ASH 2017: Busulfan Plus Melphalan Versus Melphalan Alone in Multiple Myeloma
In a randomized phase III trial, the combination of busulfan and melphalan as a preparatory regimen for autologous hematopoietic stem cell transplantation in patients with multiple myeloma was associated with significantly improved progression-free survival compared with high-dose melphalan alone.
Most of the study team, including lead author Muzaffar H. Qazilbash, MD, was affiliated with The University of Texas MD Anderson Cancer Center in Houston. The two-drug regimen was demonstrated to be safe, and, versus melphalan alone, “the significant difference in progression-free survival continued even after adjusting for maintenance therapy,” Dr. Qazilbash noted in a presentation at the 2017 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstract 399).
A total of 204 patients, enrolled between 2011 and 2017, were randomized about equally to the 2 arms. Using Kaplan-Meier estimates, the median progression-free survival was 64.7 months in the 2-drug arm and 34.4 months in the melphalan-alone arm (P = .013).
One possible explanation for the longer progression-free survival is “selective targeting of clonogenic myeloma progenitor cells” by bulsulfan and melphalan, Dr. Qazilbash concluded. Another is “deeper MRD [minimal residual disease] negativity” with the combination, although the difference between the percentages who achieved MRD-negative status in the combination (58%) and melphalan-alone (61%) arms was not significant (P = .75).