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Defining EGFR amplification status for clinical trial inclusion.

ABSTRACT: BACKGROUND:Precision medicine trials targeting the epidermal growth factor receptor (EGFR) in glioblastoma patients require selection for EGFR-amplified tumors. However, there is currently no gold standard in determining the amplification status of EGFR or variant III (EGFRvIII) expression. Here, we aimed to determine which technique and which cutoffs are suitable to determine EGFR amplification status. METHODS:We compared fluorescence in-situ hybridization (FISH) and real-time quantitative (RT-q)PCR data from patients screened for trial inclusion into the Intellance 2 clinical trial, with data from a panel-based next generation sequencing (NGS) platform (both DNA and RNA). RESULTS:By using data from >1000 samples, we show that at least 50% of EGFR amplified nuclei should be present to define EGFR gene amplification by FISH. Gene amplification (as determined by FISH) correlates with EGFR expression levels (as determined by RT-qPCR) with receiver operating characteristics analysis showing an area under the curve of up to 0.902. EGFR expression as assessed by RT-qPCR therefore may function as a surrogate marker for EGFR amplification. Our NGS data show that EGFR copy numbers can strongly vary between tumors, with levels ranging from 2 to more than 100 copies per cell. Levels exceeding 5 gene copies can be used to define EGFR-amplification by NGS; below this level, FISH detects very few (if any) EGFR amplified nuclei and none of the samples express EGFRvIII. CONCLUSION:Our data from central laboratories and diagnostic sequencing facilities, using material from patients eligible for clinical trial inclusion, help define the optimal cutoff for various techniques to determine EGFR amplification for diagnostic purposes.

SUBMITTER: French PJ

PROVIDER: S-EPMC6784284 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Defining EGFR amplification status for clinical trial inclusion.

French Pim J PJ Eoli Marica M Sepulveda Juan Manuel JM de Heer Iris I Kros Johan M JM Walenkamp Annemiek A Frenel Jean-Sebastien JS Franceschi Enrico E Clement Paul M PM Weller Michael M Ansell Peter P Looman Jim J Bain Earle E Morfouace Marie M Gorlia Thierry T van den Bent Martin M

Neuro-oncology 20191001 10

<h4>Background</h4>Precision medicine trials targeting the epidermal growth factor receptor (EGFR) in glioblastoma patients require selection for EGFR-amplified tumors. However, there is currently no gold standard in determining the amplification status of EGFR or variant III (EGFRvIII) expression. Here, we aimed to determine which technique and which cutoffs are suitable to determine EGFR amplification status.<h4>Methods</h4>We compared fluorescence in-situ hybridization (FISH) and real-time qu ...[more]

PMID: 31125418

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Project description:Background HER2 (or ERBB2) amplification is an important mechanism for acquired resistance to EGFR tyrosine kinase inhibitors (TKI). The benefits of HER2-targeted therapy have been limited. Herein, we investigated the molecular and clinical patterns of HER2 amplification in non-small cell lung cancer (NSCLC) patients during progression on EGFR-TKIs and the potential of combining EGFR-TKI and pyrotinib to overcome resistance. Methods In this study, 1,637 NSCLC cases from Geneseeq after progression of EGFR-TKIs were screened and analyzed by next generation sequencing (NGS), in which 48 patients with HER2 amplification were eligible and enrolled. A total of 403 patients from Sun Yat-sen University Cancer Center (SYSUCC) were screened and five patients with concomitant EGFR mutations and HER2 amplification were retrospectively collected to assess the effect of afatinib or combination of EGFR-TKI and pyrotinib. Results In the 48 patients from the Geneseeq cohort, 27 (56.2%) patients suffered from resistance of 1st/2nd generation EGFR-TKI, and 21 (43.8%) patients from 3rd generation. As for the five patients forming the SYSUCC cohort, three patients were treated with afatinib, one achieved partial response (PR) with progression-free survival (PFS) of 6 months and two quickly developed disease progression. Two patients were treated with EGFR-TKIs plus pyrotinib, one receiving gefitinib plus pyrotinib achieved PR with PFS of 8 months and benefited from osimertinib plus pyrotinib for 3 months till data-off; one receiving osimertinib plus pyrotinib achieved SD for 4 months till data-off. The most common co-occurring alteration was TP53 (91.7%) in the mutation profile of the 48 patients from the Geneseeq cohort, and four patients had TP53 co-mutations of the five patients from the SYSUCC cohort. Conclusion In this study, we detected 7% HER2 amplification present in EGFR-TKIs resistance. Patients with concomitant EGFR mutation and HER2 amplification may derive clinical benefit from therapies that target both EGFR and HER2.

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Defining EGFR amplification status for clinical trial inclusion.

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Defining EGFR amplification status for clinical trial inclusion.

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