SM-433, a Smac mimetic, function as inhibitor of inhibitor of apoptosis proteins (IAPs). SM-433 exhibits strong binding affinity XIAP BIR3 protein with an IC50<1 μM (patent WO2008128171A2).In Vitro: SM-433 exhibits strong inhibitory activity against MDA-MB -2131 human breast cancer cells and SK-OV-3 ovarian cancer cells (IC50s<10 μM, respectively).