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Ryoji Kato



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    MA03 - Clinomics and Genomics (ID 119)

    • Event: WCLC 2019
    • Type: Mini Oral Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Now Available
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      MA03.11 - Chemotherapy After PD-1 Inhibitors Versus Chemotherapy Alone in Patients with Non–Small Cell Lung Cancer (WJOG10217L) (Now Available) (ID 409)

      10:30 - 12:00  |  Author(s): Ryoji Kato

      • Abstract
      • Presentation
      • Slides

      Background

      Studies have suggested that chemotherapy after immune checkpoint inhibitors may confer an improved response in patients with non–small cell lung cancer (NSCLC). However, potential selection bias in such studies has not been addressed. We therefore applied propensity score analysis to investigate the efficacy of subsequent chemotherapy after PD-1 inhibitors (CAP) compared with chemotherapy alone.

      Method

      We conducted a multicenter retrospective cohort study for patients with advanced or recurrent NSCLC who were treated at 47 institutions across Japan between 1 April 2014 and 31 July 2017 with chemotherapy (docetaxel with or without ramucirumab; S-1; or pemetrexed) either after PD-1 inhibitor therapy (CAP cohort) or alone (control cohort). The primary end point was objective response rate (ORR). Inverse probability weighting (IPW) was applied to adjust for potential confounding factors, including age, sex, smoking status, performance status, histology, EGFR or ALK genetic alterations, brain metastasis, and recurrence after curative radiotherapy.

      Result

      A total of 1439 patients (243 and 1196 in the CAP and control cohorts, respectively) was available for unadjusted analysis. Several baseline characteristics—including age, histology, EGFR or ALK alterations, and brain metastasis—differed significantly between the two cohorts. After adjustment for patient characteristics with the IPW method, ORR was 18.9% for the CAP cohort and 10.8% for the control cohort (ORR ratio, 1.75; 95% confidence interval [CI], 1.25–2.45; P = .001). Median PFS was 3.5 and 2.6 months for the CAP and control cohorts, respectively (hazard ratio [HR], 0.862; 95% CI, 0.743–0.998; P = .048). The PFS rate at 3, 6, and 12 months was 53.3%, 28.5%, and 4.6%, respectively, for the CAP cohort, and 44.3%, 19.7%, and 6.1% for the control cohort. Median OS was 9.8 months for the CAP cohort and 10.3 months for the control cohort (HR, 0.979; 95% CI, 0.813–1.179; P = .822).

      Conclusion

      After adjustment for selection bias using propensity score–weighted analysis, CAP showed a significantly higher ORR and longer PFS compared with chemotherapy alone, with the primary end point of ORR being achieved. However, these results did not translate into an OS advantage, and no PFS benefit was apparent at 12 months despite the improvement observed at 3 and 6 months. Our findings suggest that prior administration of PD-1 inhibitors may result in a synergistic antitumor effect with subsequent chemotherapy, but that such an effect is transient. CAP therefore does not appear to achieve durable tumor control or confer a lasting survival benefit.

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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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      P2.14-15 - Impact of Coexisting Gene Mutations in EGFR-Mutated Non–Small Cell Lung Cancer Before Treatment on EGFR T790M Mutation Status After EGFR-TKIs (ID 1347)

      10:15 - 18:15  |  Author(s): Ryoji Kato

      • Abstract

      Background

      The T790M secondary mutation of epidermal growth factor receptor gene (EGFR) is the most common mechanism of acquired resistance to first- or second-generation EGFR tyrosine kinase inhibitors (TKIs). We investigated the association between gene mutation profile in EGFR mutation–positive non–small cell lung cancer (NSCLC) before EGFR-TKI treatment and T790M status after treatment.

      Method

      A total of 57 EGFR mutation–positive NSCLC patients who had undergone a repeat biopsy (tissue or liquid) after failure of treatment with a first- or second-generation EGFR-TKI and who had sufficient tumor tissue available from before treatment for genetic analysis was enrolled. The gene mutation profile of tumor tissue obtained before EGFR-TKI treatment was evaluated by next-generation sequencing with a comprehensive cancer gene panel (409 genes). The number of potentially damaging nonsynonymous mutations was predicted with PolyPhen-2 software.

      Result

      Progression-free survival during EGFR-TKI treatment did not differ significantly between patients who developed T790M-mediated resistance and those who developed T790M-independent resistance. The predicted number of damaging nonsynonymous mutations in pretreatment tumor tissue was significantly lower in patients who developed T790M-mediated resistance than in those with T790M-independent resistance (P = 0.024).

      Conclusion

      Coexisting mutations in tumor tissue before EGFR-TKI treatment may contribute to the emergence of cell clones responsible for development of T790M-dependent or T790M-independent TKI resistance in patients with EGFR-mutated NSCLC. Multiplex genomic testing of pretreatment tumor tissue may thus provide a means of identifying patients likely to develop T790M-mediated TKI resistance and therefore inform treatment selection.