The first liquid biopsy used to detect gene mutations that are associated with non–small-cell lung cancer (NSCLC) was approved by the US Food and Drug Administration (FDA). The cobas EGFR Mutation Test v2 (Roche Molecular Systems), a blood-based companion diagnostic for erlotinib (Tarceva), is indicated as an initial test to detect EGFR gene mutations in patients with NSCLC.
Lung cancer is the second most common cancer in the United States and is the leading cause of cancer-related death. According to the National Cancer Institute, an estimated 158,080 Americans will die from the disease this year.
According to guidelines by the National Comprehensive Cancer Network, NSCLC accounts for 85% of all lung cancer cases in the United States, of which 10% to 50% are associated with EGFR gene mutations.
In patients with NSCLC, tumor DNA is released into the bloodstream. A liquid biopsy uses the patient’s blood plasma to isolate these tumor cells and to detect specific mutations.
By detecting specific NSCLC EGFR mutations (exon 19 deletion or exon 21 [L858R] substitution mutations), clinicians can use the liquid biopsy to determine which patients will benefit from treatment with erlotinib, which was approved by the FDA in 2013 as a first-line treatment for metastatic NSCLC in patients whose tumors have EGFR mutations.
A blood-based liquid biopsy is less invasive than a traditional tissue biopsy and can be repeated, whereas, in certain cases, a tissue biopsy cannot.
“Approvals of liquid biopsy tests make it possible to deliver highly individualized healthcare for patients,” said Alberto Gutierrez, PhD, Director of the FDA’s Office of In Vitro Diagnostics and Radiological Health. “Liquid biopsies also have the potential to allow physicians to identify patients whose tumors have specific mutations in the least invasive way possible.”
According to research presented at the 2015 European Lung Cancer Conference, EGFR genetic testing is not done in 25% of patients with NSCLC, despite guidelines from the International Association for the Study of Lung Cancer that recommend all patients diagnosed with advanced NSCLC (except those with squamous-cell carcinoma) have EGFR genetic testing.
“The advent of liquid diagnostic platforms in non–small cell lung cancer is truly a game changer in the diagnostic workup of advanced stage patients. The ability to both isolate and genetically interrogate tumor DNA from a simple, minimally invasive test that can subsequently inform treatment decisions is a win for both physician and patient,” said Benjamin Levy, MD, Medical Director of Thoracic Medical Oncology, Mount Sinai Health Systems, New York, in a statement. “These platforms have the potential to expedite care and potentially circumvent an otherwise cumbersome process of procuring tissue (biopsy) often fraught with complications and complexity.”
The approval of the cobas EGFR Mutation Test v2 was based on the accuracy of blood samples from patients who were enrolled in a clinical study and had EGFR mutations confirmed with tumor biopsies.
