Author of

• 11543

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  P2.06 - Poster Session 2 - Prognostic and Predictive Biomarkers (ID 165)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11553

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    P2.06-010 - Analytical Performance of the cobas EGFR Mutation Assay for Japanese Non-Small Cell Lung Cancer (ID 1101)

    09:30 - 09:30  |  Author(s): S. Shimizu
    • Abstract

    Background
    Patients’ EGFR mutation status prior to treatment impacts outcomes and, EGFR testing has been developed as a companion diagnostic; this relationship between therapeutic and diagnostic agents is known as personalized healthcare. Recently, it was reported that about half of patients may acquire resistance to EGFR-TKIs following therapy, mainly by appearance of EGFR mutations, such as T790M. Thus, it is important to assess EGFR mutation status before and during treatment to determine the most appropriate treatment regimens for patients. A number of PCR-based techniques are used in the assessment of EGFR mutations. In Japan, the “Scorpion-ARMS” therascreen® EGFR Rotor-Gene Q PCR Kitis (therascreen EGFR assay) the only available in vitro diagnostic (IVD) test. The cobas® EGFR Mutation Test (cobas EGFR assay) is the only FDA-approved kit for IVD testing in the US.In this study, we compared the performance of the cobas EGFR assay and the therascreen® EGFR assay using FFPE tissue specimens from NSCLC patients.

    Methods
    We extracted DNA from 149 FFPE tissues of NSCLC, according to the manufacturer’s instructions and performed a comparative study of cobas EGFR and therascreen EGFR methods.

    Results
    EGFR mutations were identified in 63 NSCLC specimens (42.3%) using the cobas EGFR assay and 61 samples (41.2%) using the therascreen EGFR assay. The concordance rate between the cobas EGFR assay and therascreen EGFR assays was 145/149 (97.3%). Only three discordants between these EGFR assays were observed. One T790M mutation in combination with an L858R mutation was identified by the cobas EGFR assay. No invalid assay results occurred with the cobas EGFR assay.

    Conclusion
    The cobas EGFR assay has two advantages. One is that the process is easily performed by stable methods. It takes only 8 hours, from tumor specimen to results generated using the semi-automated system. Thus, patients assessed using the cobas EGFR assay can begin the most appropriate treatment quickly. The other advantage is that only a very small amount of DNA (150 ng) is required to detect mutation status using the cobas EGFR assay. Our results show a high concordance rate (97.3%) of cobas EGFR with an existing IVD product, the therascreen EGFR assay. In this study, one double mutant, T790M in combination with L858R, was only identified by the cobas EGFR assay. The cobas EGFR assay appears to give the most accurate and appropriate results for NSCLC patients.