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Vladimir Mikchailovich Moiseenko

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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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      P2.14-30 - Predictive Value of ctDNA in Patients with EGFR Positive NSCLC Receiving 3rd Generation TKI (ID 1954)

      10:15 - 18:15  |  Author(s): Vladimir Mikchailovich Moiseenko

      • Abstract


      The third generation TKI (osimertinib) according to AURA III trial results achieved longer PFS compared to standard platinum based chemotherapy in patient’s resistant to 1-2 generation TKIs due to T790M mutation (8.5 vs 4.2 months). The evolution of resistance profile during thins therapy can be analyzed based on ctDNA.


      In this study patients with metastatic EGFR mutated NSCLC, with a confirmed disease progression during treatment with 1/2 generation TKIs, T790M positive which included patients received osimertinib 80 mg daily. Before the treatment and then every 2 months, whole blood was taken, for qualitative assessment of ctDNA dynamics by RT-PCR. The aim of the study was to assess the relationship between the disappearance of T790M + ctDNA and the time to progression on osimertinib.


      From August 2016 to December 2018 22 patients with T790M positive progression were identified. 18/22 (81.9%) were women, 4/22 (18.1%) - men. The mean age was 61.2 years (50-75). Only 1/22 had a smoking history > 30 pack/years. Primary activating mutations in EGFR gene were ex19del, L858R and G719S + S768I in 16, 5 and 1 patients respectively. Median PFS on the first line TKI was 21.7 months (CI 95%, 10.8 – 53.3). In 59.1% (13/22) progressive disease was characterized by the appearance of new metastases and in 40.9% (9/22) by the growth of previously identified metastases. 22 patients were evaluable for response. PR and SD were achieved in 11/20 (50%) and 10/20 (45/5%) respectively. Median PFS was in a whole group 16.7 months (CI 95%, 11.4 - 22.0). T790M in ctDNA was negative after 2 months of osimertinib treatment in 12/22 patients. Median PFS was 18.9 months (CI 95%, 14.8–19.7) in patients with undetectable T790M in ctDNA after 2 month of therapy compared to 8.0 months (CI 95%, 4.2 – 11.8) in patients remaining ctDNA T790M positive. No clinical factors were associated with the disappearance of ctDNA by statistical analysis.


      The disappearance of T790M + ctDNA after 2 months osimertinib therapy is predictive of greater PFS in patients with EGFR mutation positive NSCLC, receving of 2nd line.