Steady-state efficacy of SPI-1865 in wild-type mice. SPI-1865 was orally dosed twice daily (BID) for six days in male CD-1 mice. Tissues were harvested 6 hrs after the final dose. The levels of compound, β-amyloid (Aβ)38, Aβ40, Aβ42 were measured in brain. Compound levels were also measured in plasma. (A) Aβ levels are graphed as % of vehicle control. *P-value < 0.01 based on analysis of variance (Dunnett's test). The percent Aβ42 lowering for each of the animals in this study was then plotted against the concentrations of SPI-1865 in the plasma (B) and brain (C). A best-fit line was plotted using GraphPad and the ED50s were extrapolated and shown under each graph with the IC50 of SPI-1865 in cells.