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Toshihiro Nukiwa



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    P2.14 - Targeted Therapy (ID 183)

    • Event: WCLC 2019
    • Type: Poster Viewing in the Exhibit Hall
    • Track: Targeted Therapy
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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      P2.14-52 - The Results from Plasma EGFR Mutation Analysis in NEJ026 Study (ID 602)

      10:15 - 18:15  |  Author(s): Toshihiro Nukiwa

      • Abstract

      Background

      EGFR mutation analysis of plasma circulating tumor DNA (ctDNA) has been reported to be useful to detect resistant mutations and to predict the efficacy of treatment. In NEJ026 study, we demonstrated the PFS of erlotinib plus bevacizumab (BE) treatment was significantly superior to the erlotinib alone (E) in NSCLC patients harboring EGFR mutation. Evaluation of plasma EGFR mutations included in NEJ026 study as preplanned analysis.

      Method

      At the time points of pretreated (P0), 6 weeks after study treatment started (P1), and confirmed progressive disease (P2), the plasma samples were collected from the patients enrolled to NEJ026 study. The number of enrolled patients were 112 in BE and 114 in E. Plasma ctDNA analysis for detection of the activating EGFR mutation and T790M mutation were performed by modified PNA-LNA PCR clamp method.

      Result

      The total numbers of collected plasma samples in BE and E were 108 (96.4%) and 107 (95.5%) at P0, 95 (84.8%) and 97 (86.6%) at P1, and 42 (37.5%) and 53 (47.3%) at P2, respectively. In eligible patients having EGFR activating mutation detected by cytohistological specimens, detection rate of plasma EGFR mutation at P0 was 68% (147/215). The detection ratio of T790M mutation at P2 were similar in both arms: 8 (19.0%) in BE and 11 (20.8%) in E. By detection pattern of activating EGFR mutation, PFS was evaluated among three groups: type A (P0 (-),P1 (-)), type B (P0 (+), P1(-)), and type C (P0 (+), P1(+)). Type A achieved the best response to both TKI [Type A BE: 18.1 M (n = 32, 95% CI, 11.5 to upper limit not reached(NR)), E: 16.7 M (n = 26, 95% CI, 11.2 to NR )]. Type B also had better PFS to TKI and BE is more favorable effect than E compared to other types [type B BE: 15.5 M (n = 48, 95% CI, 12.4 to 23.3), E: 11.1 M (n = 57, 95% CI, 8.5 to 13.7)]. Type C showed worse response to both treatment [type C BE: 6.0M. (n = 12, 95% CI 2.6 to NR), E: 4.3 M (n = 10, 95% CI, 2.8 to 20.2)]. BE had better PFS in all types.

      Conclusion

      Frequency of T790M in P2 was similar among BE and E. When patients still had detectable activating EGFR mutation in plasma ctDNA after treatment for 6 weeks, you should consider that they might have poor response to both BE and E.