From the News page, some significant developments concerning cell free DNA, with commentary by Anchorman Ron Burgundy:
Court invalidates Sequenom’s Prenatal DNA Patent
An appellate court has upheld a decision granting summary judgment to Ariosa in defending itself against claims fo infringement by Sequenom of Sequenom’s prenatal DNA patent. Based on other Supreme Court jurisprudence, because Sequenom’s test is based on a phenomena of nature, it is not patentable. More on the original decision at this post.
Ariosa licenses technology to European labs
Coincidentally, 24 hours prior to being cleared of claims of infringement, Ariosa’s Harmony test was licensed to European labs after receiving a regulatory certification. Having already tested 500,000 women globally, Ken Song, Ariosa’s CEO, said the licensed labs, “represent a significant step in reaching our goal to offer the broadest access to the world’s leading and most validated NIPT to pregnant women worldwide.
cell free DNA testing expected to have greatest market growth of prenatal testing
Surely the goal to offer the broadest access to Ariosa’s Harmony, and other cell free DNA tests, is completely unrelated to the market for prenatal testing being valued at $1.2 Billion in 2012 with expected growth to $8.37 Billion by 2019, with cell free DNA testing expected to have the greatest growth.
99% accuracy = 81% (or 76%)
A recent study on the relative accuracy of cell free DNA testing reports that while it detects pregnancies actually carrying a child with Down syndrome 99% of the time, when false positives are factored in, it has a positive predictive value of 81% for patients who had conventional screening and 76% in low-risk populations.
The New England Journal of Medicine noted that the reported accuracy rates of 99% for detecting pregnancies actually carrying a child with Down syndrome occurred in sample sizes with an unnaturally high incidence rate for Down syndrome. The line that a test, when conducted in a population not reflective of the actual population, has a 99% accuracy rate reminds me of the line: “They’ve done studies you know: 60% of the time, it works every time.” Even Ron Burgundy knows that doesn’t make sense.
Leading cell free DNA researcher raises concerns over informed consent
So says Diana Bianchi, lead researcher for the cell free DNA test verifi, in a commentary in Nature.
Bianchi raises caution over mothers receiving unexpected incidental findings from their tests, like the recent headlines reporting these tests detecting cancers in the mother:
A healthy pregnant woman has a blood test to rule out the possibility that her baby has certain abnormalities, such as Down’s syndrome. One week later, a genetic counsellor calls her and recommends a follow-up test such as amniocentesis. When the counsellor calls again, she says that the baby is healthy but that the mother needs to be screened for cancer.
With these incidental findings comes complicated counseling, which is not adequately addressed by current informed consent forms, says Bianchi:
I reviewed the consent forms used by five major US commercial providers of non-invasive prenatal blood tests. In two of them the physician, not the mother, signs the form stating that the mother has been counselled. In two of the other three, the mother signs the form, but the form either does not mention incidental findings or it explicitly states that the laboratory will not report them. Only one notes that, “in rare circumstances, genetic testing may reveal sensitive information about your own health”.
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