Usefulness of rituximab-based treatment of seven patients with Waldenstrom macroglobulinemia

[Abstract] Waldenstrom macroglobulinemia is relatively rare, accounting for approximately 2% of all hematological malignancies, with an annual incidence of 2 - 3 per million, median age at presentation of 64 years, and overall survival of 60 months. The aim of treatment should be to improve the quality and duration of life with minimal side effects in the most cost-effective manner. We retrospectively investigated the clinical characteristics and treatment of seven elderly patients with Waldenstrom macroglobulinemia in our institute. The median age of patients was 72 years (range : 62-77) and median serum IgM level was 2,975 mg/dL (range : 1033 - 6806). 3 patients were treated with rituximab alone (375 mg/m2, once a month for 8 months), and 4 patients were treated with rituximab 375 mg/m2 on day 1 and oral fludarabine 25 mg/m2 on days 2 - 6 every 4 weeks for 6 courses. Rituximab alone was effective, with 1 CR, 1 PR, and 1 SD, and no toxicity being reported. The rituximab and fludarabine treatment was also effective, with 4 PR. The main toxicity observed was hematological, and there were no severe infections. The rituximab and fludarabine treatment was an effective therapy ; however, myelosuppression may pose a problem in patients. Patients can tolerate long-term treatment with the clinically stable rituximab alone, which is necessary to investigate the optimal regimen and maintenance therapy for rituximab.