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LDTs: FDA Gets Tough with Non-Approved PGx Testing Claims

by | Sep 16, 2019 | Essential, FDA-nir, National Lab Reporter, News-nir, Recent Headlines

From - National Intelligence Report The FDA has apparently set its enforcement sights on Laboratory Developed Tests (LDTs) that claim to predict… . . . read more

The FDA has apparently set its enforcement sights on Laboratory Developed Tests (LDTs) that claim to predict patients’ responses to medications. It began in 2018, when the FDA warned consumers and doctors that pharmacogenetics services (PGx tests) making such claims without premarket clearance or approval have not been validated. Since then, the FDA has been active in regulating labs offering PGx testing and services.

The FDA’s PGx Concerns

PGx tests look for and report genetic variants that are associated with drugs, explains Steven Tjoe, an attorney with Goodwin Procter LLP in Washington, D.C. and former regulatory counsel in FDA’s Center for Devices and Radiological Health. Genetic variants occur throughout the population. Some are benign, some may be known to cause specific diseases, and others may be associated with variable response to specific medications. These variants occur in genes that, for example, code for drug-metabolizing enzymes or drug targets.

Thus, test results might suggest that a doctor or a patient should adjust the dosage of a medication or choose a different drug altogether. But, Tjoe explains, the FDA’s position is that there may be insufficient evidence to support claims for how a patient will respond to specific medications for PGx tests the FDA hasn’t reviewed.

The November Warning Shot

On Nov. 1, 2018, the FDA issued a Safety Communication to alert patients and physicians

that genetic lab tests which purport to predict a patient’s response to specific medications have not been reviewed by the FDA and may not be supported by sufficient scientific or clinical evidence. The FDA cites genetic tests that claim to be capable of predicting whether certain medications used to treat depression may be less effective or have an increased chance of side effects. The relationship between variations and the effectiveness of antidepressant medication has never been established, the Safety Communication states. So, changing drug treatment based on the results from such tests could result in inappropriate and potentially harmful treatment decisions.

The Follow-Up Enforcement

In the Safety Communication, the FDA also says it’s looking into certain developers that may be inappropriately selling genetic tests for the unapproved uses and will take compliance actions when appropriate. Since the Safety Communication was published, the agency has, in fact, directed its attention to several firms over the marketing of predictive medication response PGx tests where the relationship between genetic (DNA) variations and the medication’s effects hasn’t been established.

In April, the FDA issued a warning letter to Inova Genomics Laboratory for marketing genetic tests that claim to predict patients’ responses to specific medications without FDA clearance or approval See Lab Industry Report (LIR), April 29, 2019. In response to that letter, Inova has reportedly stopped offering its PGx tests.  Inova is far from alone, says Tjoe, with other labs similarly being contacted by FDA regarding their PGx test offerings.

Impact on Labs

Tjoe notes that labs offering PGx tests, including those that haven’t gotten an FDA warning letter, are currently trying to figure out what to do. Many labs have reportedly stopped reporting drug information and no longer mention any drugs on their websites and marketing materials. Tjoe advises clinical labs that are reviewing their LDT marketing materials, test menus, test reports and other labeling to closely monitor the FDA’s actions while being cognizant of the agency’s past compliance activities and concerns in initiating this latest round of enforcement action.


Recognize that the FDA’s current enforcement activities against clinical labs offering PGx tests as LDTs are part of the larger discussion among the agency, Congress, regulators and labs about whether and how to regulate LDTs. Labs need to pay close attention to these conversations, not only for clues as to FDA’s enforcement priorities but also to see what the FDA, Congress and other regulators will actually do about LDTs regulation.

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