FoundationOne Liquid CDx “Liquid Biopsy” Blood Test Gets Expanded FDA Approval

Roseate spoonbill in southwest Florida; photo by Shutterstock

If you are considering genetic testing to identify whether a potential therapy might be useful against your prostate cancer, this article may be helpful to you. This test can help identify genetic changes such as BRCA1, BRCA2 and ATM mutations in which case a corresponding targeted drug, such as olaparib (Lynparza), may be useful.

The Food and Drug Administration (FDA) has expanded the approved uses for a blood test, known as a liquid biopsy, that can help doctors pick the best treatments for some people with cancer. The test identifies cancer-related genetic changes in DNA from tumor cells that have been released into the blood.

The test, called FoundationOne Liquid CDx, was approved by FDA earlier this year to identify patients with lung and prostate cancer who can receive specific targeted drugs. When the test is used in this way, it’s known as a companion diagnostic.

Under the expanded approvals, announced by FDA in late October and early November, the use of the test as a companion diagnostic has been broadened to people with other cancers and other drugs not covered by the original approval. (See table.)

FoundationOne Liquid CDx and another cancer liquid biopsy test, Guardant360 CDx, were initially approved by FDA earlier in 2020. Both approvals covered use of the tests as companion diagnostics for several targeted therapies. The initial approvals also covered the use of the tests for general tumor profiling, meaning they can be used to identify a large number of specific cancer-related genetic changes, any of which may influence patients’ treatment choices or make them eligible to participate in certain clinical trials.

According to FDA, the expanded approval of FoundationOne Liquid CDx was based on analyses of the test’s use on blood samples from patients participating in clinical trials evaluating the targeted drugs.

In instances where the blood test does not identify the specific genetic change that means a patient can receive a corresponding targeted therapy, the agency advised that the patient’s tumor tissue should be analyzed “to determine if the specific mutations and alterations are present.”

Most of the above was published by the National Cancer Institute (NCI) Current Contents Blog on November 30th, 2020.

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