New prenatal blood tests for genetic abnormalities such as Down syndrome are reshaping care for expectant mothers, but their rapid rollout has raised fears that poorly understood results could lead to confusion among patients and doctors managing high-risk pregnancies.
99.9%."Rachel Allen, a genetic counselor at the Poughkeepsie, N.Y., medical practice that caught the error, said she was puzzled by the test's failure. "Before we all get caught up in the hype, we really need to pay attention to how we can best utilize it," she said.
Verinata will soon publish a review of its field performance over its first nine months on the market, said Richard Rava, chief scientific officer for the testing firm. He expects the results to be "completely consistent" with the high detection rates shown in clinical trials, though he acknowledged the test had missed the New York case.
Dr. Rava said Verinata changed the statistics in its testing materials because "doctors were uncomfortable with anything on a report that said it was going to be 100% accurate."
Verinata's test reports include information about limitations, such as confidence intervals�a measure of the precision of an estimate�for such statistics, and fine print advises that patients receive additional testing "if a definitive diagnosis is desired."
The FDA has asked some of the companies for information about whether their products should be more closely regulated. A proposal to regulate certain "high-risk" laboratory tests, including the new prenatal screenings, has been in the works for two years and is under "administrative review," the agency said.
"We have been trying to plug some of the regulatory gaps," said Alberto Gutierrez, who leads the FDA's in vitro diagnostics group. "We want to make sure the performance of the test is good so people can make the decisions that they're going to make."
Sequenom recently released data suggesting its real-world performance tracked with trial results, based on physician feedback. "It's not the same type quality control as a controlled trial," Sequenom's Dr. Bombard said, though he expects doctors to proactively report unusual results. He said the company had sought to be conservative in its rollout by limiting the test to women with risk factors and recommending that it be administered in conjunction with genetic counseling.
Meanwhile, insurers, including UnitedHealth Group, WellPoint and Aetna, have started covering the tests, which cost between $795 for Ariosa's product and $2,700 for Sequenom's, but only for women with risk factors, such as those over 35 years old.
Physicians and test makers are split over whether the test should be distributed more widely, with some test makers beginning to sell to the broader market. There is also a hope the tests could eventually be used to gather more definitive diagnoses.
"Noninvasive prenatal [testing] as a whole has the potential to someday replace invasive procedures," said Jonathan Sheena, chief technology officer at Natera, the latest company to enter the fray. "The field has taken a giant leap forward," he said, "but we believe it is important to understand they don't replace invasive tests yet."
Write to Christopher Weaver at christopher.weaver@wsj.com
No comments:
Post a Comment