The protease γ-secretase plays a pivotal role in the synthesis of pathogenic amyloid-β in Alzheimer's disease (AD). Here, we report a further extension to a series of cyclohexyl sulfone-based γ-secretase inhibitors which has allowed the preparation of highly potent compounds which also demonstrate robust Aβ (40) lowering in vivo (eg, compound 32, MED 1mg/kg po in APP-YAC mice).