Shares of Wetherby-based cancer therapies and diagnostics company Avacta Group plc rose another 8% on Tuesday after it announced positive data from the clinical validation of its AffiDX SARS-CoV-2 antigen lateral flow test.

“Data from the clinical study conducted in Europe on 98 positive Covid-19 samples demonstrate excellent performance in identifying the SARS-CoV-2 virus across a broad range of viral loads,” said Avacta.

“These data will now be combined with stability and other performance data from ongoing studies to finalise the technical file for CE marking the AffiDX SARS-CoV-2 antigen lateral flow test for professional use, allowing the company to begin commercial roll-out in Europe in May.”

Avacta Group shares have soared more than 300% in the past 12 months amid its work on Covid-19 tests to give it a current stock market value of around £600 million.

The company added in a stock exchange statement on Tuesday: “The clinical evaluation of Avacta’s lateral flow test was carried out at a single site in Europe with patient samples with viral loads confirmed by PCR.

“The study tested 98 positive samples (31 with Ct<26; 65 with Ct 26-30 and 2 with Ct 30-31).

“Avacta’s rapid antigen test identified 96/98 of these correctly as positive with a 20 minutes read time resulting in a clinical sensitivity of 98.0% for samples within this broad range down to low viral loads.

“Out of a total of 102 negative samples tested with the lateral flow device, the test correctly identified 101 as negative, giving a clinical specificity of 99.0%.

“Lateral flow rapid antigen tests are intended to provide a low cost means of identifying individuals with a high viral load that means they are more likely to infect others.

“Many factors affect whether an individual will infect others or not, as well as viral load, such as the circumstances and length of exposure.

“However, there is a growing consensus that a viral load as measured by PCR of Ct<27 should be considered as infectious.

“The clinical data for Avacta’s AffiDX SARS-CoV-2 antigen lateral flow test demonstrated 100% sensitivity for identifying infectious individuals in this range.”

Dr Alastair Smith, CEO of Avacta Group, said: “I am delighted with the clinical data from this larger clinical study, which has robustly evaluated the AffiDX antigen test with lower viral loads of Ct>26 as well as with higher viral load samples.

“The results are very impressive and marks a major step in obtaining a CE mark for professional use.

“As part of the study the same clinical samples were tested with two leading, commercially available lateral flow antigen tests, and the data show that the AffiDx test had better clinical sensitivity across the range of Ct value and in particular at lower viral loads.

“We are completing the necessary assessment of the product from our manufacturing partner Global Access Diagnostics, including stability testing that will complete the technical file for CE marking, which we expect will happen in early May.

“We are very excited by the potential of this high quality SARS-CoV-2 rapid antigen test and we are looking forward to updating the market as we commercially roll-out the AffiDX test in the coming months.“