Erlotinib-d₆(hydrochloride) contains six deuterium atoms located on the methoxy group. It is intended for use as an internal standard for the quantification of erlotinib by GC- or LC-MS. Erlotinib is a tyrosine kinase inhibitor that acts on the epidermal growth factor receptor (EGFR), inhibiting EGFR-associated kinase activity (IC₅₀= 2.5 µM).^1,2This inhibits tumor growth in human head and neck carcinoma (HN5) tumor xenografts in mice with an ED₅₀value of 9 mg/kg.¹Erlotinib also suppresses cyclin-dependent kinase 2 (Cdk2) activity in breast cancer cells (IC₅₀= 4.6 µM) and JAK2 mutant JAK2^V617F(IC₅₀= 5 µM), which is associated with polycythemia vera, idiopathic myelofibrosis, and essential thrombocythemia.^3,4Formulations containing erlotinib are used to treat certain forms of cancer, including non-small cell lung cancer.^5,6

1.Ciardiello, F., and Tortora, G.A novel approach in the treatment of cancer: Targeting the epidermal growth factor receptorClin. Cancer Res.7(10)2958-2970(2001) 2.Greulich, H., Chen, T.H., Feng, W., et al.Oncogenic transformation by inhibitor-sensitive and -resistant EGFR mutantsPLoS Med.2(11)(2005) 3.Yamasaki, F., Zhang, D., Bartholomeusz, C., et al.Sensitivity of breast cancer cells to erlotinib depends on cyclin-dependent kinase 2 activityMol. Cancer Ther.6(8)2168-2177(2007) 4.Li, Z., Xu, M., Xing, S., et al.Erlotinib effectively inhibits JAK2V617F activity and polycythemia vera cell growthJ. Biol. Chem.282(6)3428-3432(2007) 5.Herbst, R.S., and Bunn, P.A., Jr.Targeting the epidermal growth factor receptor in non-small cell lung cancerClin. Cancer Res.9(16)5813-5824(2003) 6.Gerber, D.E.EGFR inhibition in the treatment of non-small cell lung cancerDrug Dev. Res.69(6)359-372(2008)