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. 2021 Sep 20;12(1):204–219. doi: 10.1158/2159-8290.CD-21-0072

Figure 6.

Figure 6. p110a-Mutant degrading inhibitors provide more benefit in HER2-positive versus HER2-negative p110a-mutant cancers. A, Mechanistic model of drug-induced p110a degradation in HER2-positive and HER2-negative PIK3CA-mutant cells. B, Growth response of seven HER2-amplified breast cancer cells with different PIK3CA status to treatment with GDC-0077 at 0.37 μmol/L (blue), lapatinib at 0.37 μmol/L (green), or the combination (dark purple). The y-axis shows normalized growth inhibition (GR value); HSA stands for excess over single agent. C, Tumor growth curve from KPL-4 (HER2+, PIK3CA H1047R) xenograft treated with vehicle, taselisib, trastuzumab plus pertuzumab, or the indicated drug combination. D, Tumor growth curve from KPL-4 (HER2+, PIK3CA H1047R) xenograft treated with vehicle, GDC-0077, TDM-1, or the indicated drug combination.

p110a-Mutant degrading inhibitors provide more benefit in HER2-positive versus HER2-negative p110a-mutant cancers. A, Mechanistic model of drug-induced p110a degradation in HER2-positive and HER2-negative PIK3CA-mutant cells. B, Growth response of seven HER2-amplified breast cancer cells with different PIK3CA status to treatment with GDC-0077 at 0.37 μmol/L (blue), lapatinib at 0.37 μmol/L (green), or the combination (dark purple). The y-axis shows normalized growth inhibition (GR value); HSA stands for excess over single agent. C, Tumor growth curve from KPL-4 (HER2+, PIK3CA H1047R) xenograft treated with vehicle, taselisib, trastuzumab plus pertuzumab, or the indicated drug combination. D, Tumor growth curve from KPL-4 (HER2+, PIK3CA H1047R) xenograft treated with vehicle, GDC-0077, TDM-1, or the indicated drug combination.