The hydrochloride salt of enzastaurin, a synthetic macrocyclic bisindolemaleimide with potential antineoplastic activity. Binding to the ATP-binding site, enzastaurin selectively inhibits protein kinase C beta, an enzyme involved in the induction of vascular endothelial growth factor (VEGF)-stimulated neo-angiogenesis. This agent may decrease tumor blood supply and so tumor burden. Check for active clinical trials using this agent. (NCI Thesaurus)