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Anastasios Dimou



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    MA02 - Improving Outcomes for Patients with Lung Cancer (ID 895)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 10:30 - 12:00, Room 201 BD
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      MA02.01 - ROS1 Gene Rearrangements Are Associated with an Exaggerated Risk of Peri-Diagnosis Thromboembolic Events (ID 12442)

      10:30 - 10:35  |  Author(s): Anastasios Dimou

      • Abstract
      • Presentation
      • Slides

      Background

      Based on clinical observation, we hypothesized that ROS1 gene-rearranged non-small cell lung cancer (ROS1+ NSCLC) has a higher than expected thromboembolic event (TEE) rate. A multicenter, retrospective cohort study of TEE in advanced ROS1+, KRAS+, ALK+ and EGFR+ NSCLC was conducted.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Venous (DVT / PE) and arterial (MI/TIA/CVA) TEE within +/- 365 days of diagnosis of ROS1+, KRAS+, ALK+ or EGFR+ advanced NSCLC at 4 academic centers in USA and China from October 2002 to January 2018 were captured. The primary endpoint was the incidence of TEE in ROS1+ compared to KRAS+ NSCLC as a control group within +/- 90 days of diagnosis. Secondary endpoints compared TEE incidence between ROS1+ and ALK+, and ROS1+ and EGFR+. Fine-Gray Model was used to detect differences in TEE incidence while accounting for death as a competing risk.

      4c3880bb027f159e801041b1021e88e8 Result

      105 ROS1+, 101 ALK+, 112 EGFR+, and 114 KRAS+ NSCLC patients were enrolled. Incidence rate of TEE within +/- 90 days of diagnosis was 30.5% (32/105), 12.9% (13/101), 7.1% (8/112), and 12.3% (14/114) in the respective molecular cohorts. Compared to the ROS1+ cohort, the risk of TEE was significantly lower in the three other cohorts (KRAS+ HR 0.334, 95% CI: 0.18-0.62, p=0.001; ALK+ HR 0.357, 95% CI: 0.188-0.68, p=0.002; EGFR+ HR 0.193, 95% CI: 0.089-0.421, p<0.001) (Figure 1). First event TEEs were venous as opposed to arterial in 59.5% (22/37) ROS1+, 87.1% (27/31) ALK+, 80.6% (25/31) EGFR+, and 80% (16/20) KRAS+ cases. The median time (Interquartile Range) to TEE from the time of diagnosis for ROS1+/ALK+/EGFR+/ KRAS+ was 0 days (-6.75 to 7.0), 0 days (-20.0 to 35.0), 0.50 days (-43.7 to 21.3), and 13 days (0.49 to 32.0), respectively.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Among common molecular subtypes of NSCLC, ROS1+ oncogene is associated with a significantly higher risk of developing TEE within +/- 90 days of advanced NSCLC diagnosis.

      figure 1 ros1 90 day.tif

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    OA12 - Novel Therapies in MET, RET and BRAF (ID 921)

    • Event: WCLC 2018
    • Type: Oral Abstract Session
    • Track: Targeted Therapy
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 15:15 - 16:45, Room 106
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      OA12.06 - Mutational Landscape of BRAF V600E Positive Lung Cancer Patients Following BRAF Directed Therapy Failure (ID 13540)

      16:10 - 16:20  |  Presenting Author(s): Anastasios Dimou

      • Abstract
      • Presentation
      • Slides

      Background

      BRAF V600E mutation is identified as molecular drivers in 1-2% of lung adenocarcinomas and predicts response to combination BRAF and MEK inhibitors. Little is known about molecular mechanisms of acquired resistance to these therapies for lung cancer patients with BRAF V600E mutations, partially due to a lack of representative cancer models.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      We identified patients with BRAF V600E mutated lung cancer who were progressing after initial response to a BRAF/MEK inhibitor combination in 5 academic institutions in the US. Potential molecular mechanisms of resistance were explored by comparing pre- and post-therapy results from comprehensive tissue and/or the Guardant360 and FoundationACT plasma-based next generation sequencing assays.

      4c3880bb027f159e801041b1021e88e8 Result

      We identified 6 patients. Prior to treatment with a BRAF/MEK inhibitor combination, four patients had received at least one line of chemotherapy and immune checkpoint inhibitor monotherapy, one had received chemotherapy only and one was treatment naïve. Five patients received dabrafenib/trametinib and one vemurafenib/cobimetinib combination. All 6 patients achieved a partial response. Progression free survival (PFS) ranged from 3 to 15 months (median 9.5 months). At the time of progression, all patients had the BRAF V600E mutation re-identified in their samples. Additionally, there was one patient with a new AKT1 E17K and a new KRAS G12A mutation, one patient with a new VHL R167Q mutation and one patient with a new TP53 splice site indel mutation at the time of progression. Another two patients had AKT1 E17K mutations that were present prior to BRAF/MEK inhibitor therapy. They both had oligoprogression, one in lymph nodes and one in the brain after 5.2 and 3 months, respectively; both continued on dabrafenib and trametinib combination therapy after radiation treatment to the progressing sites. Interestingly, co-occurrence of AKT1 E17K and BRAF V600E mutations is rare in the TCGA data, but was identified in three of six patients in our case series. Finally, we have established a BRAF V600E positive lung adenocarcinoma cell line from a TKI naïve patient for further functional studies of drug resistance.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Comprehensive molecular testing can identify potential resistance mechanisms following progression of BRAF V600E positive lung cancer to TKI therapy. AKT1 mutations were common as co-alterations in BRAF V600E mutated lung adenocarcinoma before and after targeted therapy and may contribute to drug resistance. The development of patient-derived cell line models may assist in the identification and validation of drug resistance mechanisms, and may help devise strategies to overcome drug resistance.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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