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Diassess Progresses Towards Instrument-Free Molecular STD Testing


NEW YORK (GenomeWeb) – Diagnostics developer Diassess has been awarded a Phase II Small Business Innovation Research grant from the National Institutes of Health to support further development of a rapid, instrument-free gonorrhea test.

The funding, which totals $716,689 in the first year of a two-year grant, follows $707,926 in year-one Phase II SBIR funds awarded in June of last year for chlamydia assay development.

Eventually the Emeryville, California-based firm plans to have a combined chlamydia and gonorrhea test, Diassess co-founder Debkishore Mitra said in an interview.

Diassess is aiming squarely for the point-of-care molecular space with its handheld assays. A major differentiating factor for the firm is that other currently available tests require an instrument to run them while Diassess' tests are completely instrument free.

"What we are trying to bring into the market is something which has a lateral flow [immunoassay] footprint but can actually run a molecular test with high sensitivity and specificity," Mitra said.

Overall test time is 35 minutes, but Mitra said he expects that to come down with further test optimization. The firm has simplified sample extraction, sample preparation, and detection such that it does not require any extraneous equipment to run a test, he said. The extraction method is a rapid chemical preparation scheme, while the detection method is colorimetric.

Between these two steps, the amplification is rather agnostic as to isothermal method, Mitra said. The firm has so far tested methods such as loop-mediated isothermal amplification (LAMP), strand displacement amplification (SDA), and recombinase polymerase amplification (RPA), although he declined to say which method it now uses. "How the assay detects the amplification is what we are trying to make easy, without being too dependent on what the assay itself should be," he said.

The US Centers for Disease Control and Prevention and US Preventative Services Task Force provided new guidelines in 2014 that strongly encouraged the use of commercially available nucleic acid amplification tests for chlamydia and gonorrhea screening and testing. At that time, laboratorians noted that a US Food and Drug Administration-validated, CLIA-waived, rapid, point-of-care chlamydia and gonorrhea test would be a "game changer" for public health.

Mitra highlighted that CLIA waiver effectively shows that a test is easy to use. "That is something that was key when we started designing our product, to make sure there are as minimal number of steps as possible to process the sample, and also that the readout is intuitive and that there is little chance for anyone to miss any steps," he said.

Competing technologies in the crowded point-of-care molecular space might include systems like the Alere i, the Roche Liat, the proposed Cepheid Omni, Meridian Bioscience's Illumigene, or the Quidel Solana.

A number of these are already CLIA-waived for at least one infectious disease test, but all of them are also instrument-based systems. Mitra noted that the cost of purchasing a platform on which to run tests, the reimbursement rate for a platform, as well as long-term costs of instrument maintenance could be an obstacle for some users in the CLIA-waived market.

The Diassess tests, on the other hand, would enable physicians and clinics to "basically buy the product without the need for any extra equipment that needs to be purchased, or for training or calibration, " Mitra said. "It's going to be an interesting launch to see how we match up with these competitors."

Both the gonorrhea and chlamydia tests are being developed in collaboration with well-known researchers. Deborah Dean, head of the Chlamydia Research Laboratory at the Children's Hospital of Oakland Research Institute, is a PI on the gonorrhea grant and Diassess has a long collaboration history with her, including prior Phase I and II grants, Mitra said. Dean also contributed key IP to the sample preparation method, and provided the firm with clinical guidance and samples to test prototypes.

Charlotte Gaydos, a professor of infectious diseases at Johns Hopkins University, is serving as a co-investigator on the gonorrhea grant and is also an expert in sexually transmitted disease diagnostics. "She has been a very key guiding light in terms of explaining what kind of metrics and what kind of main features should be focused on," Mitra said, adding that Gaydos will also be providing clinical samples to evaluate the performance of the test.

Around 2.8 million people are infected annually with chlamydia in the US, while only about 800,000 gonorrhea infections are reported each year. However, gonorrhea rates have been increasing and the bacteria is also developing drug resistance such that there is "the very real threat of untreatable gonorrhea on the horizon," according to Robert Kirkcaldy, a medical epidemiologist in CDC’s Division of STD Prevention.

Mitra said that the Diassess tests can be multiplexed for up to 10 targets, and the firm intends to stay in touch with clinical research on new potential targets. "If the [STD] community at large is able to find biomarkers that are reliable for drug resistance, I think the Diassess platform will not be far behind in making sure that we provide the best care to the patient," he said.

The gonorrhea SBIR project is set to conclude at the end of 2018, at which point Diassess expects to have a fully-integrated system with high sensitivity and specificity for further evaluation, Mitra said. The firm will then be submitting it to the FDA for regulatory clearance, likely via a 510(k) mechanism. Following this, Diassess will submit the test for CLIA waiver, and its business development team and network of experts is currently developing strategies for marketing and distributing the test once it is launched.