Plerixafor + G-CSF boosts stem cell mobilization and reduces toxicity versus chemotherapy in multiple myeloma

Autologous stem cell transplantation (ASCT) is the standard of care for eligible patients with multiple myeloma (MM), a plasma cell malignancy. However, the optimal stem cell mobilization strategy remains a critical debate, especially with the integration of novel therapeutic agents. Traditional chemotherapy-based mobilization regimens often carry significant toxicity, leading to complications like severe myelosuppression and infection. There is a clear need for more effective and safer methods to achieve robust peripheral blood stem cell collection, ensuring successful transplantation and minimizing patient morbidity.

This single-center observational propensity score-matched cohort study compared two stem cell mobilization strategies in 119 patients with multiple myeloma. Initially, 56 patients received Plerixafor + G-CSF and 63 received Etoposide + Cyclophosphamide + G-CSF. To minimize bias, 37 patients from each group were propensity-matched based on baseline characteristics. Researchers evaluated the efficacy by measuring peripheral blood CD34+ cell counts and yields, and assessed safety by monitoring adverse events like neutropenia, antibiotic use, and transfusion requirements. Engraftment kinetics and survival outcomes were also analyzed.

Compared to the etoposide/cyclophosphamide group, mobilization with Plerixafor + G-CSF demonstrated significantly superior efficacy and safety. The median peripheral blood CD34+ cell concentration was higher (79 vs. 65.1 cells/μL, p=0.038), and the CD34+ cell yields were substantially greater (9.58 vs. 5.70 × 10^6/kg, p=0.009).

All patients (100%) in the Plerixafor + G-CSF group achieved successful mobilization, compared to only 72% of patients (p=0.002) in the etoposide/cyclophosphamide group. Furthermore, the Plerixafor + G-CSF cohort experienced significantly fewer episodes of grade ≥4 neutropenia (13.51% vs. 51.35%, p=0.001), reduced antibiotic use (p=0.001), and less need for red blood cell (p=0.021) and platelet transfusions (p=0.019). Engraftment was also faster, with neutrophil recovery in 11 days vs. 12 days (p=0.034) and platelet recovery in 10 days vs. 11 days (p=0.023). No major differences in progression-free survival (PFS) or overall survival (OS) were observed between the groups.