In a prelude to overhauling its regulatory oversight of genetic diagnostic testing, the U.S. Food and Drug Administration will convene a public meeting next week to gather input from test makers and others.
The event reflects a turning point in genetic testing, a cornerstone of personalized medicine. Once mainly the domain of rare diseases, scientists have discovered a growing number of genetic variations linked to both the risk of more common disease and patients’ response to drugs. The number of genetic diagnostic tests has expanded rapidly, and tests have become increasingly complex, making it more challenging to interpret and act on the results.
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“We don’t think physicians are going to be able to interpret the results; they are relying on the labs that make them,” says Alberto Gutierrez, director of the Office of In Vitro Diagnostic Device Evaluation and Safety at the FDA. “So we think a third party should assess these devices.”
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The early generation of genetic tests was relatively simple, testing for a single cancer-linked gene, for example. The possible treatment decisions or other responses were well-defined. But in the last few years, these tests have incorporated more genes and tackled more complex and common diseases. “The scope of these tests and how they can be used is growing rapidly,” says Alexis Borisy, chief executive officer of Foundation Medicine, a startup based in Cambridge, MA, that is developing genetic tests to predict the most effective drugs for cancer patients. More than 2,000 genetic tests are now available through clinical laboratories.
However, tests developed and performed in a single laboratory today face little federal regulation other than that they be performed in a certified laboratory. (Some states, such as New York and California, have stricter laws, such as requiring that a physician order clinical tests.) For these “laboratory developed” tests, physicians collect a sample from patients and then send them to a specific lab. So-called test kits, which are sold to hospitals and other labs so that they can perform the tests themselves, are subject more extensive regulation.
The FDA has made several moves toward more extensive regulation in recent years, but the regulatory issue came to a head in May when Pathway Genomics announced plans to sell its genetic tests in drugstores. Those plans were halted when the agency sent Pathway and other genetics testing companies a letter questioning whether the tests could be sold without the agency’s approval. A month later, the agency issued a statement describing its intent to rethink its approach to all laboratory-developed tests.
“These tests, which are becoming more complex and high risk, are playing an increasingly important role in clinical decision-making. As a result, LDTs [laboratory developed tests] that have not been properly validated put patients at risk, such as for missed diagnosis, wrong diagnosis, and failure to receive appropriate treatment,” the agency explained in the statement. Because of the lack of existing regulation, little data exists on error rates or misinterpretation of the tests.
“The primary concern was once just analytic validity; does it accurately measure what it says it does?” says Daniel Vorhaus, an attorney at Robinson, Bradshaw & Hinson, in Charlotte, NC, and editor of the firm’s Genomics and Life Sciences blog. “That’s still very important, but now there are other issues as well. How are people using the information? Is the interpretation of information accurate? What do I do with the information?” For example, if a test predicts that someone is at greater risk for diabetes, a physician could suggest diet and exercise or a more aggressive approach involving drugs.
The agency says it plans to take a risk-based approach, meaning that tests linked to major medical decisions will be more tightly regulated than those that might predict a minor increase in risk for disease.
