...at position 854 (T854A), was identified in one patient with a drug-sensitive EGFR L858R-mutant lung adenocarcinoma after long-term treatment with tyrosine kinase inhibitors...Surrogate kinase assays show that the EGFR T854A mutation abrogates the inhibition of tyrosine phosphorylation by erlotinib...Such resistance seems to be overcome by a new irreversible dual EGFR/HER2 inhibitor, BIBW 2992...Furthermore, BIBW 2992 was able to overcome the resistance conferred by both T790M and T854A.