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ABSTRACT: Background
The clinicopathologic characteristics, acquired resistance patterns, and outcomes among patients with atypical EGFR mutations and HER2 alterations remain underexplored.Patients and methods
A single-center retrospective review was conducted. Oncogenes assessed include typical EGFR (t-EGFR; exon 19 del and L858R), atypical EGFR (a-EGFR; G719X, exon 20, L861Q), HER2 (exon 19, exon 20, amplifications), gene fusions (ALK, ROS1, RET), RAS (KRAS, NRAS), and RAF (BRAF V600E). Progression-free survival (PFS), overall survival (OS), disease control rate, and objective response rate (Response Evaluation Criteria in Solid Tumors 1.1) were collected.Results
Among 570 patients, we found 55 a-EGFR mutations (13 G719X, 38 exon 20, 4 L861Q) and 31 HER2 alterations (2 exon 19 mutations, 27 exon 20 insertions, 2 amplifications). Patients with EGFR and HER2 alterations had increased lung and bone metastases relative to patients with gene fusions, RAS/RAF mutations, and no identified driver oncogenes (P < .001). Patients with EGFR exon 20 insertions had a median PFS to EGFR tyrosine kinase inhibitors (TKIs) of 5 months and an OS of 16 months-significantly worse than exon 19 del and L858R (Bonferroni correction; P < .001), but not G719X or L861Q. Relative to t-EGFR mutations, T790M and MET amplification occurred less frequently as acquired resistance mechanisms among a-EGFR samples (P < .001). Ten patients with a-EGFR mutations and HER2 alterations received single-agent immune checkpoint inhibitors (ICIs) with no radiographic responses and a median PFS of 2 months.Conclusion
EGFR and HER2-mutated NSCLC have a high rate of synchronous lung and bone metastases. Patients with a-EGFR mutations have inferior responses to EGFR-directed therapies with lower rates of acquired T790M and MET amplification. Responses to ICIs are uniformly poor. Novel therapeutic approaches are needed.
SUBMITTER: Patil T
PROVIDER: S-EPMC7442280 | biostudies-literature | 2020 May
REPOSITORIES: biostudies-literature
Patil Tejas T Mushtaq Rao R Marsh Sydney S Azelby Christine C Pujara Miheer M Davies Kurtis D KD Aisner Dara L DL Purcell William T WT Schenk Erin L EL Pacheco Jose M JM Bunn Paul A PA Camidge D Ross DR Doebele Robert C RC
Clinical lung cancer 20191121 3
<h4>Background</h4>The clinicopathologic characteristics, acquired resistance patterns, and outcomes among patients with atypical EGFR mutations and HER2 alterations remain underexplored.<h4>Patients and methods</h4>A single-center retrospective review was conducted. Oncogenes assessed include typical EGFR (t-EGFR; exon 19 del and L858R), atypical EGFR (a-EGFR; G719X, exon 20, L861Q), HER2 (exon 19, exon 20, amplifications), gene fusions (ALK, ROS1, RET), RAS (KRAS, NRAS), and RAF (BRAF V600E). ...[more]