Figure 4.

Synergistic effect of pertuzumab and patritumab on heregulin‐expressing cells based on cell viability assays. A, SKBR3‐HRG and BT474‐HRG cells were incubated for 120 h with increasing concentrations of pertuzumab, patritumab, or pertuzumab with patritumab at a 1:1 ratio; cell viability was then assessed with Cell Counting Kit‐8. Each point represents the mean ± standard error of three independent experiments. B, The combination index value was calculated from the results of cell viability assays, as reported in (A), using CalcuSyn. A fractional effect‐combination index plot was then generated. The data shown are the mean of three independent experiments, with the curve showing the range of SDs