A small-molecule proapoptotic agent with potential antineoplastic activity. Sepantronium bromide selectively inhibits survivin expression in tumor cells, resulting in inhibition of survivin antiapoptotic activity (via the extrinsic or intrinsic apoptotic pathways) and tumor cell apoptosis. Survivin, a member of the inhibitor of apoptosis (IAP) gene family, is expressed during embryonal development and is absent in most normal, terminally differentiated tissues; upregulated in a variety of human cancers, its expression in tumors is associated with a more aggressive phenotype, shorter survival times, and a decreased response to chemotherapy.