Multicenter phase 2 trial of first-line osimertinib for metastatic non-small cell lung cancer with uncommon EGFR mutations

Non-small cell lung cancer (NSCLC) with uncommon EGFR mutations is a rare subgroup, composing 14% of all EGFR mutations in NSCLC. The multicenter phase 2 UNICORN trial in Japan evaluated first-line osimertinib for metastatic NSCLC with uncommon EGFR mutations other tan exon 20 insertion mutations. The trial included 40 patients. First-line osimertinib resulted in an overall response rate of 55.0%, median progression-free survival of 9.4 months, and median duration of response of 22.7 months. Grade 3 or 4 adverse events were reported for 27.5% of patients, and 12.5% developen interstitial lung disease. All adverse events were manageable, and there were no treatment-related deaths. The authors conclude that osimertinib showed clinical activity with manageable toxic effects among previously untreated patients with metastatic NSCLC harboring uncommon EGFR mutations other than exon 20 insertion mutations.