An Acquired HER2T798I Gatekeeper Mutation Induces Resistance to Neratinib in a Patient with HER2 Mutant-Driven Breast Cancer
Ariella B Hanker, Monica Red Brewer, Jonathan H Sheehan, James P Koch, Gregory R Sliwoski, Rebecca Nagy, Richard Lanman, Michael F Berger, David M Hyman, David B Solit, Jie He, Vincent Miller, Richard E Cutler Jr, Alshad S Lalani, Darren Cross, Christine M Lovly, Jens Meiler, Carlos L Arteaga, Ariella B Hanker, Monica Red Brewer, Jonathan H Sheehan, James P Koch, Gregory R Sliwoski, Rebecca Nagy, Richard Lanman, Michael F Berger, David M Hyman, David B Solit, Jie He, Vincent Miller, Richard E Cutler Jr, Alshad S Lalani, Darren Cross, Christine M Lovly, Jens Meiler, Carlos L Arteaga
Abstract
We report a HER2T798I gatekeeper mutation in a patient with HER2L869R-mutant breast cancer with acquired resistance to neratinib. Laboratory studies suggested that HER2L869R is a neratinib-sensitive, gain-of-function mutation that upon dimerization with mutant HER3E928G, also present in the breast cancer, amplifies HER2 signaling. The patient was treated with neratinib and exhibited a sustained partial response. Upon clinical progression, HER2T798I was detected in plasma tumor cell-free DNA. Structural modeling of this acquired mutation suggested that the increased bulk of isoleucine in HER2T798I reduces neratinib binding. Neratinib blocked HER2-mediated signaling and growth in cells expressing HER2L869R but not HER2L869R/T798I In contrast, afatinib and the osimertinib metabolite AZ5104 strongly suppressed HER2L869R/T798I-induced signaling and cell growth. Acquisition of HER2T798I upon development of resistance to neratinib in a breast cancer with an initial activating HER2 mutation suggests HER2L869R is a driver mutation. HER2T798I-mediated neratinib resistance may be overcome by other irreversible HER2 inhibitors like afatinib.Significance: We found an acquired HER2 gatekeeper mutation in a patient with HER2-mutant breast cancer upon clinical progression on neratinib. We speculate that HER2T798I may arise as a secondary mutation following response to effective HER2 tyrosine kinase inhibitors (TKI) in other cancers with HER2-activating mutations. This resistance may be overcome by other irreversible HER2 TKIs, such as afatinib. Cancer Discov; 7(6); 575-85. ©2017 AACR.This article is highlighted in the In This Issue feature, p. 539.
Trial registration: ClinicalTrials.gov NCT01953926.
Conflict of interest statement
Disclosure of potential conflicts of interest: R.N. and R.L. are employees of Guardant Health. J.H. and V.M. are employees of Foundation Medicine. R.E.C. and A.S.L. are employees of Puma Biotechnology. D.C. is an employee of AstraZeneca. Other authors declare no conflicts of interest.
©2017 American Association for Cancer Research.
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Source: PubMed