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Intelligent Fingerprinting Adding SARS-CoV-2 Saliva Test to Portfolio of Drug-Testing Assays


NEW YORK – Intelligent Fingerprinting started with a premise that fit its name: performing drug screening tests using the sweat from a person's fingerprint.

But with reports of a potential fourth wave of the COVID-19 pandemic and the Delta variant spreading rapidly across the world, the British company is using its lateral flow technology to detect SARS-CoV-2 from saliva and add to its test portfolio.

The key difference between its drug tests and the SARS-CoV-2 test is that it's changed its specimen collection to saliva, Executive Chairman Philip Hand said. Its drug tests rely on sweat from fingerprints to detect the presence of illicit drugs, and the SARS-CoV-2 test is its first foray into other sample types.

As the trend in COVID-19 testing has become more focused on surveillance and screening testing, concerns about any loss in accuracy with saliva-based tests have been mitigated. A test originally developed by Thermo Fisher Scientific but modified by Rutgers University received the first Emergency Use Authorization from the US Food and Drug Administration for SARS-CoV-2 testing using saliva as a sample. Since then, numerous tests have received EUAs for use with saliva samples.

The ease of collecting saliva samples was a large driver in Intelligent Fingerprinting's decision to use it as a sample type, Hand said. Nasal swabs can be uncomfortable for both younger children and elderly people, he said, calling their collection a "distressing exercise." In addition, the collection process can be prone to errors when untrained individuals self-collect nasal samples.

Intelligent Fingerprinting's 20-minute test uses polyclonal antibodies to detect a SARS-CoV-2 antigen. Hand noted that it has also been effective in detecting variants of the disease, such as the South African and Delta variants. "Other mutations may present, but … as we stand, we've been able to identify those currently being seen," he said.

Using gold immunonanoparticle technology, the test enables visual detection of a bound antigen via a control line and a red line on the test strip when a sample is positive.

The test could be used at the point of care and suits itself particularly for use in schools and nursing homes, he added. The firm's strategy right now is to develop it for CE marking for professional use and then assess its potential for home use, Hand said. The firm is taking the regulatory journey "one stage at a time," and is "mindful that these things take a long time," he said.

Cambridge, UK-based Intelligent Fingerprinting has completed the development of the assay and is currently finishing its technical file for the CE mark, with a plan to have the test available to the European market by early fall. While the company is looking to eventually submit to the FDA for EUA, the "first thing we need to do is complete the technical file for us here in the UK and Europe and to get that CE mark on the product."

Part of the technical file it's submitting is a study looking at the test's performance on 150 RT-PCR confirmed positive clinical samples, where it had 100 percent sensitivity. When tested on 250 confirmed negative samples, it had 100 percent specificity with no false positives.

Additional data collection and trials will depend on "what the regulatory bodies call upon us to do as we go through those stages," although Hand said he "was quite confident" that the firm has enough data for CE marking for professional use.

The firm has a direct sales force that it will use to sell the COVID-19 test in the UK, and it will also work with distributors across Europe and the Middle East.

While it prepares the test for CE marking, Intelligent Fingerprinting is also preparing it for a European and UK regulatory landscape that is in flux.

Martin Payne, the company's director of quality assurance and regulatory affairs, said it has been in discussion with the firm's notified body, a standards organization designated by the EU, involving the transition from CE marking to IVD Regulation in the EU. The new regulations are set to come into effect on May 26, 2022, although experts have called for the implementation to be postponed.

Payne added that the technical file the firm is completing for CE marking will be updated to incorporate the transition and meet the new requirements.

Under the regulations, the majority of in vitro diagnostic tests will be cleared through the national bodies, rather than undergoing the self-certification process for CE marking.

As for the current confusion about the UK's regulatory pathway after separating from the EU, Payne said the firm is working to ensure that the regulatory pathway it's adopting is "fully aligned with all final requirements as they emerge."

New tests planned

The firm's main business thus far, however, uses conventional lateral flow technology to detect drugs of abuse from the sweat on someone's fingerprint. Its tests for these drugs have been on the market for around 18 months, Hand said.

