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GeneDx Launches Prenatal Exome Sequencing Test, Plans to Expand Into New Dx Areas

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NEW YORK (GenomeWeb) – Clinical genetic testing firm GeneDx of Gaithersburg, Maryland, is making plans to branch out into pharmacogenetic testing, genetic testing for disease risk assessment, and other 'omics'-types clinical tests.

The firm, which is part of BioReference Laboratories, a subsidiary of Opko Health, recently launched a prenatal exome sequencing test, which followed a six-month validation. In addition, earlier this month, GeneDx hired Benjamin Solomon as its new managing director, replacing Sherri Bale, one of GeneDx's founders. Bale is retiring but will remain a consultant to the company and continue her policy work in DC as well as her involvement with professional organizations.

Solomon, a pediatric geneticist by training, comes to GeneDx after three years at the Inova Translational Medicine Institute, where he was chief of the division of medical genomics. Prior to that, he spent eight years at the National Institutes of Health. While he plans to continue some clinical and academic work at Inova, no formal collaborations between GeneDx and Inova have been established yet.  

Bale and her colleague John Compton, both NIH scientists at the time, founded GeneDx in 2000 and jointly led the company until Compton retired several years ago. Originally, the firm focused on diagnostic testing for rare inherited disorders, and it offers between 400 and 500 genetic tests today. It was one of the first commercial genetic testing laboratories to offer exome sequencing as a diagnostic test for rare genetic diseases.

BioReference Laboratories, the third largest clinical diagnostic laboratory in the US after Laboratory Corporation of America and Quest Diagnostics, acquired GeneDx in 2006 and was itself acquired by Opko Health, a large biopharmaceutical and diagnostics company that is based in Miami, last year.

GeneDx, which has more than 400 employees in Maryland and New Jersey, works closely with BioReference both on the laboratory side and in sales and marketing, although its website does not necessarily reflect this relationship. BioReference acquired GeneDx for its genomics expertise, Bale said, and following the acquisition, the firm initially stayed largely independent, retaining its internationally well-known brand name. But as both companies continued to mature, "there has been a tremendous amount of integration and collaboration," she said. "There is a lot of sharing of expertise and ideas, a lot of integrated programs, software, and databases between the two."

Solomon now wants to take advantage of the resources afforded to GeneDx by being part of a larger organization to expand its market and its offerings in genomic medicine. "I chose Ben as the person I thought would be the best person to lead GeneDx and take it to the next level," Bale said.

Part of this strategy will be to educate clinicians and patients, who might not be aware of the benefits of genetic testing, about GeneDx's existing portfolio. "Whether it's somatic cancer profiling or someone with a family history of, let's say, a certain cardiac condition, [we want to] help make sure people get the testing they need that's going to help guide their medical treatment the best," Solomon explained.

Secondly, he said, he plans to expand genetic testing to broader patient segments "in an evidence-based way," going beyond patients with rare genetic disorders who GeneDx has traditionally served and taking advantage of new personalized medicine programs, such as the Precision Medicine Initiative. "That's a huge area and a really exciting area," Solomon said, and the firm could start with assays that are "ready for prime time," such as pharmacogenomic testing.

Also included in this category are tests predicting disease risk in apparently healthy individuals. "There are a number of conditions where there is an intervention where we don't really do the test until the disease is pretty far along and then, unfortunately, it's often too late to give the best possible therapy," he said. "So the idea is to use, again, in the best evidence-based ways, some of these tests, so we're not doing it way after it is possible to have the best interventions."

GeneDx will likely develop such tests in collaboration with academic medical centers and implement them within their healthcare systems, he added. It also has several ongoing collaborations with researchers at the nearby NIH campus.

Last year, for example, GeneDx's parent Opko signed a partnership with North Shore-LIJ Health System (since then renamed Northwell Health), under which GeneDx and Opko's GenPath are serving as Northwell's primary laboratories for genomic testing. Bale said there are other, undisclosed collaborations with healthcare systems.

Solomon also wants GeneDx to move beyond DNA-based testing and develop clinical 'omics' tests that interrogate, for example, the microbiome, measure epigenetic changes, RNA expression, proteins, or metabolites. GeneDx will develop new tests in house but might also consider licensing tests developed by others. "It depends on the specific situation," he said.

Finally, he said, GeneDx will work on new ways to deliver test results to clinicians and patients. The company is already making use of educational videos and genetic counseling services, but he wants it to take advantage of new platforms, such as mobile health apps, and to "think about ways to deliver the content even better."

In the meantime, GeneDx continues to add new genetic tests to its portfolio. A few weeks ago, the company expanded its whole-exome sequencing test to the prenatal setting, launching the XomeDxPrenatal test for ongoing pregnancies with abnormal ultrasound findings.

The launch of the test, which has a turnaround time of three to four weeks — though verbal results are usually reported within seven days — and an undisclosed price, follows a six-month validation, results from which the company plans to publish in a White Paper.

Patients can choose between two options regarding the types of results reported: while the XomeDxPrenatal Targeted test only includes pathogenic or likely pathogenic variants in genes related to the fetal phenotype, as well as variants of unknown significance if they seem of clinical significance, the XomeDxPrenatal Comprehensive test may also include variants of uncertain significance in novel candidate genes.

Patients can opt out of secondary findings in genes recommended by the American College of Medical Genetics and Genomics. Also, the exome data can be reanalyzed after the baby is born and there is better information on its phenotype.

In most cases, the test, which also requires DNA samples from both parents, would be a reflex test to a microarray-based prenatal diagnostic test, Bale said. The test uses the same sequencing pipeline as the postnatal XomeDx test, but the company prioritizes prenatal samples.

The "end-to-end" validation included about 30 cases, she said, and involved everything from sample acquisition to reporting of results. 

"We don’t really have an idea how much uptake there will be because we don't know exactly how reimbursement is going to be handled, how often patients will have to decide to pay out of pocket, what kind of institutional billing we will be doing," Bale said. "But meanwhile, we can get results for patients who may want the answers before the baby is born, who may want to use those results to make determinations about even in utero treatments."