Impact of the Conditioning Regimen in Patients With Multiple Myeloma Who Undergo Autologous Transplantation

Abstract

TO THEEDITOR:Recently,Regelinketal 1 reportedthelong-term results of a series of 90 patients with multiple myeloma (MM) who underwent either single or tandem autologous stem-cell transplantation. Conditioning regimens that were administered for the first and second transplantation were high-dose melphalan (MEL) and the combination of busulfan (BU) and cyclophosphamide, respectively. The authors reported a significantly higher 10-year overall survival and event-free survival for patients in the tandem transplantation group. According to their hypothesis, the better outcomes that were observed in patients who underwent tandem transplantation were only a result of the greater amount of chemotherapy administered in this group of patients; this suggests that these results would have been achieved regardless of the conditioning regimen that was administered in the second transplantation. However, and in contrast to the opinion of Regelink et al, we believe that the use of a preparative regimenthatcombinedtwoalkylatingagentsinthesecondtransplantation could have played a key role in the encouraging long-term results that were reported by the authors. In this regard, when two conditioning regimens (MEL v BU MEL, or BUMEL) were pro