Traditional drug tests use urine or saliva samples to determine the presence of a drug, he said. The issue with urine testing is that there are major opportunities for cross-contamination, although testing tends to be low-cost. As for saliva, it is viscous, which can make lateral flow devices difficult to run.

To use Intelligent Fingerprinting's test, a person's finger is pressed on the test pad for five seconds per finger, or 50 seconds total. The buffer clip on the self-contained, anti-tamper cartridge depresses and releases a solution to dissolve the print down to nitrocellulose, which is then put into the actual instrument for 10 minutes.

If the drug is present, a fluorescently tagged antibody specific to the drug will preferentially bind to the drug, resulting in a decrease in the fluorescence signal indicating its presence. The absence of a particular drug produces the maximum fluorescent signal.

The pass/fail result is put onto the instrument's screen and simultaneously printed and stored in the system for download if needed, Hand said.

The firm also has a proprietary methodology to collect the fingerprints and send them to a central laboratory for confirmatory testing using liquid chromatography with tandem mass spectrometry, Hand said. Similar to any point-of-care drug screening test, a positive result from the same sample needs to be confirmed with a lab test.

While testing for drugs of abuse has been the main focus, Hand said the firm plans to use its technology for many different diseases and has applications in serology, infectious disease, fertility, and oncology, all of which Intelligent Fingerprinting is pursuing individually and possibly with third-party organizations.

The firm is going to "try and widen the portfolio," he said. "Our main drive is to augment the work that we do in drugs of abuse with these other areas of medical diagnostics."

However, the firm isn't abandoning drug products. Starting in the fall, it will begin work on other tests intended to launch next year and in 2023, Hand said, including tests for specific drugs such as fentanyl or oxycodone. Part of the development involves determining the market for different tests.

Currently, it offers two four-drug panels in the UK and Europe: one for opiates, THC, cocaine, and amphetamines; and one for cocaine, opiates, methadone, and benzodiazepines. The drugs can be interchanged across the panels, Hand said. It has also spoken with the FDA about getting clearance for the tests, he said.

In a 2018 study published in the Journal of Analytical Toxicology, the company found that the technology could detect the presence of each drug and strongly correlated with follow-up LC-MS tests. Accuracy was 99 percent for THC, 96 percent for opiates, 95 percent for cocaine, and 93 percent for amphetamines compared to LC-MS testing.

The study noted that the test can't differentiate between someone who's used drugs of abuse and someone who's simply handled or accidentally encountered them, though this could be solved by having people wash their hands with soap and water and wait 10 to 15 minutes before collecting the sample.

More recently, a 2020 study published in Nature journal's Scientific Reports found that the company's test for cocaine had an accuracy, sensitivity, and specificity of 95 percent, 90 percent, and 100 percent, respectively.

Melanie Bailey, a professor in the department of chemistry at the University of Surrey, Guildford who co-authored the study, said the main benefit of the test is the ease of sampling, because it's "completely noninvasive."

One of the problems with fingerprint sampling in general is the difficulty providing quantitative measures of drug levels, rather than just a yes or no answer, Bailey said.

The most common use for Intelligent Fingerprinting's tests has been for workplace testing, particularly in safety-critical areas, such as transportation or construction. It is also selling the tests to drug dispensaries and clinics to check that patients are taking their prescriptions. The tests also lend themselves to criminal justice settings, Hand said.

Bailey echoed the sentiment, noting that there were "many possible opportunities" for this technology, namely for mass screening applications — particularly in workplaces, in prisons, and at borders.

The instrument is portable and costs around £2,500 ($3,492), while the four-panel cartridges retail for £12 ($17). Intelligent Fingerprinting is currently the only company offering fingerprint drug testing, although researchers, including Bailey, as well as scientists at the University of Surrey in the UK as well as at the Netherlands Forensic Institute have also studied the use of fingerprints in drug testing.

Bailey said she is currently working on "a number of projects" to expand the use of fingerprint testing beyond illicit drug monitoring, specifically detecting antipsychotic and antibiotic drugs.