WAY-204688 is an estrogen receptor ( ER-α ) selective, orally active inhibitor of NF-κB transcriptional activity with an IC 50 of 122 ± 30 nM for NF-κB-luciferase (NF-κB-luc) in HAECT-1 cells. In Vitro WAY-204688 is ER-dependenrt (activity seen only when hER is coexpressed with NF-κB-luciferase in human aortic endothelial cell lines (HAECT-1) cells). The interaction of WAY-204688 with ERα and ERβ is examined in vitro. WAY-204688 displaces [ 3 H]E2 from the ERα ligand binding domain protein (LBD) with IC 50 =2.43 μM and from the ERβ ligand binding domain protein (LBD) with IC 50 =1.5 μM. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo WAY-204688 (5 mg/kg per day, po daily for 5 weeks) is evaluated in vivo for the ability to inhibit four proinflammatory genes (MHC, invariant chain (MHI), VCAM-1, RANTES, and TNF-α). The effect of WAY-204688 on induction of the gene products and on uterine wet weight is compared to that of 17α-ethinyl 17β-estradiol (EE at 10 μg/kg per day) in the same paradigm. Further characterization of WAY-204688 is carried out in several preclinical models of inflammatory disease. In the Lewis rat adjuvant-induced arthritis model (AIA), WAY-204688 is active at a dose of 0.3 mg/kg per day, po . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid IC50& Target:NF-κB-luc 122 nM (IC 50 , in HAECT-1 cell) NF-κB