Application of the Conditioning Regimen with Busulfan and Cyclophosphamide in Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma

Backgroud Busulfan isthe most commonly used drug in conditioning regimens for hematopoietic stem cell transplantation, and high-dose melphalan (HDM)is the standard conditioning regimen in autologous stem cell transplantation(ASCT)for multiple myeloma. Studies have shown that in ASCT for multiple myeloma, conditioning regimens containing busulfan is equally effective as HDM.

Aims Evaluate the safety and efficacy of BUCY( busulfan and cyclophosphamide ) conditioning regimen for autologous hematopoietic stem cell transplantation(ASCT)in patients with multiple myeloma(MM).

Methods We retrospectively analyzed the clinical data of 72 MM patients who received transplantation in the Hematology Department of the First People's Hospital of Soochow University from May 2012 to June 2015. Among them, 36 patients underwent BUCY regimen, while the others received HDM regimen. Those were compared between the two groups including the complication, the hematopoietic reconstitution and the post-transplantation efficacy.

Results There were no significant differences in age, stage, induction therapy, mobilization method between the two groups. The transplantation-related adverse events were similar in both groups but the incidence of pulmonary infection and bloodstream infection were slightly higher in BUCY group .The median time to neutrophil engraftment in the BUCY and HDM groups were 10(8-17)days versus 10(9-13)days, taking the same time on average(P=0.046). On the other hand, the median time to platelet engraftment was 10(8-18)versus 11(9-47)days accordingly (P=0.017). The TRM in both group was 2.7%. The SCR/CR rates after ASCT (47.2% and 50.0%) were higher than those before it (38.9% and 26.6%) in both groups. In the BUCY group, the median follow-up was 12.5(0-26) months. Six patients (16.7%) underwent disease progression. The 2-year progression-free survival(PFS) rate was 68%. Correspondingly, in the HDM group, the median follow-up time was 23 (0-38) months. Fifteen patients (41.7%) developed disease progression and the 2-year PFS rate was 55%.

Conclusion The BUCY regimen is a safe and effective therapy for ASCT in patients with multiple myeloma. Besides, BUCY regimen is not inferior to HDM regimen. In conclusion, BUCY regimen may replace HDM regimen as a standard conditioning regimen for ASCT in multiple myeloma.