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With Patch-Based Sample Collection, En Carta Dx Plans to Offer Molecular Early Lyme Testing


NEW YORK – Startup En Carta Diagnostics plans to help patients find out immediately following a tick bite whether they have been infected with Lyme disease-causing bacteria using a cartridge-based molecular test and a sample collection patch that is applied to the bite site.

The Paris-based firm is developing a 30-minute point-of-care test kit that incorporates loop-mediated isothermal amplification (LAMP) and aptamers with high binding affinity and specificity housed in a lateral flow assay. The test is being developed to detect Borrelia bacteria in an interstitial fluid sample, which would be drawn with a microneedle patch from the site of a tick bite within 48 hours of removing the tick.

The firm announced last week that it had secured €1.5 million ($1.6 million) in pre-seed funding that will help the company to develop and evaluate its Lyme disease test kit and implement a commercial strategy.

En Carta CEO Guillaume Horreard said that Lyme disease can be difficult to detect in a patient's blood during the first weeks following the initial infection, but various studies indicate that the bacteria can be detected at the tick bite site 12 to 48 hours following infection. He wants to make the firm's test kits available in pharmacies so they can be used during or immediately after a hike.

"What we've confirmed with a market study is that pharmacists, they see a lot of people who come back from a hike with a tick on them or their children, and they are wondering 'What should I do?'" he said.

Those patients often hear in response that they should wait for the appearance of a rash, he said.

"The goal is to contact a telehealth provider, for instance, so that we could send them the results and make a complete experience for the patient," he said.

About three quarters of people with Lyme disease will develop the characteristic erythema migrans rash that can be used by healthcare providers to aid diagnosis, although the delay between a tick bite and rash formation averages seven days and may take up to 30 days, according to the US Centers for Disease Control and Prevention. The rash also may not take on the "bull's-eye" appearance of concentric red circles.

The CDC recommends two-step serologic testing using either two immunoassays or an enzyme immunoassay or immunofluorescence assay followed by a confirmatory western blot test. However, the center notes that serology assays may deliver false negative results during the first four to six weeks after infection. PCR and culture-based testing have also been challenging because Borrelia bacteria can circulate in blood in small, inconsistent numbers.

Horreard said that the company has established in internal studies that its test can detect all of the Borrelia bacteria species that cause Lyme disease. The firm is continuing development of the test, and he hopes to have preclinical data on its performance by early 2025.

The company will follow those results with additional clinical studies to support regulatory authorizations to sell the tests in Europe and the United States, although he said that the firm has not decided which market to pursue first. The company is also early in talks with Canadian health authorities.

While the firm has yet to publish data on its Lyme disease test, Horreard noted that his company has previously tested the use of its technologies for the detection of other infections, most recently using it for the detection of Zika and chikungunya viruses in a double-blind study on serum samples from patients in Brazil. Researchers from En Carta and an international team of partners reported in 2022 in Nature Biomedical Engineering that they used isothermal amplification, toehold switch reactions, and a portable reader to detect Zika and chikungunya virus RNA in serum samples with 98.5 percent accuracy compared to PCR.

As for the Lyme disease tests, Horreard said the company has designed the test cartridge and reusable dock to look like a rapid antigen test for COVID-19 since those are already broadly familiar to the public. The company also plans to include with the kit a tick removal tool.

Once the tick is removed, the customer would use a microneedle patch to collect a sample from the bite site within five minutes, place the patch in a sample collection tube with extraction fluid, add a drop of the sample mixture to a well in the cartridge, and slide the cartridge into the dock. The dock attaches by cable to a smartphone so that the smartphone can power the heating element for the LAMP process, and the phone also is used to provide on-screen instructions during the test.

He said the test delivers results in 25-30 minutes.

Horreard said that he is not ready to disclose the estimated price of the company's Lyme disease test cartridges and dock and the company would need to make that decision by country and region.

The company will decide by test and market whether to pursue over-the-counter availability for its tests.

The firm plans to pursue US Food and Drug Administration clearance for the tests, preferably de novo marketing authorization, as well as certification as a Class C device under Europe's In Vitro Diagnostic Regulation.

The market for Lyme disease tests has been heating up as of late. In addition to the two-step serology tests that are already on the market, companies including T2 Biosystems, DiaSorin, and Qiagen have announced plans to commercialize tests that are intended to aid the early detection of Lyme disease. Kephera Diagnostics has been developing a Lyme disease ELISA with the aid of federal funding, while researchers at George Mason University recently said that they would use grants to develop a urine-based proteomic test, and five groups including T2 Bio secured funding awards this year through the LymeX Diagnostics Prize.

En Carta was founded in 2022 by Horreard, Chief Technology Officer Margot Karlikow, and strategic advisers Keith Pardee and Alexander Green. The firm's tests incorporate technologies developed at the Wyss Institute at Harvard University, the Pasteur Institute, and the Centrale Paris engineering school, and Horreard said that his three cofounders have been developing the technologies used in the tests over the past 10 years. Those technologies include the use of aptamer switches that open and close in the presence of a target sequence and that the company's scientists have used to develop fluorescent, colorimetric, and lateral flow tests.

Horreard said that Lyme disease is the proof of concept for the firm's technology. The firm also has begun development of a multiplex test for sexually transmitted infections including chlamydia and gonorrhea, and he thinks that the company will have an advantage in that market if it is able to offer privacy in testing. The company also has begun the development of a test for bacterial and viral infections that are common in pediatric patients, and it is studying the potential use of the technology for human papillomavirus screening with the identification of mutations that are connected with higher rates of cervical cancer.

"Our technology is well adapted to discriminating between different variants of a disease," he said.