A bicyclic depsipeptide antibiotic isolated from the bacterium Chromobacterium violaceum with antineoplastic activity. After intracellular activation, romidepsin binds to and inhibits histone deacetylase (HDAC), resulting in alterations in gene expression and the induction of cell differentiation, cell cycle arrest, and apoptosis. This agent also inhibits hypoxia-induced angiogenesis and depletes several heat shock protein 90 (Hsp90)-dependent oncoproteins. or A drug used to treat cutaneous T-cell lymphoma in patients who have been treated with other anticancer drugs. It is also being studied in the treatment of other types of cancer. Romidepsin blocks certain enzymes, which may help kill cancer cells. It is a type of depsipeptide and a type of histone deacetylase inhibitor. Also called FR901228 and Istodax.