New Down syndrome prenatal test not FDA-approved

The newest prenatal test for Down syndrome–non-invasive prenatal screening–is not FDA-approved. It’s not because it doesn’t have to be. But that may change.

On September 9, 2014, the House Energy & Commerce Committee’s Subcommittee on Health held a hearing concerning the US Food & Drug Administration’s (FDA) proposed plan for regulating what are called “Laboratory Developed Tests” or “LDTs.” Turna Ray, editor of GenomeWeb’s Pharmacogenomics Reporter, provided a good report of the proceedings.

LDTs report inaccurate results

Historically, the FDA has not regulated LDTs, leaving oversight to the Centers for Medicare & Medicaid Services through the standards set for Clinical Laboratory Improvement Amendments (CLIA). Jeff Shuren testified on behalf of the FDA, and made the point (as reported by Ray) that :

CLIA looks at the analytical validity of tests (whether the test is gauging the marker it’s supposed to), but it doesn’t ensure clinical validity (whether the test can predict patients’ clinical outcome).

Shuren went on to provide examples of where LDTs had inaccurate results.

These concerns had already been made to Congress in July. Ray further reported how the FDA Commissioner Margaret Hamburg said in a report that leaving LDTs subject only to CLIA standards, and not the heightened review of the FDA, “has resulted in patients getting erroneous results or unnecessary testing.”

NIPS labs are LDTs

All of the manufacturers of non-invasive prenatal screening (NIPS)–Sequenom, Illumina/Verinata, Natera, and Ariosa–fall under the LDT exception. They must comply with CLIA, but that does not mean their tests results can predict a patient’s outcome. One needs only to review the comments at this post to see the confusion caused by how NIPS labs report their results to patients.

Christopher Newton-Chech testified at the hearing on behalf of the American Heart Association. He likened LDTs to the snake oil salesmen of the 1800’s:

[The American public] would not support rolling back to a 19th century Wild West, where snake oil is indistinguishable from safe and effective therapies … they would not accept continuing unregulated LDTs in the 21st century.

Snake oil or Holy Grail?

The unregulated nature of the NIPS labs has led the International Society of Prenatal Diagnosis to express “serious concern” about the validity and clinical utility of NIPS testing. An editorial featured in the New England Journal of Medicine called for caution in embracing the newest blood test for Down syndrome because so little is shared by the labs about the actual performance of their tests.

NIPS, however, was not the focus of the hearing on whether the FDA will regulate LDTs. If the FDA begins regulating LDTs, though, it’s only a matter of time before NIPS labs will fall under that review.

Given that the newest test for Down syndrome has been hailed for its high level of accuracy, it will be worth following what reaction the NIPS labs have: whether they welcome receiving the higher scrutiny of their  testing from FDA oversight, or if they resist it to continue to withhold the full information about the accuracy of their tests.