*2.1. Patients*

The study eligibility and exclusion criteria have been previously reported [19,20]. Patients were enrolled in this study between July 2016 and May 2018 if they met the following eligibility criteria: recurrence of NSCLC after achieving stable disease or better as their best overall response after treatment with the first- and second-generation of EGFR-TKIs; harboring an EGFR mutation (activating) and being T790M-positive; aged over 75 years; performance status of ≤1 based on the Eastern Cooperative Oncology Group (ECOG) scale; adequate bone marrow function (leukocyte count 3000–12,000/μL, platelet count ≥100,000/μL, and hemoglobin level ≥9.0 g/dL), adequate hepatic function (bilirubin level ≤1.5 mg/dL, aspartate aminotransferase of ≤100 IU/L, alanine aminotransferase of ≤100 IU/L), and adequate renal function (serum creatinine ≤2.0 mg/dL); a measurable lesion according to the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines version 1.1; and provision of written informed consent. The exclusion criteria were pulmonary disorders; including idiopathic pulmonary fibrosis; interstitial pneumonia; pneumoconiosis; active radiation pneumonitis and drug-induced pneumonia, active infection; symptomatic brain metastasis; uncontrollable diabetes mellitus or severe comorbidities such as heart disease or renal disease; watery diarrhea; active concomitant malignancy; pregnancy or other medical problems that could prevent compliance with the protocol. The trial protocol was registered at Japan Registry of Clinical Trials (jRCTs071180002) and was approved by the ethical review board of Clinical Research Network Fukuoka Certified Review Board (CRB7180004). All patients provided written informed consent before enrollment.
