Update on AffiDX SARS-CoV-2 antigen lateral flow tests from Avacta

Avacta Group plc, a clinical stage biopharmaceutical company developing innovative cancer therapies and powerful diagnostics based on its proprietary Affimer^® and pre|CISION™ platforms, provides an update on the performance of the AffiDX^® SARS-CoV-2 antigen lateral flow test (LFT) with the Omicron variant.

The performance of all rapid antigen tests has come under recent scrutiny in light of the large number of mutations in the Omicron variant of the SARS-CoV-2 virus and the US Food and Drug Administration, as well as other sources, has indicated that antigen tests generally will detect the Omicron variant but may have reduced sensitivity.¹

As reported on 15 December 2021, the AffiDX^® SARS-CoV-2 antigen test has been shown to detect the Omicron variant of the SARS-CoV-2 virus in patient samples in a small clinical study. Whilst the AffiDX^® antigen test is effective at identifying high viral loads of Omicron, further laboratory analysis carried out by Avacta indicates that the sensitivity of the test is reduced at lower viral loads when compared with the sensitivity of the AffiDX^® test with previous SARS-CoV-2 variants.

The AffiDX^® SARS CoV-2 antigen lateral flow test contains both a proprietary Affimer^® reagent and a commercially available antibody. The data shows that the Affimer^® reagent in the AffiDX^® test detects the Omicron variant with the same sensitivity as the Delta variant, and it is the performance of the antibody, with which the Affimer^® is paired in the test, that has been affected by the additional Omicron mutations. Avacta has therefore independently taken the decision to pause sales of the AffiDX^® antigen test whilst it replaces the antibody in the product to ensure that its performance with the Omicron variant matches the high performance with previous mutations.

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References:

U.S. Food and Drug Administration. 2022. SARS-CoV-2 Viral Mutations: Impact on COVID-19 Tests. [online] Available at: SARS-CoV-2 Viral Mutations: Impact on COVID-19 Tests | FDA