Afatinib (BIBW 2992) is an irreversible inhibitor of the EGFR family (EGFR-wt, EGFR-L858R, EGFR-L858R/T790M, and HER2) with IC50s of 0.5 nM, 0.4 nM, 10 nM, and 14 nM, respectively.

EGFR (L858R):0.4 nM, HER2:14 nM, EGFR (L858R/T790M):10 nM, EGFR:0.5 nM

METHODS: NSCLC cells NCI-H1975, NCI-H1781, HCC827 and A549 were treated with Afatinib (0.0001-10 µM) for 72 h. Cell viability was measured by MTS assay.
RESULTS: Afatinib inhibited the survival of tumor cell lines harboring wild-type (H1666) or L858R/T790M (NCI-H1975) EGFR. Afatinib is also effective against NSCLC cell lines expressing HER2 776insV (NCI-H1781) or EGFR E746_A750del (HCC827), but is inactive against A549 cells expressing wild-type EGFR and HER2 but also harboring the oncogenic Kras G12S point mutation. [1]
METHODS: BEAS-2B cells overexpressing wild-type or mutant HER2 were treated with Afatinib (0.1 µM) for 6 h, and target protein expression levels were measured by Western Blot.
RESULTS: Afatinib treatment inhibited the phosphorylation of HER2, EGFR and AKT. [2]

METHODS: To assay antitumor activity in vivo, Afatinib (20 mg/kg, 1.8% HP-beta-CD + 5% acetic acid (10%) + aqueous Natrosol (0.5%)) was administered by gavage to NMRI-nu/nu mice bearing A431 xenografts once daily for 25 days.
RESULTS: Afatinib resulted in significant tumor regression with a cumulative treatment/control tumor volume ratio (T/C ratio) of 2% and downregulation of EGFR and AKT phosphorylation. [1]