, CEO of Avacta. “We have been working with the Liverpool School of Tropical Medicine for some time to define the target performance specifications of the saliva-based rapid test and their insight has been tremendously helpful in this regard.”
LSTM was founded in 1898 as the first institution in the world dedicated to research and teaching in tropical medicine. LSTM has a research portfolio of around £320 million, with projects and partnerships in over 70 countries.
“The partnership between Avacta and LSTM exemplifies the role of the LSTM in translational work to advance products to market, and we are pleased to be working with Avacta on this coronavirus antigen test,” added Dr. Lisa Baldwin, business development manager, LSTM.
Under the terms of the collaboration, LSTM will carry out the clinical validation of the Avacta COVID-19 antigen rapid saliva test in their category 3 laboratories on patient samples. In addition to working with the UK government’s CONDOR program—which provides Avacta with access to patient samples in the United Kingdom—the partnership with LSTM provides the opportunity to access patient samples in Africa and South America. The higher prevalence of the disease in these regions means that samples for prospective clinical validation studies are more readily available.
“LSTM has access to real patient samples in Africa and South America where disease prevalence is much greater,” notes Smith. “This provides better access to a greater number of real samples to validate the tests, which will help speed up the process.”
Clinical validation generates the sensitivity and specificity performance parameters used to define the performance of a diagnostic test. LSTM is evaluating the performance of prototype lateral flow tests provided by Cytiva alongside Avacta’s ELISA laboratory test, using SARS-CoV-2 coronavirus samples, as a precursor to full clinical validation studies.
“The main advantage of the antigen test under development with Cytiva is that this [is] a POC test to determine whether you have the infection right now—so [it] could replace the slower PCR tests that are done on nasal swabs that have to be sent away to labs for testing,” Smith says. “It is different from other rapid tests that detect antibodies in your blood that are raised by your body over a period of a couple of weeks after infection. In the early stages of infection, the antibody tests would not give a positive result, but the Avacta/Cytiva antigen test would.”
“Compared with PCR tests, the test result can be delivered in a few minutes, which means that appropriate actions can be taken immediately as a result: e.g., a patient with a positive sample can isolate themselves immediately reducing potential transmission of the virus,” points out Smith. “A secondary advantage is the cost of the test and the testing process, with this test being much less expensive than laboratory tests and not requiring logistics to transfer samples, or a laboratory to run the test. We intend that ultimately the test will also be available to consumers, which is not really possible for PCR-based tests.”