Lenalidomide With or Without Rituximab in Treating Patients With Progressive or Relapsed Chronic Lymphocytic Leukemia, Small Lymphocytic Lymphoma, Prolymphocytic Leukemia, or Non-Hodgkin Lymphoma Previously Treated With Donor Stem Cell Transplant

This phase II trial studies how well giving lenalidomide with or without rituximab works in treating patients with progressive or relapsed chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), prolymphocytic leukemia (PLL), or non-Hodgkin lymphoma (NHL). Biological therapies, such as lenalidomide, may stimulate the immune system in different ways and stop cancer cells from growing. Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some block the ability of cancer to grow and spread. Others find cancer cells and help kill them or carry cancer-killing substances to them. Giving lenalidomide together with or without rituximab may kill more cancer cells.