Author of

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  P2.13 - Targeted Therapy (Not CME Accredited Session) (ID 962)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall

  • 27196

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    P2.13-22 - Resistant Patterns to Osimertinib in Non-Small Cell Lung Cancer Patients with Both T790M and Sensitizing EGFR Mutation (ID 12655)

    16:45 - 18:00  |  Author(s): Sei-Hoon Yang
    • Abstract
    • Slides

    Background
    

    Osimertinib is a 3rd generation, EGFR-TKI which is active for both sensitizing mutations and T790M of EGFR. Although it has proven its efficacy, the acquired resistance eventually occurs requiring the investigation for resistant mechanisms to provide overcoming strategies.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    We retrospectively reviewed the medical records of T790M+ lung cancer patients treated with osimertinib after acquiring resistance to 1^st- or 2^nd generation EGFR-TKI between February 2016 and June 2017 to evaluate the efficacy and safety of the drug. In addition, the moleculo-pathologic data of re-biopsy samples after the development of resistance to osimertinib were analyzed.

    4c3880bb027f159e801041b1021e88e8 Result
    

    In 23 patients included, the median age was 59.0 years and thirteen (56.5%) were female. The median duration of follow-up was 11.9 months. 17 patients achieved an objective response (73.9%) and the disease was controlled in 22 patients (95.7%). Median progression-free survival was 7.4 months (95% CI 3.6-11.0) and median overall survival was not reached. The adverse effects were minimal except one case of severe pneumonitis. Among 14 patients who finally experienced the disease progression during osimertinib, the re-biopsy was performed in 10 patients. T790M disappeared in 7 patients (70%) and one of them showed the wild-type conversion. Transformation to small cell carcinoma was observed in 2 patients who responded to chemotherapy with etoposide and cisplatin. A newly developed C797S mutation was detected in one patient. Interestingly, C797S disappeared after 6 cycles of pembrolizumab following osimertinib-resistance and the patient responded well to osimertinib again.

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    Osimertinib showed the clinical activity and the favorable toxicity profile comparable to those of clinical trials in real world practice in Korea. The evaluation with repeated biopsy sample after osimertinib-resistance is needed to guide the following treatment strategy.

    6f8b794f3246b0c1e1780bb4d4d5dc53

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