Retreatment after the failure of initial epidermal growth factor receptor inhibitor in non-small cell lung cancer.

Abstract

e18048 Background: The epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) including gefitinib and erlotinib shows favorable antitumor activity against cheomrefractory non small cell lung cancer (NSCLC). More recently, EGFR-TKI also shows antitumor activity in first-line therapy. However, patients with advanced NSCLC have few treatment options available if they are refractory to EGFR-TKI. Methods: This study retrospectively analyzed 71 patients who experienced treatment failure from their initail use of EGFR-TKI. After more than 1 month from the time of discontinuation of the initial TKI treatmenT, they were retreated with TKI as further tumor progression was observed. Results: Of the 71 patients, 26 (36.6%) patients were well controlled by retreatment with TKI monotherapy for more than 3 months. 5 (7.1%) patients had partial response. Exon 21 mutation, PFS more than 6 months during initial treatment TKI, and the interval more than 3months between initial treatment and retreatment with TKI was associated with a good progression free survival based on univariate Cox analysis (P=0.034; P=0.013; P=0.046). Conclusions: This study suggest the possibility that retreatment with TKI might be useful when 1) initial treatment shows a favorable PFS(more than 6 months), and 2) there has been a period of time (more than 3 months) following the termination of the initial TKI treatment, and 3) Exon 21 has active mutation.