Afatinib Is a New Therapeutic Approach in Chordoma with a Unique Ability to Target EGFR and Brachyury

Mol Cancer Ther. 2018 Mar;17(3):603-613. doi: 10.1158/1535-7163.MCT-17-0324. Epub 2017 Dec 13.


Chordomas are rare bone tumors with no approved therapy. These tumors express several activated tyrosine kinase receptors, which prompted attempts to treat patients with tyrosine kinase inhibitors. Although clinical benefit was observed in phase II clinical trials with imatinib and sorafenib, and sporadically also with EGFR inhibitors, therapies evaluated to date have shown modest activity. With the goal of identifying new drugs with immediate therapeutic potential for chordoma patients, we collected clinically approved drugs and other advanced inhibitors of MET, PDGFRβ, and EGFR tyrosine kinases, and assessed their antiproliferative activity against a panel of chordoma cell lines. Chordoma cell lines were not responsive to MET and PDGFRβ inhibitors. U-CH1 and UM-Chor1 were sensitive to all EGFR inhibitors, whereas the remaining cell lines were generally insensitive to these drugs. Afatinib was the only EGFR inhibitor with activity across the chordoma panel. We then investigated the molecular mechanisms behind the responses observed and found that the antiproliferative IC50s correlate with the unique ability of afatinib to promote degradation of EGFR and brachyury, an embryonic transcription factor considered a key driver of chordoma. Afatinib displayed potent antitumor efficacy in U-CH1, SF8894, CF322, and CF365 chordoma tumor models in vivo In the panel analyzed, high EGFR phosphorylation and low AXL and STK33 expression correlated with higher sensitivity to afatinib and deserve further investigation as potential biomarkers of response. These data support the use of afatinib in clinical trials and provide the rationale for the upcoming European phase II study on afatinib in advanced chordoma. Mol Cancer Ther; 17(3); 603-13. ©2017 AACR.

MeSH terms

  • Afatinib / therapeutic use*
  • Animals
  • Bone Neoplasms / drug therapy*
  • Bone Neoplasms / genetics
  • Bone Neoplasms / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Chordoma / drug therapy*
  • Chordoma / genetics
  • Chordoma / metabolism
  • ErbB Receptors / antagonists & inhibitors*
  • ErbB Receptors / genetics
  • ErbB Receptors / metabolism
  • Fetal Proteins / antagonists & inhibitors*
  • Fetal Proteins / genetics
  • Fetal Proteins / metabolism
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Mice, Nude
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors / therapeutic use
  • T-Box Domain Proteins / antagonists & inhibitors*
  • T-Box Domain Proteins / genetics
  • T-Box Domain Proteins / metabolism
  • Tumor Burden / drug effects
  • Tumor Burden / genetics
  • Xenograft Model Antitumor Assays*


  • Fetal Proteins
  • Protein Kinase Inhibitors
  • T-Box Domain Proteins
  • Afatinib
  • ErbB Receptors
  • Brachyury protein