Thus, Afatinib is an irreversible EGFR family inhibitor. The IC50s are 0.5 nM, 0.4 nM, 10 nM, and 14 nM for EGFR wt, EGFR L858R, EGFR L858R/T790M, and HER2, respectively.

The classic cytogenetic abnormality associated with this disease is a reciprocal translocation of the long arms of chromosomes 11 and 22, t(11;22), which creates a chimeric gene product of unknown function with components from the fli-1 gene on chromosome 11 and ews on 22.