Abstract 2521: Molecular profiling of T790M-negative NSCLC patients progressing on EGFR-TKI enrolled in the CL1-49076-003 trial with a MET/AXL/FGFR inhibitor in combination with gefitinib
Authors: Ibanez Monica Garzon , Ariza Nuria Jordana , Cao María González , Lladó Ruth Román , Bueno Alejandro Martínez , Landeira Lidia Alonso , Gil María de los Llanos , Vila Miguel Ángel Molina , Karachaliou Niki , Smutna Veronika , Cattan Valerie , Rosell Rafael , Viteri Santiago 
Published: August 2019

Abstract
Background Non-small cell lung cancer (NSCLC) tumors with mutations in the EGF receptor (EGFR) relapse to therapy with EGFR tyrosine kinase inhibitors (EGFR TKIs) due to a variety of mechanisms, such as emergence resistance mutations, dysregulation of AXL, MET, HER2 or FGFR1 receptors or histological transformation. The CL1-49076-003 trial of the MET/AXL/FGFR inhibitor S49076 in combination with gefitinib enrolled T790M-negative patients in progression to first-line EGF TKIs and showing dysregulation of MET and/or AXL. Molecular screening was performed in 47 patients, 23 of them met the molecular eligibility criteria and 14 were enrolled in the trial. Baseline biopsies of the 14 patients were submitted to molecular profiling.
Methods Ten patients had enough material available for Next Generation Sequencing (NGS), that was performed using the GeneRead QIAact Lung UMI Panel (Qiagen, Hilden, FRG). The panel included mutation detection in 16 genes, copy number variations in 5 and the MET exon 14 splicing variant. Amplifications detected by NGS were confirmed by FISH. Of the 4 patients with insufficient material for NGS, 3 were submitted to FISH for HER2 and MET and quantitative PCR for BRAF and PIK3CA hotspot mutations. Finally, of the remaining patient only FISH for MET could be performed.
Results Copy number gains were the most prevalent alterations in patients progressing to EGFR TKIs. Four of 14 evaluable patients (29%) showed MET amplification, 4/13 (31%) HER2 amplification and 3/10 (30%) EGFR copy number gains. FGFR1 amplifications were absent in the patient cohort. The baseline sensitizing mutation was confirmed in all cases. Two patients showed additional mutations that could be related to resistance, namely a p.G724S mutation in EGFR and a p.N784fs*2 mutation in MET. Remarkably, these two patients did not present gene amplifications. No other mutations were detected in the rest of genes analyzed, including BRAF, PIK3CA, KRAS, NRAS or ERBB2. Among the 4 patients with more than 6 months of progression free survival, 2 had MET amplifications. The patient with the p.G724S experienced rapid progression of target lesions.
Conclusion Next Generation Sequencing can be used to determine mechanisms of resistance to EGFR TKIs at progression, and can give useful clinical information in order to select therapies for second line treatment
Citation Format: Monica Garzon Ibanez, Nuria Jordana Ariza, María González Cao, Ruth Román Lladó, Alejandro Martínez Bueno, Lidia Alonso Landeira, María de los Llanos Gil, Miguel Ángel Molina Vila, Niki Karachaliou, Veronika Smutna, Valerie Cattan, Rafael Rosell, Santiago Viteri. Molecular profiling of T790M-negative NSCLC patients progressing on EGFR-TKI enrolled in the CL1-49076-003 trial with a MET/AXL/FGFR inhibitor in combination with gefitinib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2521.