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Inex Innovations Exchange Developing Fetal Cell-Based NIPT to Expand Test Portfolio


NEW YORK (GenomeWeb) – Reproductive health molecular diagnostics firm Inex Innovations Exchange of Singapore is betting on fetal cell-based noninvasive prenatal testing to expand its business in the future.

Last month, the company, a 2006 spinout from the National University of Singapore, said it had exclusively licensed technology for isolating circulating fetal cells from maternal blood and analyzing their DNA from the Agency for Science, Technology and Research (A*STAR), which provides funding from the government of Singapore for research and development in several technology areas.

According to a company spokesperson, Inex licensed know-how around sample processing and device manufacturing from A*STAR, not patents, though it has several patents pending around related technology, for example a method for identifying, isolating, and culturing fetal erythroblasts. Inex said the deal with A*STAR includes fetal cell isolation technology, as well as the design and development of semi-automated instruments for noninvasive prenatal diagnostics.

Chia-Pin Chang, vice president of R&D at Inex, said the company is currently developing an assay for fetal cell-based NIPT, which it hopes to be able to evaluate in a multicenter study starting in late 2018 or early 2019.

Several other companies and academic groups have also been working on ways to isolate fetal cells from maternal blood for DNA analysis, among them FetoLumina Technologies, Baylor College of Medicine, and Arcedi Biotech. The promise of the approach is to deliver diagnostic information from pure fetal DNA in a noninvasive manner.

Chang said he believes that fetal cell-based prenatal DNA testing could eventually replace both cell-free NIPT and invasive diagnostic prenatal DNA testing. "Potentially, you can look at more than 6,000 fetal genetic diseases," he said. However, over the next five to 10 years, there will likely still be a market for cell-free NIPT, especially as those tests keep getting less expensive over time, he added.

Inex is already active in noninvasive prenatal testing: in 2014, the company launched iGene, a cell-free DNA-based NIPT that screens for several trisomies, sex chromosomal aneuploidies, and a number of microdeletion syndromes and has a turnaround time of seven to 10 days. The test, which relies on genome-wide sequencing and read count analysis, is performed by iGene Laboratory, a wholly owned subsidiary of Inex that is located in Singapore. According to its website, iGene Laboratory uses Thermo Fisher Scientific's Ion Proton platform to run the assay. The iGene test uses an algorithm from BGI of China, acquired through a technology transfer, that BGI originally developed for its NIFTY test.

In addition, Inex sells OvaCis, a rapid in vitro diagnostic point-of-care kit to distinguish between benign and malignant epithelial ovarian cysts. OvaCis, launched in 2014 and the firm's first product, was developed by Inex and researchers at the National University of Singapore and is patent-protected. Last year, OvaCis became CE-marked for in vitro diagnostic use. It is a colorimetric assay that tests ovarian cyst fluid for a protein biomarker and takes five minutes to perform, providing a yes-or-no answer. It is designed to be used during surgery to make surgical decisions and has a sensitivity of more than 98 percent and specificity of more than 92 percent, according to the company.

The development of the new fetal-cell based test goes back to a collaboration that Inex and A*STAR's Institute of Microelectronics (IME) announced in 2015. At the time, the partners said they would use IME's rare cell isolation technology, which relies on a microfluidic chip that contains a microfabricated filter membrane to enrich fetal cells from maternal blood. The filter removes more than 99.9 percent of non-target cells from a blood sample and recovers about 85 percent of fetal cells. According to Inex, the approach is less likely to lose fetal cells than other methods that use centrifugation or cell lysis.

Chang declined to provide additional details about the rare cell isolation technology but said that the collaborators have altered the microfluidic chip design and are preparing a manuscript that describes the method, which they hope to publish within a year. Unlike other approaches, he said, Inex's does not positively enrich fetal cells but rather depletes non-target cells. After that, it picks fetal cells for analysis. Inex said the method uses several antibodies to stain trophoblasts in maternal blood.

Developing the assay involves the isolation of fetal cells and molecular profiling of their DNA, he said, and the company has been focusing on both aspects. While the researchers are now able to get several fetal cells out of every sample tested, some can be profiled more easily than others, depending on how damaged they are. "Some of the single cells behave better than others," he said. "That's something we're trying to overcome, [establishing] how many cells need to be isolated in order to perform a good analysis, whether a single cell or three cells are good enough, or whether we need 10 cells to make a good diagnosis."

The company is currently working on a research-use-only version of the fetal cell-based DNA test that it hopes to employ in a multicenter clinical study in late 2018 or early 2019. For that, it will be looking for overseas collaborators because Singapore is too small to obtain sufficient samples from pregnant women, Chang said, and because the researchers want to test the technology in different populations. The goal is to test not only for trisomies but also for microdeletions and single-gene mutations. "Somewhere in 2021, we should be able to conclude the study. If the results are good, which we believe they will be, we have plans to manufacture our devices and reagents, and then, probably by 2021, we will have an RUO version ready for people to adopt," he said.