n-desmethyl-4-hydroxytamoxifen

SIM010603 is a structurally novel, oral, multi-targeted receptor tyrosine kinase inhibitor. SIM010603 inhibited stem cell factor receptor (Kit), vascular endothelial growth factor receptor-2 (VEGFR-2), platelet-derived growth factor receptor-β (PDGFR-β), glial cell line-derived neurotrophic factor receptor (Rearranged during Transfection; RET), and Fms-like tyrosine kinase-3 (FLT3) with IC(50) values between 5.0 and 68.1 nmol/l. SIM010603 inhibited the phosphorylation of PDGFR-β and VEGFR-2. Moreover, SIM010603 inhibited endothelial cell proliferation, endothelial cells chemotaxis, and corneal angiogenesis.

(E/Z)-Endoxifen ((E/Z)-Endoxifen) is an active metabolite of tamoxifen produced by the sequential action of cytochrome P450 (CYP) isoforms, including CYP2D6. It is a strong anti-estrogen, as it has an approximately 100-fold greater affinity for estrogen receptors than tamoxifen. As the efficient conversion of tamoxifen to endoxifen depends on CYP2D6, polymorphisms in this CYP isoform can impact the effectiveness of TMX treatment.

Endoxifen, also known as N-desmethyl-4-hydroxytamoxifen, is a chemical that is under development for estrogen receptor-positive breast cancer. It is also being evaluated as an antipsychotic for treatment of mania and other psychotic disorders. Endoxifen is a nonsteroidal selective estrogen receptor modulator (SERM) of the triphenylethylene group. It is an active metabolite of tamoxifen and has been found to be effective in patients that have failed previous hormonal therapies (tamoxifen, aromatase inhibitors, and fulvestrant). The prodrug tamoxifen is metabolized by the CYP2D6 enzyme to produce afimoxifene (4-hydroxytamoxifen) and endoxifen.