Fludarabine Combination Therapy Is Highly Effective in First-Line and Salvage Treatment of Patients with Waldenström's Macroglobulinemia

Alkylating agents or single-agent purine analogues are modestly effective as front-line therapy for Waldenström's macroglobulinemia (WM), but response rates of < 50% are exhibited in the salvage therapy setting. Fludarabine combination therapy may be more effective, but no large studies exploring these regimens specifically in WM are available. We report our results of 18 cycles of fludarabine combination therapy: FC (fludarabine 25 mg/m2 for 3 days plus cyclophosphamide 250 mg/m2 for 3 days; n = 9), FM (fludarabine 25 mg/m2 for 3 days plus mitoxantrone 10 mg/m2 for 1 day; n = 3), FCR (FC plus rituximab 375 mg/m2; n = 5), or fludarabine/rituximab (n = 1). Four patients had previously untreated disease, and 14 had pretreated disease; 67% had elevated serum levels of β2-microglobulin, and 86% had hemoglobin levels ≤ 12 g/dL. Patients received a median of 4 cycles (range, 1-6 cycles), with grade ≥ 3 neutropenia and infection complicating 25% and 4% of cycles, respectively. Objective responses (all partial) were attained in 13 patients (76%). Response rates did not significantly differ by regimen, previous treatment, age, performance status, β2-microglobulin level, hemoglobin level, time from diagnosis, previous fludarabine exposure, or alkylator refractoriness. Median remission duration was 38 months; no previously untreated patient had died at a median of 37 months of follow-up, and the actuarial 5-year survival rate was 55% for pretreated patients. No cases of secondary myelodysplasia or leukemia were encountered.