Osimertinib for patients with EGFR T790M mutation-positive non-small-cell lung cancer and a poor performance status

Background: Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that is effective against EGFR T790M mutation-positive non-small-cell lung cancer (NSCLC) in patients who have good performance status (PS). However, the efficacy and safety of osimertinib for patients with poor PS is unknown. Methods: We retrospectively evaluated the efficacy and safety of osimertinib in patients with EGFR T790M mutation-positive NSCLC who had Eastern Cooperative Oncology Group PS scores of 2-4 and who were administered 80 mg of osimertinib once daily between March 2016 and February 2017. Results: Thirty patients (8 men and 22 women) with EGFR T790M mutation-positive NSCLC were evaluated; their median age was 66 years (range: 39-89 years). Twenty-four and six patients had PS scores of 2 and 3, respectively; none had a PS score of 4. All patients had previously been treated with first-or second-generation EGFR-TKIs. T790M was detected in the tumor samples of 23 patients, the blood samples of two patients, and both the tumor and blood samples of five patients. The overall response rate was 53% (95% confidence interval: 36-70%), and the PS score improvement rate was 63%. The median progression-free survival was 8.2 months (95% confidence interval: 4.3-13.2 months), while the median overall survival time was not reached. No patient required treatment cessation owing to adverse events, and no treatment-related deaths occurred. Conclusions: Osimertinib therapy demonstrates promising efficacy and acceptable safety in patients with EGFR T790M mutation-positive NSCLC who have poor PS.