90Yttrium Ibritumomab Tiuxetan (Zevalin) for the Treatment of Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: A Report of 5 Cases.

Radioimmunotherapy (RIT) with radio-labeled monoclonal antibodies to CD20 produces a high response rate in patients with low-grade B-cell lymphomas. The use of this modality in patients with chronic lymphocytic leukemia (CLL) has been sporadic in clinical trials and was hampered by the extensive marrow involvement seen commonly in patients with CLL, which would produce a high risk for marrow aplasia after treatment with RIT. Herein, we report our experience with RIT in 5 patients with CLL or SLL showing short-lived responses and significant myelosuppression. After 90Y-ibritumomab tiuxetan treatment, the median time to relapse was 65 days, and no cases of MDS or AML were observed during follow-up. All patients experienced grade ≥3 thrombocytopenia and neutropenia, with median durations of 39.5 days and 107 days, respectively.