Potent and selective γ-secretase inhibitor (IC50 = 17 nM) that displays > 50-fold selectivity over a range of aspartyl, serine and cysteine proteases. Exhibits equal potency for inhibition of Aβ40 and Aβ42 peptides (IC50 values are 48 and 67 nM respectively in human neuroblastoma cells). Also regulates CXCR4 and VEGFR2 expression through inhibition of Notch signaling in vitro.