The impact of multiple myeloma induction therapy on hematopoietic stem cell mobilization and collection: 25-year experience

While first-line induction therapy for patients with multiple myeloma has changed over the years, autologous hematopoietic stem cell transplantation still plays a significant role, improving both depth of response and progression-free survival of myeloma patients. Our 25-year experience in mobilizing hematopoietic stem and progenitor cells for 472 transplant-eligible myeloma patients was retrospectively reviewed. Patients were stratified according to the remission induction therapy received, and the outcomes were compared among the cohorts that received vincristine, adriamycin and dexamethasone (VAD) (n=232), bortezomib and dexamethasone (BD) (n=86), cyclophosphamide, bortezomib and dexamethasone (CyBorD) (n=82) and other regimens (n=67). Cyclophosphamide plus granulocyte colony-stimulating factor was the predominant mobilization regimen given. A greater number of CD34⁺ cells (9.9×10E6/kg, p=0.026) was collected with less hospital admissions in BD patients (13%, p=0.001), when compared to those receiving VAD (7.5×10E6/kg, 29%), CyBorD (7.6×10E6/kg, 19%), or other regimens (7.9×10E6/kg, 36%). Induction therapy did not influence the overall rate of unscheduled visits or the length of hospitalization because of complications following mobilization. The myeloma response was not significantly deepened following the cyclophosphamide administered for mobilization. This analysis demonstrates the importance of monitoring the impact of initial treatment on downstream procedures such as stem cell mobilization and collection.