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  MINI 08 - Prognostic/Predictive Biomarkers (ID 106)

  • Event: WCLC 2015
  • Type: Mini Oral
  • Track: Biology, Pathology, and Molecular Testing
  • Presentations: 1
  • Moderators:T.E. Stinchcombe, N. Pavlakis
  • Coordinates: 9/07/2015, 16:45 - 18:15, Mile High Ballroom 4a-4f

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    MINI08.04 - VeriStrat® and Epidermal Growth Factor Receptor Mutation Status in a Phase 1b/2 Study of Cabozantinib +/- Erlotinib in Non-Small Cell Lung Cancer (ID 552)

    17:10 - 17:15  |  Author(s): D.S. Subramaniam
    • Abstract
    • Presentation
    • Slides

    Background:
    VeriStrat is a blood-based multivariate proteomic test that predicts response to second line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) therapy in non-small cell lung cancer (NSCLC). We report a retrospective blinded analysis of VeriStrat classification in plasma samples from a phase 1b/2 trial of cabozantinib (C) +/- erlotinib (E) in metastatic NSCLC patients who had all progressed after benefiting from EGFR TKI therapy. Cabozantinib inhibits the MET/hepatocyte growth factor (HGF) pathway, and VeriStrat may be a surrogate marker for this pathway.
    
    Methods:
    Patients enrolled into phase 1b (1A:60 mg C+150 mg E, 2A:60 mg C+100 mg E, 3A:100 mg C+100 mg E, 4A:100 mg C+50 mg E, 2B:40 mg C+150 mg E) and phase 2 (Arm A:100 mg C, Arm B:100 mg C+50 mg E). EGFR mutation (EGFRm) status was tested on archival tissue and/or plasma when available. The primary objective was to determine if pre-treatment VeriStrat (VS) classification, good or poor, was prognostic for patients treated with cabozantinib +/- erlotinib. Kaplan-Meier method and log-rank test was used to compare progression-free survival (PFS) of VS-good v. VS-poor patients. Outcomes were stratified by EGFRm status (mutated v. wild type WT/unknown UNK).
    
    Results:
    Of 79 evaluable patients, 71 were classified as VS-good and 8 as VS-poor. 55.7% had an activating EGFRm (majority exon 19 del/exon 21 L858R) and 12.7% had UNK EGFRm status. There were no significant differences in patient characteristics between VeriStrat-groups. VS-good patients had a statistically improved PFS: VS-good 3.7 mo. (95% CI 3.5-5.4) v. VS-poor 1.9 mo. (95% CI 1.1-3.4), p=0.014. This was still true after excluding 14 patients who had received cabozantinib alone (p=0.005). There was no difference in PFS for VS-good patients when stratified by EGFRm status. There was also no difference in PFS for VS-poor patients with WT/UNK EGFR v. VS-good patients irrespective of EGFRm status. However, VS-poor patients with WT/UNK EGFR had improved PFS compared to VS-poor patients with an EGFRm (3.1 mo. v. 1.6 mo., HR 0.15, 95% CI 0.03-0.68).
    
    Conclusion:
    VeriStrat is a strong prognostic marker in this study. This study suggests cabozantinib neutralized the worse prognosis of VS-poor patients with WT/UNK EGFR. Given the heterogeneity of treatment dosing, the small number of VS-poor patients, and a high proportion of unknown EGFRm (including T790M) status, this analysis should be considered exploratory.
    
    

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