Erlotinib response of EGFR-mutant gefitinib-resistant non-small-cell lung cancer.
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.
Chang
John Wen-Cheng
JW
Department of Hematology-Oncology, Chang Gung Memorial Hospital, Taoyuan, Taiwan. wen1902@hotmail.com
Chou
Chun-Liang
CL
Huang
Shiu-Feng
SF
Wang
Hung-Ming
HM
Hsieh
Jia-Juan
JJ
Hsu
Todd
T
Cheung
Yun-Chung
YC
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
D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D066246:ErbB Receptors; D000077156:Gefitinib