Bortezomib, Rituximab, Cyclophosphamide, and Prednisone in Treating Patients With Relapsed or Refractory Indolent Non-Hodgkin's Lymphoma

RATIONALE: Bortezomib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as cyclophosphamide and prednisone, work in different ways to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some block the ability of cancer cells to grow and spread. Others find cancer cells and help kill them or carry cancer-killing substances to them. Giving bortezomib together with cyclophosphamide, prednisone, and rituximab may be an effective treatment for non-Hodgkin's lymphoma. PURPOSE: This randomized phase I/II trial is studying the side effects and best dose of bortezomib when given together with cyclophosphamide, prednisone, and rituximab and to see how well it works in treating patients with relapsed or refractory indolent B-cell non-Hodgkin's lymphoma.