A Prospective Observational Study of Osimertinib for Chemo-Naive Elderly Patients with EGFR Mutation-Positive Non-Small Cell Lung Cancer

Background: The clinical outcomes of elderly patients with EGFR-mutated non-small cell lung cancer (NSCLC) who are treated with osimertinib have not been sufficiently evaluated. This study aimed to assess the efficacy and safety of osimertinib in elderly chemotherapy-naive patients with NSCLC harboring sensitive EGFR mutations. Patients and Methods: We assessed the clinical effects of osimertinib as a first-line treatment for elderly NSCLC patients (>= 75 years of age) with an exon 19 deletion or exon 21 L858R mutation in EGFR. All patients were administered 80 mg/day osimertinib as initial treatment. Results: Forty-three patients (24 women and 19 men) with adenocarcinoma who were treated between August 2018 and July 2021 were included in this study; their median age was 79 years (range, 75-90 years). The overall objective response rate was 60.5%. The median progression-free survival (PFS) and time to treatment failure (TTF) of the entire patient population were 22.1 months and 14.6 months, respectively. The most common adverse event was rash acneiform (42%), followed by diarrhea (33%) and paronychia (28%); none of these were grades >= 3. Interstitial lung disease developed in 8 patients (18.6%); however, no treatment-related deaths occurred. Multivariate analysis identified performance status and disease stage as predictors of PFS and TTF. Conclusion: Considering the findings of this study and despite an observed discordance between PFS and TTF, osimertinib appears to be an effective and safe treatment option in elderly patients with advanced NSCLC harboring sensitive EGFR mutations. To obtain conclusive results, further studies in a larger elderly population are warranted.