The Food and Drug Administration has approved the first companion diagnostic test to detect epidermal growth factor receptor gene mutations.
The cobas epidermal growth factor receptor (EGFR) mutation test will be used to determine whether non–small cell lung cancer (NSCLC) patients with the mutation are eligible for treatment with erlotinib (Tarceva). That already-marketed small-molecule tyrosine kinase inhibitor received expanded approval as a first-line drug in metastatic NSCLC.
"Companion diagnostics play an important role in determining which therapies are the safest and most effective for a particular patient," said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, in a statement.
According to test maker Roche Molecular Systems, the cobas EGFR Mutation Test is "a real-time PCR [polymerase chain reaction] test for the qualitative detection and identification of mutations in exons 18, 19, 20 and 21 of the epidermal growth factor receptor (EGFR) gene in DNA derived from FFPET [formalin-fixed paraffin-embedded] human NSCLC tumor tissue." The test can be conducted in 8 hours.
About 85% of the 228,000 cases of lung cancer in the U.S. are NSCLCs, according to the National Cancer Institute.
Both the American Society of Clinical Oncology (ASCO) and the National Comprehensive Cancer Network (NCCN) have recommended EGFR testing for patients considering tyrosine kinase inhibitors as first-line therapy in metastatic or recurring NSCLC.
ASCO issued a provisional clinical opinion on the subject in May 2011, and the NCCN updated clinical management guidelines earlier that year to include a category 1 recommendation that EGFR testing should be undertaken after histologic diagnosis of adenocarcinoma, large cell carcinoma, or undifferentiated carcinoma.
Both groups based their endorsements on studies demonstrating that mutations in two regions of the EGFR gene appear to predict tumor response to chemotherapy in general and to tyrosine kinase inhibitors specifically.
On average, NSCLC patients who had the two EGFR mutations detected by the cobas EGFR Mutation Test and who took erlotinib lived 10.4 months before their disease progressed, compared with 5.4 months for those who received a standard two-drug chemotherapy regimen.
Erlotinib was first approved in November 2004 for treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen. It has received two other approvals before the current one, including for maintenance treatment of patients with locally advanced or metastatic NSCLC whose disease has not progressed after four cycles of platinum-based first-line chemotherapy.
The drug is comarketed by Genentech, a member of the Roche Group and OSI Pharmaceuticals.
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