Effect of AZD9291 on EGFR phosphorylation in vitro. A, In comparison to early generation TKIs, AZD9291 inhibits EGFR phosphorylation across cell lines harboring sensitising (PC-9, H3255, H1650) or T790M resistance (H1975, PC-9VanR) mutations, whilst having less activity against wild-type EGFR phosphorylation (LOVO, A431, H2073). Apparent geomean IC50 (nM) values quantified in cell extracts after 2 h compound treatment using a phospho-EGFR ELISA from at least two separate experiments (expressed with 95% confidence intervals where n>3, or individual IC50 values where n=2). B, AZD9291 inhibits EGFR phosphorylation and downstream signaling pathways across representative mutant EGFR lines (PC-9, H1975, H1650, H3255), whilst having less activity against EGFR phosphorylation in the LOVO wild-type EGFR cell line compared to early generation TKIs, after 6 h treatment. The data is representative of at least two separate experiments.