Sorafenib N-oxide

Sorafenib N-oxide is an active metabolite of sorafenib , an inhibitor of Raf-1, B-RAF, and receptor tyrosine kinases. Sorafenib N-oxide inhibits FLT3 that contains the internal tandem duplication mutation (FLT3-ITD; Kd = 70 nM) and inhibits proliferation of MV4-11 acute myeloid leukemia (AML) cells expressing FLT3-ITD (IC50 = 25.8 nM). It is selective for AML cell lines containing FLT3-ITD over lines containing wild-type FLT3 (IC50s = 3.9-13.3 µM). Sorafenib N-oxide is also a linear-mixed inhibitor of the cytochrome P450 (CYP) isoform CYP3A4 (Ki = 15 µM in human liver microsomes).