Elesclomol (also known as STA-4783), originally identified in a cell-based phenotypic screen for proapoptotic activity, is a novel small-molecule that potently induces apoptosis of cancer cells through the rapid generation of reactive oxygen species (ROS) and the induction of unmanageable levels of oxidative stress. Elesclomol exhibits autitumor activity against a broad spectrum of types of cancer cell in human tumor xengograft models due to its excessive ROS production and elevated levels of oxidative stress leading to the death of cancer cells. Elesclomol is currently being studies as a novel cancer therapeutic, in which it has demonstrated ability to prolong progression-free survival in study subjects. Elesclomol induces oxidative stress by provoking a buildup of reactive oxygen species within cancer cells. Elesclomol requires a redox active metal ion to function; the Cu(II) complex is 34 times more potent than the Ni(II) complex and 1040-fold more potent than the Pt(II) complex.