Melphalan versus melphalan plus busulphan in conditioning to autologous stem cell transplantation for low-risk multiple myeloma.

Introduction: High-dose chemotherapy conditioning regimens for autologous stem cell transplantation generally give similar results in multiple myeloma. We compared two regimens: melphalan versus melphalan plus busulphan.

Methods: In all, 30 untreated patients with stage III low-risk multiple myeloma were studied. After induction with three VAD courses and mobilization with cyclophosphamide 7 g/m(2) and recombinant human granulocyte-colony stimulating factor (rHuG-CSF) (10 microg/kg b.w./die), they received melphalan 200 mg/m(2) (arm A) or busulphan 16 mg/kg plus melphalan 100 mg/m(2) (arm B) for conditioning for transplantation. All patients received maintenance therapy with Interferon 3 MU x 3/week.

Results: Time to engraftment after transplantation was similar in both groups. All patients received rHuG-CSF after reinfusion of peripheral stem cells. No differences emerged in transplant-related infective and noninfective complications. There were no transplant-related deaths. A better response was observed in the melphalan plus busulphan regimen (85 versus 75%, P<0.05). The 5-year overall survival with this regimen was 56 versus 49% with melphalan, and the median survival was 126 months versus 108 months for melphalan (P=0.7). The median progression-free survival was 121 months for melphalan plus busulphan versus 97 months for melphalan (P=0.05).

Conclusion: These two conditioning regimens showed similar overall response rate and overall survival, though progression-free survival was better with busulphan plus melphalan.