High-dose therapy with autologous haemopoietic stem cell support for Waldenström's macroglobulinaemia.

Standard doses of alkylating agents or purine analogues effect response rates of up to 50% in Waldenström's macroglobulinaemia (WM); however, complete responses are infrequent and there are no cures. We have evaluated the feasibility, safety and efficacy of high-dose chemotherapy with peripheral blood stem cell support in six patients aged 45-69 years (median 51.5) with WM; four patients relapsed after prior therapy inclusive of purine analogues and two patients proceeded with transplant after minimal therapy. Four patients mobilized adequate numbers of stem cells; however, two patients with more extensive fludarabine therapy failed to mobilize and required a second attempt at stem cell collection. Five patients were treated with melphalan 200 mg/m2, including one patient who received tandem transplants and one patient who received melphalan 140 mg/m2 with added total body irradiation (TBI). There was no treatment-related mortality and non-haematological toxicities were manageable. Engraftment was prompt except in one patient with extensive prior use of fludarabine. All the six patients achieved at least partial response (PR), including one who achieved complete response (CR). Five patients are alive and four are event-free at 52+, 15+, 12+ and 2+ months post transplant. This pilot study suggests safety and efficacy of high-dose therapy in WM and suggests that the peripheral blood stem cells should preferably be procured prior to extensive use of purine analogues.