Participants receive three infusions of Romidepsin administered through an intravenous line over 4 hours on days 1, 3 and 5 of a 21-day treatment cycle. The intravenous line is a catheter (plastic tube) placed in a vein and may be a peripheral line, inserted in a vein in the arm, or a central line, in which the tube is placed under the skin of the chest or neck into a major vein. Patients are hospitalized for the first 6 days of the first cycle to monitor heart rate. Those who tolerate the treatment well may continue as an outpatient.