Steady-State Versus Chemotherapy-Based Stem Cell Mobilization in Multiple Myeloma: A Single-Center Study to Analyze Efficacy and Safety.

Background: High-dose chemotherapy followed by autologous hematopoietic stem cell support is recommended in the treatment of eligible multiple myeloma (MM) patients. The aim of this study was to compare the efficacy and safety of steady-state versus chemotherapy-based stem cell mobilization in our Hungarian patient population.

Methods: The subjects were 210 MM patients who underwent stem cell mobilization procedure between 2018 and 2022. Solo granulocyte colony-stimulating factor (G-CSF) was administered in 104 cases, while 106 patients received chemotherapy which was followed by G-CSF administration. We evaluated the ratio of successful mobilizations, the amount of collected stem cells, the incidence of infections and cost-effectivity in the two groups.

Results: In the steady-state group, there was a significantly higher need for plerixafor (45% vs. 13%, P < 0.001), unsuccessful stem cell mobilization was more frequent (11% vs. 3%, P = 0.024) and the mean amount of collected stem cells was lower (6.9 vs. 9.8 × 10⁶, P < 0.001) than in the chemotherapy group. However, infections were less frequent (4% vs. 27%, P < 0.001) and the number of days spent in hospital was significantly lower (6 vs. 14 days, P < 0.001). Plerixafor was more frequently administered in those who had received lenalidomide or daratumumab than in those who had been treated with other regimens (41% vs. 23%, P = 0.007 and 78% vs. 23%, P < 0.001, respectively).

Conclusions: Steady-state mobilization is a safe method; however, the higher rate of plerixafor administration and unsuccessful attempts may question its superiority to chemomobilization.