title: Effect of EGFR-TKI retreatment following chemotherapy for advanced non-small cell lung cancer patients who underwent EGFR-TKI.
abstract: OBJECTIVE
  Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR)-activating mutations have higher response rate and more prolonged survival following treatment with single-agent EGFR tyrosine kinase inhibitor (EGFR-TKI) compared with patients with wild-type EGFR. However, all patients treated with reversible inhibitors develop acquired resistance over time. The mechanisms of resistance are complicated. The lack of established therapeutic options for patients after a failed EGFR-TKI treatment poses a great challenge to physicians in managing this group of lung cancer patients. This study evaluates the influence of EGFR-TKI retreatment following chemotherapy after failure of initial EGFR-TKI within at least 6 months on NSCLC patients.
  
  
  METHODS
  The data of 27 patients who experienced treatment failure from their initial use of EGFR-TKI within at least 6 months were analyzed. After chemotherapy, the patients were retreated with EGFR-TKI (gefitinib 250 mg qd or erlotinib 150 mg qd), and the tumor progression was observed. The patients were assessed for adverse events and response to therapy. Targeted tumor lesions were assessed with CT scan.
  
  
  RESULTS
  Of the 27 patients who received EGFR-TKI retreatment, 1 (3.7%) patient was observed in complete response (CR), 8 (29.6%) patients in partial response (PR), 14 (51.9%) patients in stable disease (SD), and 4 (14.8%) patients in progressive disease (PD). The disease control rate (DCR) was 85.2% (95% CI: 62%-94%). The median progression-free survival (mPFS) was 6 months (95% CI: 1-29). Of the 13 patients who received the same EGFR-TKI, 1 patient in CR, 3 patients in PR, 8 patients in SD, and 2 patients in PD were observed. The DCR was 84.6%, and the mPFS was 5 months. Of the 14 patients who received another EGFR-TKI, no patient in CR, 6 patients in PR, 6 patients in SD, and 2 patients in PD were observed. The DCR was 85.7%, and the mPFS was 9.5 months. Significant difference was found between the two groups in PFS but not in response rate or DCR.
  
  
  CONCLUSIONS
  Retreatment of EGFR-TKIs can be considered an option after failure of chemotherapy for patients who were previously controlled by EGFR-TKI treatment.
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Guo-Hao
authors.initials: GH
authors.lastname: Xia
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Shao-Rong
authors.initials: SR
authors.lastname: Yu
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Mei-Qi
authors.initials: MQ
authors.lastname: Shi
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Sun
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Xin-En
authors.initials: XE
authors.lastname: Huang
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Medical Oncology, Jiangsu Cancer Hospital, Nanjing 210009, China.
authors.forename: Ji-Feng
authors.initials: JF
authors.lastname: Feng
keywords: Non-small cell lung cancer (NSCLC); acquired resistance; chemotherapy; epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI); erlotinib; gefitinib