NCIt definition : An orally bioavailable anilino-quinazoline derivative and inhibitor of the receptor
tyrosine kinase (RTK) epidermal growth factor receptor (ErbB; EGFR) family, with antineoplastic
activity. Upon administration, afatinib selectively and irreversibly binds to and
inhibits the epidermal growth factor receptors 1 (ErbB1; EGFR), 2 (ErbB2; HER2), and
4 (ErbB4; HER4), and certain EGFR mutants, including those caused by EGFR exon 19
deletion mutations or exon 21 (L858R) mutations. This may result in the inhibition
of tumor growth and angiogenesis in tumor cells overexpressing these RTKs. Additionally,
afatinib inhibits the EGFR T790M gatekeeper mutation which is resistant to treatment
with first-generation EGFR inhibitors. EGFR, HER2 and HER4 are RTKs that belong to
the EGFR superfamily; they play major roles in both tumor cell proliferation and tumor
vascularization and are overexpressed in many cancer cell types.;