Cellscape Hunts for Fetal Cells in Mom, Pushing Diagnostic Frontier

Xconomy San Francisco — 

[Correction: 3:15 pm PT] You can learn a lot about a potential human being if you can get your hands on a few red blood cells from a developing fetus.

The thing is, these cells are fragile and hard to obtain. More than 50 companies have tried and failed to create a reliable, noninvasive way to get these precious cells, and extract all kinds of genetic information from them for diagnostic purposes.

Newark, CA-based Cellscape is betting it is zeroing in on a way to do it.

Cellscape has raised a little less than $20 million since it was founded five years ago by Karen Drexler, Bhairavi Parikh, and James Stone. It isn’t yet ready to take its proprietary test to the market, but Cellscape made a preliminary move in that direction this summer by hiring an experienced commercial diagnostic CEO in Ted Snelgrove, formerly of Crescendo Bioscience.

Already, a group of four companies—Sequenom, Illumina’s Verinata Health unit, Ariosa Diagnostics, and Natera—have made progress in the past year building a new market for noninvasive prenatal tests, which extract information from small amounts of fetal DNA circulating in a mother’s blood. But those tests aren’t perfect, as they are limited mainly to looking for chromosomal abnormalities like Down syndrome, and sometimes yield inconclusive or false positive results. Cellscape seeks to raise the bar by getting a richer source of information than trace DNA from the mom’s blood—whole fetal cells that still have an intact nucleus. Those are the type of cells that physicians today can obtain through procedures known as CVS or amniocentesis, but those tests are invasive, come with a risk of miscarriage, and generally aren’t done unless the physician has a strong reason to believe something’s wrong.

The ultimate prize for Cellscape would be to come up with a test that’s reliable enough to become a standard first-trimester diagnostic tool like ultrasound, in a country where 4 million children are born every year. If the company can nail down a reliable diagnostic test over the next couple years, it could make it possible for doctors and patients to discover genetic abnormalities in fetuses that can’t be spotted through today’s noninvasive means.

“There’s a strong emphasis in understanding the genetics at the front end of life, and it’s a harbinger of change that’s coming,” says Cellscape CEO Ted Snelgrove. “The power of the information is strong.”

Gautam Kollu, a former vice president of marketing at Natera, a non-invasive prenatal testing company currently on the U.S. market, said he was impressed by Cellscape’s addition of Snelgrove. But he says the company still has a lot to prove. “Very interesting technology indeed, if it turns out to be real. There are a lot of hurdles to still overcome,” he said.

The technical hurdles were immediately apparent to Cellscape’s founding team in 2008, but they also saw a lot of lessons in what didn’t work, and a challenge that didn’t seem impossible. Technology was getting sensitive enough to detect circulating tumor cells (CTCs) in blood, even when there’s only one present out of 1 billion cells. So they reasoned that similar platforms could be used to find the fetal red blood cells floating around in a mom’s bloodstream, which are just as rare. “We spent the first year studying what other people had done, and had a lot of knowledge of what not to do,” says Drexler, the company’s executive chair.

Karen Drexler, co-founder and executive chair of Cellscape

Karen Drexler, co-founder and executive chair of Cellscape

Cellscape, which also went by other names like Saryna Medical and Abraza Medical in its early days, raised its first $800,000 in May 2009 from XSeed Capital Management and angel investors. It was a small miracle, given those were some of the darker days of the recession, and Cellscape hadn’t even begun developing a technology. “We had an approach in mind,” Drexler says.

There are several reasons why it’s hard to get fetal cells in a noninvasive procedure.

For starters, they’re rare. That means if you want to make sure to get enough cells to analyze, you have to draw a lot of blood from the patient.

They’re also fragile, and likely to die when handled by rough instruments, unlike tumor cells, which are hardy by the standards of ordinary cells. This is where a lot of other companies stumbled, Drexler says, noting that procedures which work for capturing circulating tumor cells—such as magnetic cell separators—are too harsh for fetal cells.

Plus, there’s a narrow window of opportunity to capture the right kind of cells. Cellscape has focused on fetal red blood cells with intact nuclei, because there’s no way those cells can live on in the mom’s bloodstream from a previous pregnancy, and therefore set off false signals about the current fetus. The trouble with nucleated fetal red blood cells, though, is that they live in a different environment in the womb, with different oxygen and acidity levels, and they are thought to live only a few days when they enter the mom’s bloodstream, Drexler says.

Given those basic parameters, here’s what Cellscape does: It starts … Next Page »

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3 responses to “Cellscape Hunts for Fetal Cells in Mom, Pushing Diagnostic Frontier”

  1. Daen de Leon says:

    I’d just like to give some more information regarding one comment you made regarding NIPT results (“those tests aren’t perfect, as they are limited mainly to looking for chromosomal abnormalities like Down syndrome, and sometimes yield inconclusive or false positive results”). Natera has conducted clinical validation studies of its Panorama test which show sensitivity of 99% for T13, T18, and T21, and 92% for monosomy X; and specificity of 100% with no false positives for T13, T18, T21, and monosomy X.


  2. Harmony Jones says:

    Daen de Leon: Natera has an incredibly small sample size they studied. This is not so impressive in an unblinded study (aka open book test).