Resistance to avapritinib in pdgfra-driven gist is caused by secondary mutations in the pdgfra kinase domain

Susanne Grunewald, Lillian R. Klug, Thomas Mühlenberg, Jonas Lategahn, Johanna Falkenhorst, Ajia Town, Christiane Ehrt, Eva Wardelmann, Wolfgang Hartmann, Hans Ulrich Schildhaus, Juergen Treckmann, Jonathan A. Fletcher, Sascha Jung, Paul Czodrowski, Stephen Miller, Oleg Schmidt-Kittler, Daniel Rauh, Michael C. Heinrich, Sebastian Bauer

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Gastrointestinal stromal tumors (GIST) harboring activating mutations of PDGFRA respond to imatinib, with the notable exception of the most common mutation, D842V. Avapritinib is a novel, potent KIT/PDGFRA inhibitor with substantial clinical activity in patients with the D842V genotype. To date, only a minority of PDGFRA-mutant patients treated with avapri-tinib have developed secondary resistance. Tumor and plasma biopsies in 6 of 7 patients with PDGFRA primary mutations who progressed on avapritinib or imatinib had secondary resistance mutations within PDGFRA exons 13, 14, and 15 that interfere with avapritinib binding. Secondary PDGFRA mutations causing V658A, N659K, Y676C, and G680R substitutions were found in 2 or more patients each, representing recurrent mechanisms of PDGFRA GIST drug resistance. Notably, most PDGFRA-mutant GISTs refractory to avapritinib remain dependent on the PDGFRA oncogenic signal. Inhibitors that target PDGFRA protein stability or inhibition of PDGFRA-dependent signaling pathways may overcome avapritinib resistance.

Original languageEnglish (US)
Pages (from-to)108-125
Number of pages18
JournalCancer discovery
Issue number1
StatePublished - Jan 2021

ASJC Scopus subject areas

  • Oncology


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