Author of

• 18374

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  P3.02b - Poster Session with Presenters Present (ID 494)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 18487

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    P3.02b-113 - Clinical Course of NSCLC Patients with EGFR Mutation Undergoing Rebiopsy and Osimertinib Therapy (ID 5272)

    14:30 - 14:30  |  Author(s): K. Watanabe
    • Abstract

    Background:
    Osimertinib, a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), was approved in May 2016 in Japan. Its administration requires a tumor rebiopsy to detect the EGFR T790M mutation. AURA and AURA2 studies with 411 patients demonstrated a remarkable clinical outcome with an overall response rate (ORR) of around 65% and progression-free survival (PFS) of 9.7 months. Several authors reported that the detection rate of T790M by tumor rebiopsy in these patients was approximately 52 to 68%. However, thorough accumulation of data is required to establish the clinical relevance of T790M detection and osimertinib response.
    
    Methods:
    We retrospectively reviewed the clinical courses of NSCLC patients with the EGFR mutation, who had undergone rebiopsies and osimertinib therapy.
    
    Results:
    Eleven patients with the EGFR mutation (exon19del [n=10] and L858R [n=1]) were included. Average age was 67 years old (range 53–79). The following EGFR-TKIs were administered to the 11 patients before rebiopsy; elrotinib (n=6), afatinib (n=5) and gefitinib (n=2). The patients received rebiopsy in the 2nd line treatment (n=3), 3rd line (n=2), 5th line (n=2), 6th line (n=2) and 7th line (n=2). Rebiopsy sites were primary lung tumors (n=8), supraclavicular lymph node (n=1), liver metastasis (n=1) and pleural effusion (1). Among them, T790M was detected in four, zero, one, and one, respectively (detection rate: 54.5%). Rebiopsy was successfully performed in all patients, among whom one required a second attempt. ASP8273, another third-generation EGFR-TKI, and osimertinib were administered in one and two patients, respectively. The remaining two patients are to be treated with osimertinib. Both patients who received osimertinib achieved partial response, and their ECOG performance status (PS) was remarkably improved from 4 to 1, and 3 to 1. One of the two patients experienced grade 4 neutropenia; thus, the osimertinib dose was reduced from 80 mg to 40 mg daily. The remaining patient suffered from erythema; however, it was improved after ten-day cessation of medication. Osimertinib was then resumed at 80 mg daily with no severe side effects experienced thereafter.
    
    Conclusion:
    The detection rate of T790M by rebiopsy was consistent with previous reports. Osimertinib was feasible and effective for our patients with poor PS; however, a prospective study is required to confirm osimertinib’s validity for such patients. In WCLC 2016, we will increase the number of patients who undergo rebiopsy and osimertinib therapy, and we hope to demonstrate detailed detection patterns of T790M, as well as ORR and PFS.