title: Erlotinib response of EGFR-mutant gefitinib-resistant non-small-cell lung cancer.
abstract: OBJECTIVE
  Failure to gefitinib is generally believed to be associated with cross-resistance to other epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI). Here we report a case whose active EGFR-mutant NSCLC responded to erlotinib treatment.
  
  
  METHODS
  Lung specimen was obtained during diagnostic procedures from a 41-year-old Taiwanese male smoker with adenocarcinoma. He received cisplatin-based chemotherapy following craniotomy to remove his brain metastasis. Tumor progressed in both lung and left adrenal gland. He underwent second-line docetaxel chemotherapy. Tumor progressed again 7 months later. He was subsequently treated with gefitinib 250mg QD. Complete regression of the lung tumor and partial response of the left adrenal gland mass was achieved. Nine months later, the left lower lobe lung tumor and left adrenal gland tumor progressed. A lung biopsy from the left lower lobe disclosed an adenocarcinoma which harbored an in-frame deletion in exon 19 (heterozygous delE746-A750) of EGFR without a second mutation such as T790M in exon 20. Subsequent erlotinib 150mg QD was administered. He experienced grade 1 skin rash, diarrhea and paronychia following erlotinib.
  
  
  RESULTS
  This patient achieved a partial response to erlotinib treatment. He remained on erlotinib for a total of 18 months until the left adrenal gland tumor progressed.
  
  
  CONCLUSIONS
  This case demonstrated that NSCLC bearing in-frame deletion in exon 19 of EGFR may respond to erlotinib treatment following gefitinib failure.
authors.affiliation: Department of Hematology-Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan. wen1902@hotmail.com
authors.forename: John Wen-Cheng
authors.initials: JW
authors.lastname: Chang
authors.forename: Chun-Liang
authors.initials: CL
authors.lastname: Chou
authors.forename: Shiu-Feng
authors.initials: SF
authors.lastname: Huang
authors.forename: Hung-Ming
authors.initials: HM
authors.lastname: Wang
authors.forename: Jia-Juan
authors.initials: JJ
authors.lastname: Hsieh
authors.forename: Todd
authors.initials: T
authors.lastname: Hsu
authors.forename: Yun-Chung
authors.initials: YC
authors.lastname: Cheung
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D066246:ErbB Receptors / Q000737:chemistry / Q000235:genetics*; D000069347:Erlotinib Hydrochloride; D000077156:Gefitinib; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D008297:Male; D009154:Mutation; D011799:Quinazolines / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed
chemical_list: D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D000077156:Gefitinib