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FDA Tells Patients, Docs to Take Caution When Using Unapproved PGx Tests to Make Treatment Decisions

NEW YORK (GenomeWeb) – The US Food and Drug Administration today cautioned patients and healthcare providers against changing treatments based on results from pharmacogenetic tests with unproven indications that the agency hasn't approved for marketing.

The FDA further indicated it is looking into companies selling PGx testing for unapproved uses and may take compliance action against these firms.

"The FDA is alerting patients and healthcare providers that claims for many genetic tests to predict a patient's response to specific medications have not been reviewed by the FDA, and may not have the scientific or clinical evidence to support this use for most medications," the agency said in an alert. "Changing drug treatment based on the results from such a genetic test could lead to inappropriate treatment decisions and potentially serious health consequences for the patient."

The agency's alert for physicians and patients came hours after granting consumer genomics firm 23andMe marketing authorization for several pharmacogenetic tests.

The FDA has previously stated that tests that claim to predict patients' ability to respond to specific drugs or their risks for adverse events to treatments confer the highest risk to public health and have to be reviewed by the agency before they can be marketed to patients, either directly or through a doctor.

Regardless, in the past few years, a spate of new consumer-facing genetic testing companies have begun selling pharmacogenetic testing products without the agency's approval, claiming they are meeting regulations by performing testing in CLIA-certified labs. These companies have further asserted that they're not really direct-to-consumer genetic testing companies in the way 23andMe is because they're using third-party physician networks to order the tests.

One company that recently introduced PGx testing to its consumer-facing, online testing service is Color Genomics. The company performs testing in a CLIA-certified lab and allows patients' own doctors to order testing, or have a doctor from a third-party network order it. The company provides genetic counseling with clinically significant results and connects patients to pharmacists with expertise in pharmacogenetics for the cost of the service. Color didn't reply to a request for comment ahead of deadline.

Still, other companies are analyzing raw genetic data generated by companies like 23andMe and using software to pull out PGx variants from that data and report them to patients. These companies, because they're not operating a wet lab, claim they aren't subject to CLIA requirements as well.

The FDA said in its alert that it is aware of all these practices companies are using to skirt the agency's oversight. "The FDA is looking into certain developers that may be inappropriately selling genetic tests for the unapproved uses noted above, and will take compliance actions when appropriate," the agency said in the alert. "We will continue to monitor reports of adverse events associated with this issue and will keep the public informed if significant new information becomes available."

In particular, the agency called out companies offering non-FDA approved or cleared PGx tests that claim to help physicians identify which antidepressants patients will best respond to or experience side effects from. "However, the relationship between DNA variations and the effectiveness of antidepressant medication has never been established," the agency said.

The agency acknowledged that doctors already may be making treatment or dosing decisions on antidepressants based on PGx tests it hasn't approved or cleared, but cautioned that doing so "may put the patient at risk for potentially serious health consequences."

Myriad Genetics markets the GeneSight pharmacogenomic test for patients with moderate to severe depression. The test, performed in a CLIA-certified lab, isn't approved by the FDA, though the company has conducted a number of studies to demonstrate the ability of its test to guide patients to appropriate depression medications. A spokesperson for the company highlighted a recently published large, prospective study that showed that using GeneSight to guide treatments statistically significantly improved patients' ability to achieve remission compared to treatment as usual using trial and error.

In response to a request for comment on the FDA's alert, Ron Rogers, Myriad's executive VP of corporate communications, instead made several points about the agency's recent authorization of 23andMe's PGx test. First, he noted that the agency's authorization of 23andMe's PGx test is unlikley to impact its business because the FDA also stipulated a number of caveats, notably that 23andMe's test doesn't provide medical advice and that the results should only be used after confirmation with a clinical pharmacogenetic test. Rogers further differentiated Myriad's test from 23andMe's test, which detects individual PGx SNPs, noting that the former uses a multigenic combinatorial testing approach.

The FDA alerted doctors and patients that when there is evidence to support a correlation between a genetic variant and levels of a drug in the body, the agency recognizes this by updating drug labeling and by approving or clearing genetic tests.

"The FDA-authorized labels for these medical products may provide general information on how DNA variations may impact the levels of a medication in a person's body, or they may describe how genetic information can be used in determining therapeutic treatment, depending on the available evidence," the agency said, directing patients and providers to look for this information in the warnings, indications and usage, dosage and administration, or use in specific population sections of drug labeling.

The agency informed patients that most PGx tests that claim to predict response to certain drugs lack evidence supporting those claims. As a result, they should not change or stop taking medications based on the results of a genetic test without discussing the test results with their own doctor.

The agency advised doctors and labs to reference the FDA-approved labeling for a drug for information on the link between DNA variations and efficacy, before providing any treatment recommendations based on the results of a genetic test.

Some genetic test labels may include information about how genetic variants impact drug levels, but don't say how that information should inform treatment. "These labels are intended to be informational, but do not indicate that there is sufficient evidence to support making treatment decisions based on the information provided by the genetic test," the agency said.

To genetic testing companies, the agency's advice was that they should make sure their claims for a PGx test conform to information in FDA-approved drug labeling. "Assure your test report and any labeling support an intended use that is consistent with the FDA-approved use of the medication," the agency said, adding that companies should contact teh agency with questions about the alert.