On 1 June, 2016 the US Food and Drug Administration (FDA) approved the cobas EGFR Mutation Test v2, a blood-based companion diagnostic for the cancer drug erlotinib (Tarceva). This is the first FDA-approved, blood-based genetic test that can detect epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer (NSCLC) patients. Such mutations are present in approximately 10-20% of NSCLC.
NSCLC tumours may shed tumour DNA into a patient’s blood, making it possible to detect specific mutations in blood samples. Testing for tumour DNA using a blood sample is also called a liquid biopsy.
“Approvals of liquid biopsy tests make it possible to deliver highly individualized health care for patients,” said Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices 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.”
With the cobas EGFR Mutation Test v2, the presence of specific NSCLC mutations [exon 19 deletion or exon 21 (L858R) substitution mutations] detected in patients’ blood samples aids in selecting those who may benefit from treatment with erlotinib. However, if such mutations are not detected in the blood, then a tumour biopsy should be performed to determine if the NSCLC mutations are present. Insofar as the test provides positive results, it may benefit patients who may be too ill or are otherwise unable to provide a tumour specimen for EGFR testing.
The efficacy of the cobas EGFR Mutation Test v2 using blood samples was determined by using the test to identify the EGFR mutation status in patients enrolled into a clinical trial whose tumour biopsies were previously confirmed positive for the EGFR exon 19 deletion or L858R mutations as determined by the cobas EGFR Mutation Test v1.
The FDA approved erlotinib in 2004 to treat patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen, and in 2013, the FDA approved it for the first-line treatment of patients with metastatic NSCLC whose tumours have EGFR exon 19 deletions or L858R substitution mutations as detected by an FDA-approved test. The most common side effects of erlotinib are rash, diarrhoea, anorexia, fatigue, dyspnoea, cough, nausea and vomiting. Erlotinib is not recommended for use in combination with platinum-based chemotherapy and the drug has not been evaluated as first-line treatment in patients with metastatic NSCLC whose tumours have EGFR mutations other than exon 19 deletions or L858R substitution mutations.
The cobas EGFR Mutation Test v2 is manufactured by Roche Molecular Systems.