A novel, broad-spectrum hydroxamic acid-based inhibitor of histone deacetylase (HDAC) with potential antineoplastic activity. Abexinostat inhibits several isoforms of HDAC, resulting in an accumulation of highly acetylated histones, followed by the induction of chromatin remodeling; the selective transcription of tumor suppressor genes; and the tumor suppressor protein-mediated inhibition of tumor cell division and induction of tumor cell apoptosis. HDAC, upregulated in many tumor types, is an an enzyme that is responsible for the deacetylation of chromatin histone proteins.