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UK's DnaNudge Prepares Cartridge-Based PCR Test for COVID-19 Testing

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NEW YORK – British direct-to-consumer testing firm DnaNudge is pivoting to the clinical market with the development of a new point-of-care assay for SARS-CoV-2, the virus that causes COVID-19. The UK Department of Health and Social Care has already ordered 10,000 RNA test cartridges from the company, which expects to obtain a CE-IVD mark for its test within weeks.

London-based DnaNudge rolled out its platform at the end of last year, initially focusing on consumer applications like nutrition. Customers could supply a cheek swab and, after genotyping on the firm's handheld NudgeBox analyzer, would be guided in making dietary decisions with the use of a smartphone application or special wristband for scanning barcodes at partner supermarkets in the UK.

The company currently employs around 60 people and maintains a retail shop (temporarily closed due to the lockdown) in London's Covent Garden district.

"The whole idea of the test is to provide a genetic profile of your medical condition risks, particular to diabetes and obesity, and then relate that to nutrition and food, and, as a result, you could nudge people to eat healthier and it was actionable," said CEO Chris Toumazou. "When the COVID-19 pandemic came in, it just struck me that it would be so simple to adapt, to detect the RNA of the virus," he said. "Rather than looking at SNPs in human DNA, and looking at biomarkers, we could just look at the RNA of the virus."

Toumazou helped to develop the DnaNudge technology at Imperial College London, where he is a professor of engineering. The core platform was created within Imperial's Institute of Biomedical Engineering, and is based on innovations in biochemistry microfluidics, electronic circuits, as well as miniaturization based on smartphone technology. TTP, a technology development firm based in Cambridge, also contributed to product development. Toumazou cofounded the firm to commercialize the technology in 2016.

The firm's resulting NudgeBox analyser enables both DNA extraction and real-time PCR amplification. Following lysis and solid DNA extraction, the sample moved to an array, where 72 amplification reactions are carried out.

Two perceived strengths of its technology are the fact that it is a lab-free PCR test, meaning it requires no sample preparation, so users can run the test based on a simple swab from someone potentially infected with SARS-CoV-2. Also, because samples are run on the internal, 72-reaction array, DnaNudge's platform can multiplex, which has enabled the firm to integrate a control into its COVID-19 test.

"The chip has a huge multiplex of wells, so not only do we have US Centers for Disease Control and Prevention or World Health Organization primers for COVID-19, we can have as many commercial or Public Health England primers on there as we like," said Toumazou. "We have great coverage of the actual sequence of the virus," he said. "That was really important for us."

Regarding the control, it allows users to gauge the quality of the swab, arguably lessening the possibility of a false negative result. "A lot of the time, people are getting negative results when actually the swab is invalid," said Toumazou. "Having that control is really a big differentiator."

DnaNudge worked with partners at Imperial College School of Medicine and St. Mary's Hospital to trial the test using 400 patients suspected of having COVID-19. Another 200 patients at John Radcliffe Hospital in Oxford were run on the platform. Toumazou said the results "looked good" with sensitivity of between 97 percent and 99 percent, and specificity of 100 percent. Based on that performance, the UK's Medicines and Healthcare Products Regulatory Agency gave DNANudge a derogation to offer the test clinically in the UK, though it is near obtaining a CE-IVD mark to sell the test across Europe.

Validation studies continue, and Toumazou said the company expects another large order of between 10,000 and 20,000 cartridges from the UK Department of Health and Social Care. The test – which costs about £15 ($19) to £20 per cartridge – is not being positioned as an alternative to real-time PCR, which has emerged as the main testing platform for SARS-CoV-2 in Europe, but rather as a technology for use in "niche but important applications," such as triaging patients in emergency departments to determine if they are positive for the virus or not, or in maternity wards, to see if mothers going into labor have the virus.

"Another big field is asymptomatic healthcare workers, because they are the ones who could be infectious and working with patients of high risk," said Toumazou. "These areas are important for this type of point-of-care test."

Going forward, DnaNudge envisions its test being used for screening people coming out of quarantine, or during travel at airports or train stations. "Once we get the CE-IVD mark, we'll start going into the public sector, care homes, police stations, and airports," said Toumazou. "That will allow us to expand quite rapidly into those areas," he said. "Those will be the most important as we start coming out of lockdown."

Because of its multiplexing capabilities, the company could fold the test into a larger panel once the next flu season starts. "It will be easy for us to put on the same multiplex, influenza A, influenza B, and coronavirus," said Toumazou.

Dozens of firms are developing handheld platforms for SARS-CoV-2, or near-patient systems. These include Mesa Biotech, Cepheid, MolBio Diagnostics, Hibergene, Coyote Bioscience, Mobidiag, and many others. One such firm, Austin, Texas-based Nuclein, has developed a disposable handheld real-time PCR system and prototype for SARS-CoV-2. Called the Nuclein Hand-Held PCR Test, the battery-powered system provides results in less than one hour. Nuclein said earlier this month that it is seeking partners to commercialize its product.

Though he acknowledged the competition, Toumazou noted DnaNudge's experience as a consumer-facing company with giving it a different approach to the market. "I think one of the big differences between this technology and some of the other point-of-care technologies is that it absolutely doesn't need any manual step," said Toumazou. "When we ran it in the consumer environment, it had to be consumer friendly. We didn't want the white coats, and the pipettes, and the labs," he said. "Everything is contained."

As it awaits its CE-IVD mark, and perhaps another large order, DnaNudge is currently scaling up manufacturing too. Each NudgeBox can run about 350 tests per week, meaning that with 2,000 analyzers, the firm could support a million tests per week. By the end of May, the company hopes to have about 300,000 cartridges ready for use, Toumazou noted. The firm outsources manufacturing of its products to global manufacturers.

The firm hasn't taken its eye off the consumer sector either, though it's currently focused on COVID-19. Toumazou said that in addition to its new foray into infectious disease testing, DnaNudge will continue developing tests for the consumer market in the future.

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