WAY 316606 HCl is a selective inhibitor of sFRP-1. It bound to sFRP-2 with 10-fold weaker affinity (Kd: 1 μM). In a fluorescence polarization binding assay, WAY 316606 HCl inhibited sFRP-1 (IC50: 0.5 μM). Although sequence of sFRP-1, -2 and -5 showed high identity, WAY 316606 HCl selectively inhibited sFRP-1 against other two proteins. In the osteosarcoma U2-OS cell line used in a cell-based transient transfection and luciferase reporter assay, treatment of WAY 316606 HCl dose-dependently increased Wnt-signaling (EC50: 0.65 μM). In an ex vivo assay using neonatal murine calvarium, treatment of WAY 316606 HCl dose-dependently enhanced the osteoblast activity and stimulated bone formation up to 60% (EC50: 1 nM) [1][2].

Although WAY 316606 had good aqueous solubility and good stability, WAY 316606 HCl exerted high plasma clearance (77 mL/min/kg) in rats, which suppressed sustained exposure and limited the compound's advancement as an orally administered anabolic bone agent [1].