MX69 is an inhibitor of MDM2/XIAP, used for cancer treatment. In Vitro: MX69 blocks the MDM2 protein-XIAP RNA interaction, leading to MDM2 degradation. MX69 shows minimal inhibitory effect on normal human hematopoiesis in vitro and is very well tolerated in animal models. MX69-induced MDM2 downregulation results not only in inhibition of XIAP expression, but also in activation of p53, which contributes to cancer cell apoptosis in vitro. In Vivo: MX69-induced MDM2 downregulation results in activation of p53 which contributes to inhibition of cancer cell proliferation in vivo.