Virtual Library

Start Your Search

AN Hata

Author of

  • +

    MA26 - New Therapies and Emerging Data in ALK, EGFR and ROS1 (ID 930)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Targeted Therapy
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/26/2018, 13:30 - 15:00, Room 201 BD
    • +

      MA26.03 - Activity of Osimertinib and the Selective RET Inhibitor BLU-667 in an EGFR-Mutant Patient with Acquired RET Rearrangement (ID 14731)

      13:40 - 13:45  |  Author(s): AN Hata

      • Abstract
      • Presentation
      • Slides

      The spectrum of acquired resistance (AR) to osimertinib is not yet fully characterized. We present a single-center cohort of osimertinib AR biopsies and results of a patient with RET-mediated AR treated with the investigational RET-specific TKI BLU-667 and osimertinib.
      a9ded1e5ce5d75814730bb4caaf49419 Method
      We assayed tissue via SNaPshot or Foundation One next-generation sequencing (NGS) and plasma via Guardant360 NGS under an IRB-approved protocol. In vitro studies assessed implications of RET fusions in EGFR-mutant cancers. We treated one patient with osimertinib/BLU-667 using an IRB and FDA-approved compassionate use protocol.
      4c3880bb027f159e801041b1021e88e8 Result
      41 EGFR-mutant patients with AR to osimertinib were assessed histologically and queried by tissue NGS (n=22), plasma NGS (n=9) or both (n=10). Key AR findings: SCLC transformation (2/32 tissue); EGFR C797S (5/32 tissue, 5/19 plasma, all cis with T790M); MET amplification (7/32 tissue, 3/19 plasma); BRAF rearrangement (2/32 tissue) and CCDC6-RET rearrangement (1/32 tissue, 1/19 plasma [distinct case]).
      CCDC6-RET was expressed in PC9 (EGFR del19) and MGH134 (EGFR L858R/T790M) cells, which maintained MAPK signaling and conferred resistance to osimertinib and afatinib. Inhibition of RET by BLU-667 or cabozantinib resensitized cells expressing CCDC6-RET to EGFR inhibition.
      A 60-year-old woman with EGFR del19 progressed on afatinib (T790M+), then osimertinib. Tissue biopsy at osimertinib AR showed acquired CCDC6-RET (T790-wt). She began osimertinib 80mg/BLU-667 200mg daily x2 weeks, then BLU-667 was increased to 300mg daily. Her dyspnea improved within days of initiation. Scans after 8 weeks revealed a marked response with RECIST tumor shrinkage of 78% (Figure). She experienced only grade 1 toxicities of fatigue, leukopenia, hypertension, dry mouth, and elevated transaminases.
      8eea62084ca7e541d918e823422bd82e Conclusion
      RET rearrangements are rare but recurrent in EGFR-mutant patients with AR to osimertinib. In vivo models suggest they mediate AR and this patient provides proof-of-concept that combination EGFR+RET inhibition with osimertinib/BLU-667 is a well-tolerated and effective regimen for RET-mediated AR. Further study is ongoing.



      Only 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, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      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.