Monoclonal Antibody Therapy or Biological Therapy in Treating Patients With Chronic Lymphocytic Leukemia or Multiple Myeloma in Remission After Chemotherapy

RATIONALE: Monoclonal antibodies such as rituximab can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells. Biological therapies such as interferon alfa-2b use different ways to stimulate the immune system and stop cancer cells from growing. PURPOSE: Phase II trial to study the effectiveness of rituximab or interferon alfa-2b in treating patients who have chronic lymphocytic leukemia or multiple myeloma in remission.

OBJECTIVES: I. Determine the toxicity of rituximab or interferon alfa-2b maintenance therapy in patients with chronic lymphocytic leukemia or multiple myeloma in remission after chemotherapy. II. Determine the progression free survival, failure free survival, and overall survival of these patients from time of chemotherapy discontinuation to completion of maintenance therapy. III. Compare the survival rates of these patients to similar patients treated in published studies. IV. Determine the quality of life of these patients on these regimens. OUTLINE: Patients enter one of two treatment arms: Arm I: Patients receive rituximab IV on days 1, 8, 15, and 22 for course 1, and then once a month for 11 months or until disease progression. Arm II: Patients receive subcutaneous interferon alfa-2b every other day three times per week for 12 months. Quality of life is assessed monthly during therapy. Patients are followed every 3 months for 1 year, and then annually for up to 5 years. PROJECTED ACCRUAL: A total of 60-80 patients (30-40 per disease type) will be accrued for this study.