Author of

• 20167

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  P2.03 - Chemotherapy/Targeted Therapy (ID 704)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Chemotherapy/Targeted Therapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23316

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    P2.03-045 - Updated Results of Phase II, Liquid Biopsy Study in EGFR Mutated NSCLC Patients Treated with Afatinib (WJOG 8114LTR) (ID 9715)

    09:30 - 09:30  |  Author(s): K. Azuma
    • Abstract

    Background:
    Liquid biopsy has been approved as an optional method to detect clinically relevant EGFR mutations in NSCLC. WJOG8114LTR is a prospective, multi-institutional study of liquid biopsy in EGFR mutated NSCLC patients. Previously, we reported that complete molecular response at 4 weeks could be an early surrogate marker of durable efficacy. Here, we report updated results.
    
    Method:
    Chemotherapy naïve, advanced NSCLC patients with EGFR-sensitizing mutation received afatinib monotherapy (40 mg/body) until progressive disease (PD) or unacceptable toxicity. Plasma DNA was obtained from patients at baseline, weeks 2, 4, 8, 12, 24, 48, and at PD. Three types of clinically relevant EGFR mutations (exon 19 deletion, exon 20 T790M and exon 21 L858R) will be analyzed using plasma DNA with multiplexed, pico-droplet digital PCR assay (RainDrop® system, RainDance Technologies, Billerica, MA). Complete molecular response (CMR) was defined as mutant allele event/frequency of exon 19 deletion or exon 21 L858R below the cutoff for the positivity by digital PCR in plasma. This study was registered at UMIN (ID: 000015847).
    
    Result:
    Fifty-seven patients were registered in the study. Efficacy of afatinib was comparable to previous reports (overall response rate: 78.6%, and median progression-free survival (mPFS): 14.2 months). At baseline, 62.5% of patients (35/56) were positive for EGFR mutation in plasma. Among those, CMR rate at 2, 4, 8, 12, 24 weeks was 60.6%, 87.5%, 93.8%, 87.1%, and 83.3%, respectively. About 40% of patients who achieved CMR at any time point maintain CMR at 48 weeks and had durable progression-free survival (more than 400 days). At the time of analysis, 17 patients experienced disease progression, and 14 plasma samples were collected. Of those, 8 (57.1%) were positive for mutation in plasma. In five patients, plasma progression was observed prior to radiological progression. Exon 20 T790M was detected in five patients (detection rate: 62.5%).
    
    Conclusion:
    Among EGFR mutated NSCLC patients, liquid biopsy was a useful method to predict durable efficacy and progression. Applicability of liquid biopsy should be explored in further study.