Treatment of Waldenstrom's macroglobulinemia with very low doses of alpha interferon.

Waldenström's macroglobulinemia (WM) is a differentiated B-cell malignancy which is usually less responsive to standard chemotherapy because of low-proliferating cells. Interferon alpha has been shown to possess a therapeutic action in numerous B-cell malignancies including the early stage of chronic lymphocytic leukemia, multiple myeloma, follicular lymphoma and hairy cell leukemia. Fourteen patients with progressive WM were included in a pilot study using very low dose of interferon alpha-2a (1 Million Units 3 times a week). The mean duration of treatment was 10.3 months (range 2-44). Six of 14 (42%) patients presented an increase in the hemoglobin level (> or = 0.9 g/dL) and 4/14 (28%) had a substantial decrease of the monoclonal component (> or = 20% of reduction). Only two patients presented both types of response, while the others with an increase in the hemoglobin level had a slight decrease in the monoclonal component (MC) (1 patient), a stable MC (1 patient) or a slight increase of MC (1 patient). One additional patient had a 15% decrease of the MC with a stable hemoglobin level. Response was observed within 3 months with a median duration of 6 months. Treatment was stopped for 3 patients because of flu-like symptoms (2 patients), or thrombocytopenia (1 patient). Follow up was possible in 12 patients lasting up to a maximum of 30 months after discontinuing treatment. Seven patients died, including 4 with progressive disease, two of infection and one of cardiac failure. In the view of these results, very low dose of interferon alpha may constitute a new approach for treatment of some cases of WM.