MRK-560 is a potent inhibitor of γ-secretase (IC50 = 0.65 nM). In vivo, MRK-560 (1-10 mg/kg) reduces diethanolamine-soluble amyloid-β (1-40) (Aβ40) levels in APP-YAC transgenic mouse brain. MRK-560 reduces brain and cerebrospinal fluid Aβ40 levels in rats (ED50s = 6 and 10 mg/kg, respectively). It also decreases brain-soluble Aβ40 and Aβ42 levels and recovers hippocampal long-term potentiation in the Tg2576 transgenic mouse model of Alzheimer''s disease.
