WZ4002, AZD9291 and CO-1686 were synthesized using previously published methods (14 (link)–16 ). Gefitinib, Afatinib, Neratinib, CL-387,785 were obtained from Selleck chemicals. The synthesis of TX2-30 is described in supplementary methods. Stock solutions of all drugs were prepared in DMSO and stored at −80°C.