Real-world treatment outcomes in South Korean patients with epidermal growth factor receptor-mutant non-small cell lung cancer.

BACKGROUND/AIMS: This study aimed to assess the real-world treatment outcomes in South Korean patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) receiving first-line (1L) EGFR tyrosine kinase inhibitors (TKIs). METHODS: We used the Health Insurance Review and Assessment Service database, which includes the data of a large proportion of the Korean population. Patients with EGFR-positive NSCLC who received gefitinib, erlotinib, or afatinib as the 1L treatment between 2012 and 2018 were included. Survival outcomes, subsequent therapies, and treatment patterns were analyzed. RESULTS: Among the 9,478 patients included, gefitinib (56.68%) was the most commonly prescribed 1L EGFR-TKI, followed by afatinib (25.30%) and erlotinib (18.02%). The median time to next treatment was 16.4 to 18.8 months. Overall survival (OS) was significantly different among the three treatment groups; the median OS was 28.8, 25.3, and 23.9 months for patients who were treated with afatinib, gefitinib, and erlotinib, respectively (p < 0.001). For the patients who received second-line (2L) therapy (n = 4,904, 51.74%), pemetrexed monotherapy was most commonly used (47.70%), followed by osimertinib (21.59%). Patients who received osimertinib as the 2L treatment had longer OS compared to those receiving pemetrexed (median OS: not reached vs. 25.3 to 28.8 months). CONCLUSION: Our real-world study demonstrated survival outcomes that were comparable to those observed in clinical trials for patients with EGFR-mutant NSCLC treated with EGFR-TKIs. Detection of the acquired T790M mutation and subsequent osimertinib treatment had significant prognostic value.