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. or A substance being studied in the treatment of certain types of cancer, including non-Hodgkin lymphoma, breast, colon, lung, ovarian, and prostate. Enzastaurin hydrochloride blocks certain cell signaling pathways, and may prevent the growth of new blood vessels that tumors need to grow. It is a type of serine threonine kinase inhibitor and a type of antiangiogenesis agent. Also called enzastaurin and LY317615.