In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 31, No. 15_suppl ( 2013-05-20), p. e19099-e19099
Abstract:
e19099 Background: Patients (pts) with advanced NSCLC and sensitizing EGFR mutations who initially respond to gefitinib or erlotinib eventually develop acquired resistance to the TKIs. Our goal was to determine the effects of erlotinib 150 mg/d in EGFR mutated pts resistant to gefitinib 250 mg/d, because the EGFR TKI erlotinib is given at a higher biologically active dose than gefitinib. Methods: Retrospective review of 5 EGFR mutated (exon 19 deletions) patients that were given gefitinib and subsequently erlotinib. Results: All pts responded to gefitinib with median progression-free survival of 13 months (95% confidence interval, 4-16). After gefitinib resistance, 60% (3 of 5) of these pts displayed progressive disease while on erlotinib with progression-free survival of 2 months (95% confidence interval, 2-3). These pts acquired the T790M mutation. 2 gefitinib-resistant pts with the acquired L858R-L747S EGFR, which in vitro is sensitive to achievable serum concentrations of erlotinib 150 mg/d, achieved a partial response to erlotinib. In literature doesn’t exist a prospective study about the stratification of pts ordered by PS, age, gender, smoker/non-smoker, which could test the efficiency of the erlotinib after gefitinib in pts with different EGFR mutations. We only have at our disposal few studies control-case in non-selected pts which show a potential efficiency of erlotinib after the failure of the gefitinib, nevertheless, without an evident increase of the overall survival. Conclusions: In EGFR mutated tumors resistant to gefitinib 250 mg/d, a switch to erlotinib 150 mg/d does not lead to responses in most pts. These findings are consistent with preclinical models, because the common mechanisms of TKI resistance (T790M and MET amplification) in vitro are not inhibited by clinically achievable doses of gefitinib or erlotinib. Alternative strategies to overcome TKI resistance must be evaluated.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2013.31.15_suppl.e19099
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2013
detail.hit.zdb_id:
2005181-5
