Author of

• 18975

  +

  P3.01 - Advanced NSCLC (ID 621)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23932

    +

    P3.01-073 - TPX-0005 with an EGFR Tyrosine Kinase Inhibitor (TKI) Overcomes Innate Resistance in EGFR Mutant NSCLC (ID 8956)

    09:30 - 09:30  |  Author(s): P. Cao
    • Abstract
    • Slides

    Background:
    Overexpression of several receptor tyrosine kinases (RTKs) substitutes EGFR signaling in EGFR-mutant NSCLC. The MET ligand hepatocyte growth factor (HGF) provides an alternative signaling mechanism for EGFR by inducing inter-receptor cross talk with EphA2, CUB domain-containing protein-1 (CDCP1) or AXL. SHP2, a non-receptor protein tyrosine phosphatase is central in signal transduction downstream of RTK signaling and in Src activation. We previously demonstrated that STAT3 and Src-YAP1 signaling limits EGFR TKI efficacy in EGFR-mutant NSCLC. We are now exploring the possibility of multiple RTK activation through a Src-YAP1-mediated transcriptional program. We are evaluating whether combined EGFR inhibition with TPX-0005, a novel orally available multikinase inhibitor and potent Src/FAK and JAK2 inhibitor, can be more efficient than EGFR inhibition alone in EGFR-mutant NSCLC cells.
    
    Method:
    We studied the mRNA expression levels of stromal HGF and tumor RTKs, AXL, CDCP1, MET, and EphA2, as well as SHP2, and clinical outcome in baseline samples of 64 EGFR-mutant NSCLC patients treated with first-line EGFR TKI. We combined in vitro approaches to explore whether gefitinib or osimertinib combined with TPX-0005 can abolish STAT3 and Src-YAP1 and downregulate the expression of RTKs.
    
    Result:
    High levels of AXL, CDCP1 and SHP2 mRNA expression were associated with worse outcome to EGFR TKI in 64 EGFR-mutant NSCLC patients. Median progression-free survival (PFS) was 14.5 and 23.4 months for patients with high and low AXL mRNA, respectively (p=0.0359). Median PFS was 9.1 and 20.2 months for patients with high and low CDCP1 mRNA, respectively (p=0.0179). Tumoral EPHA2 and MET or stromal HGF levels did not affect PFS. Median PFS was 11.4 and 24.1 months for patients with high and low SHP2 mRNA, respectively (p=0.0094). The combination of gefitinib/osimertinib with TPX-0005 resulted in highly synergistic suppression of cell viability and reduced colony formation in two EGFR-mutant cell lines. The combination abolished the EGFR inhibition-induced STAT3 and YAP1 phosphorylation, as confirmed by western blotting and immunofluorescence. The results of TaqMan quantitative-PCR assay revealed that gefitinib/osimertinib plus TPX-0005 reduced the mRNA levels of AXL, CDCP1 and MET, an effect that could not be obtained with EGFR inhibition alone. In vivo experiments are ongoing.
    
    Conclusion:
    AXL and CDCP1 are adverse predictive markers of PFS in EGFR-mutant NSCLC patients. STAT3 and Src-YAP1 signaling limits the efficacy EGFR TKI. Combined EGFR inhibition with TPX-0005 (currently in phase I clinical testing) is a particularly attractive strategy
    
    

    Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.