Tositumomab and Iodine I 131 Tositumomab in Treating Patients With Chronic Lymphocytic Leukemia or Small Lymphocytic Lymphoma in First Remission

This phase II trial studies how well tositumomab and iodine I 131 tositumomab works in treating patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) that have had their first decrease in or disappearance of signs and symptoms of cancer (first remission). Monoclonal antibodies, such as tositumomab and iodine I 131 tositumomab, may block cancer growth in different ways by targeting certain cells.

PRIMARY OBJECTIVES: I. To estimate the progression-free survival at 2 years following administration of 131I-tositumomab (tositumomab and iodine I 131 tositumomab) in patients with CLL/SLL who achieve a complete remission (CR) or partial remission (PR) with prior therapy. II. To improve the response rate by administering 131I-tositumomab to patients who have achieved a PR not a CR after any prior therapy. III. To eliminate residual disease (documented by flow cytometry or polymerase chain reaction \[PCR\]) using 131I-tositumomab in patients who have achieved a CR after any prior therapy. SECONDARY OBJECTIVES: I. To evaluate the toxicities of 131I-tositumomab in 1st remission patients with previously treated CLL/SLL. OUTLINE: Patients receive tositumomab and iodine I 131 tositumomab intravenously (IV) over 90 minutes on day 0 and then again 7-14 days later over 30-60 minutes. After completion of study treatment, patients are followed up weekly for 3 months, every 3 months for 2 years, every 6 months for 3 years, and then annually thereafter.