Q-VD-OPh is an irreversible pan-caspase inhibitor with potent antiapoptotic properties; inhibits caspase 7 with an IC₅₀ of 48 nM and 25-400 nM for other caspases including caspase 1, 3, 8, 9, 10, and 12. Q-VD-OPh can inhibits HIV infection. Q-VD-OPh is able to cross the blood-brain barrier. IC50 & Target: IC50: 48 nM (caspase 7), 25-400 nM (caspase 1, 3, 8, 9, 10, and 12)^[1] In Vitro: Q-VD-OPh is a potent inhibitor of caspase-7 with an IC₅₀ of 48 nM utilizing a cell-free assay consisting of human recombinant caspase-7, Q-VD-OPh, and the substrate AMC-DEVD-pNa^[1]. Q-VD-OPh fully inhibits caspase-3 and -7 activity at 0.05 μM. Caspase-8 is also inhibited at low Q-VD-OPh concentrations. The cleavage of PARP-1 is fully prevented at 10 μM Q-VD-OPh. DNA fragmentation and disruption of the cell membrane functionality are both prevented at 2 μM Q-VD-OPh^[2]. Q-VD-OPh is significantly more effective in preventing apoptosis than the widely used inhibitors, ZVAD-fmk and Boc-D-fmk, and is also equally effective in preventing apoptosis mediated by the three major apoptotic pathways, caspase 9/3, caspase 8/10, and caspase12. Q-VD-OPh is not toxic to cells even at extremely high concentrations^[3]. QVD is also able to increase the expression of differentiation markers in acute myeloid leukemia (AmL) blasts. QVD alone or combined with VDDs increases differentiation and HPK1-cJun signaling in AmL cell context-dependent manner^[4]. In Vivo: Chronic treatment with Q-VD-OPh prevents caspase-7 activation and limits the pathological changes associated with tau, including caspase cleavage. Q-VD-OPh could be a potential therapeutic compound for the treatment of Alzheimer's disease^[1].