Updated Molecular Analyses in NSCLC Patients Treated With Erlotinib
In patients with non–small cell lung cancer (NSCLC), epidermal growth factor receptor (EGFR) genotype and copy number were associated with outcomes, in a landmark study of erlotinib, according to research published by Frances Shepherd, MD, of Princess Margaret Cancer Centre, and colleagues, in the Journal of Clinical Oncology.
Since the predictive value of EGFR mutations or high copy number on survival has remained unclear, the researchers re-evaluated patients from the BR.21 trial, which demonstrated significant survival benefit from erlotinib for patients with NSCLC. They analyzed samples for EGFR mutations (n=204), KRAS mutations (n=206), and EGFR copy number (n=159) using a fluorescence-based polymerase chain reaction (PCR) technique and ScorpionIM kits, since the sensitivity of PCR-sequencing to detect EGFR mutations may be suboptimal.
The overall mutation rate in all patients was 17%. The response rate was 27% for EGFR-mutated patients and 7% for wild-type patients (P=.03). EGFR amplification was both prognostic for poorer survival (P=.005) and predictive of a differential survival benefit from erlotinib (P=.009), the investigators reported. EGFR and KRAS mutations were not significant prognostic or predictive markers.