Research ArticleCancer

Neratinib is effective in breast tumors bearing both amplification and mutation of ERBB2 (HER2)

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Sci. Signal.  09 Oct 2018:
Vol. 11, Issue 551, eaat9773
DOI: 10.1126/scisignal.aat9773
  • Fig. 1 Coexistence of ERBB2 amplification and mutations in metastatic breast cancer.

    (A) Schematic representation of the detection of HER2 mutations in HER2-positive breast cancer patients treated with anti-HER2 therapy for the indicated time. “HER2 3+” refers to tumors that were highly positive for HER2 staining by immunohistochemistry (IHC). (B) OncoPrint software-generated genomic alterations heatmap of the ERBB2-amplified patients available in the MSK database. (C) Graph indicating the proportion of primary or metastatic patients with tumors bearing concomitant mutation and amplification of ERBB2. (D) Kaplen-Meyer curves showing the progression-free survival of the MSK cohort of HER2-positive patients treated with the standard-of-care trastuzumab/pertuzumab/paclitaxel combination (THP). Displayed inset is the hazard ratio (HR) with 95% confidence interval (95% CI) of patients with ERBB2-mutant/amplified (coincident) tumors versus ERBB2-amplified–only tumors.

  • Fig. 2 HER2 L755S mutation confers resistance to lapatinib.

    (A to D) Western blot analysis of the indicated total and phosphorylated (p) proteins and phospho-tyrosine (pTYR) in whole-cell extracts (A and C) and cell viability by CellTiter-Glo (CTG) assay (B and D) from Sk-Br-3 cells and BT474 cells expressing empty vector, WT HER2, or HER2 L755S and cultured in various concentrations of lapatinib for 4 hours. Data are means ± SD from three independent experiments. P value obtained by two-tailed Student’s t test.

  • Fig. 3 HER2 L755S mutation induces resistance to HER2-targeted therapy.

    (A and B) Clonogenic growth assays performed by crystal violet staining on Sk-Br-3 (A) and BT474 (B) cells expressing empty vector, WT, or mutant (L755S) HER2 constructs and cultured with trastuzumab (20 μg/ml), lapatinib (500 nM), or the combination, as indicated, for 10 days. Results from treated cultures were quantified relative to nontreated cells. Data are means ± SEM from three independent experiments. **P < 0.05 by two-tailed Student’s t test. NT, non-treated.

  • Fig. 4 Activity of neratinib against breast cancer cells carrying both the amplification and mutation of HER2.

    (A to D) Western blot analysis of the indicated total and phosphorylated (p) proteins and phospho-tyrosine (pTYR) in whole-cell extracts (A and C) and cell viability by CTG assay (B and D) from Sk-Br-3 cells and BT474 cells expressing empty vector, WT HER2, or HER2 L755S and cultured in various concentrations of neratinib for 4 hours. Data are means ± SD from three independent experiments. P value obtained by two-tailed Student’s t test.

  • Fig. 5 In vivo efficacy of neratinib against HER2-amplified and mutant PDXs.

    Growth of PDXs containing coincident ERBB2 amplification and HER2 D769Y mutation in mice treated with vehicle (control), trastuzumab (10 mg/kg intraperitoneal, twice weekly), lapatinib (100 mg/kg daily), or neratinib (40 mg/kg daily). Data are means ± SEM from eight mice each condition. P < 0.001 by two-tailed Student’s t test

  • Table 1 Clinical benefit of neratinib treatment in HER2-amplified/mutant breast cancer patients.

    SD, stable disease [tumor volume (TV) changing within the +20% or −30% range compared to baseline pretreatment]; PR, partial response (TV decreasing more than 30% compared to baseline pretreatment).

    PatientHER2
    mutation
    ERBB2 gene
    copies
    Best response
    to neratinib
    Time on
    treatment (days)
    AL755S9*SD141
    BY772_A775dup6*SD122
    CV777L11*PR166
    2L313I25PR300
    3R456C22SD270
    4D769Y6SD180

    *Response of a small cohort of patient with HER2-amplified/mutant tumors from the MSK-IMPACT database performed at the respective hospital as part of routine diagnosis and monitoring.

    †Response of a small cohort of patient with HER2-amplified/mutant tumors by fluorescence in situ hybridization (FISH) performed at the respective hospital as part of routine diagnosis and monitoring.

    Supplementary Materials

    • This PDF file includes:

      • Text S1. Clinical case details.
      • Fig. S1. Prevalence of coincident HER2 amplification and mutation in the MSKCC breast cancer cohort.

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