The present invention relates to a method of treatment of patients suffering from
cancer and harbouring mutations of EGFR in the tumour, for instance an
activating mutation of the EGFR or a
mutation responsible for resistance or the emergence of
acquired resistance to treatment with reversible EGFR and / or HER2 inhibitors or irreversible inhibitors such as CI-1033, EKB-569, HKI-272 or HKI-357, comprising administering an effective amount of the irreversible EGFR inhibitor BIBW2992 (1) 4-[(3-chloro-4-fluorophenyl)amino]-6-{[4-(N,N-dimethylamino)-1-oxo-2-buten-1-yl]amino}-7-((S)-
tetrahydrofuran-3-yloxy)-
quinazoline, to a person in need of such treatment, optionally in combination with the administration of a further chemotherapeutic agent, in combination with radiotherapy, radio-
immunotherapy and / or tumour resection by
surgery, and to the use of a BIBW 2992 (1) for preparing a pharmaceutical composition for the treatment of patients suffering from
cancer and harbouring mutations of EGFR in the tumour.