Brain-penetrant, orally active, highly potent and selective gamma-secretase inhibitor with CNS Aβ40-lowering efficacy in mice and rats in vivo.
MRK-560 is a brain-penetrant, orally active, highly potent and selective gamma-secretase inhibitor (GSI; IC50 = 0.65 nM by SH-SY5Y cellular γ-secretase substrate A4CTF breakdown assay) with little inhibitory potency against a panel of 171 enzymes/receptors. MRK-560 blocks Aβ40 & Aβ42 production with similar potency in SH-SY5Y cultures (IC50 <0.5 nM) and lowers CNS Aβ40 in rats (brain & SCF ED50 in 8h = 6 & 10 mg/kg po.) and APP-YAC mice (brain ED50 in 4h <3 mg/kg po.) in vivo