 Brentuximab vedotin is approved by the U.S. Food and Drug Administration FDA to be given to patients with Hodgkin Lymphoma. Mocetinostat is an experimental drug that has been given to patients with Hodgkin lymphoma in another clinical trial. When given alone, mocetinostat caused lymphoma to shrink in about 1 out of 4 patients with Hodgkin lymphoma. This is the first study that will give mocetinostat and brentuximab vedotin together. 