Fludarabine plus cyclophosphamide and rituximab in Waldenstrom macroglobulinemia

Abstract

The combination of fludarabine, cyclophosphamide, and rituximab (FCR) has produced promising results in chronic lymphocytic leukemia and other lymphoproliferative disorders. The authors report the final results from a multicenter, prospective study examining FCR in Waldenstrom macroglobulinemia (WM). Forty-three patients with symptomatic WM that was untreated or pretreated with 1 line of chemotherapy received rituximab 375 mg/m(2) intravenously on day 1 and fludarabine 25 mg/m(2) and cyclophosphamide 250 mg/m(2) intravenously on days 2 through 4. FCR was repeated every 28 days for up to 6 courses. The overall response rate was 79%, and the major response rate of 74.4%, including 11.6% complete remissions (CRs) and 20.9% very good partial remissions. An amelioration of the quality of responses was observed during follow-up, leading to 18.6% of CRs. No differences in terms of responses were observed among previously treated or untreated patients. Among the clinical and laboratory features that were considered, only the β2-microglobulin level had a significant impact in terms of achieving a major response. The major toxicity reported was grade 3/4 neutropenia, which occurred in 45% of courses and was the main reason for treatment discontinuation. After the end of treatment, 19 patients (44%) had long-lasting episodes of neutropenia. Three patients developed myelodysplastic syndrome during follow-up. The FCR regimen was capable of neutralizing adverse prognostic factors and proved to be active in patients with WM, leading to rapid disease control and good-quality responses. Because myelosuppression was the main concern, further studies are warranted to optimize dosages and treatment duration.