Comparative efficacy and safety of G-CSF alone versus G-CSF combined with different doses of cyclophosphamide for peripheral blood stem cell mobilization in patients with multiple myeloma.

OBJECTIVE

Autologous hematopoietic stem cell transplantation (aHSCT) remains a standard treatment for eligible patients with multiple myeloma (MM), and successful mobilization of adequate CD34⁺ cells is critical. This study evaluated the efficacy and safety of G-CSF alone versus G-CSF combined with different doses of cyclophosphamide for peripheral blood stem cell mobilization.

METHODS

In this retrospective, single-center study, 166 patients with MM undergoing first-time mobilization were analyzed. Patients were grouped as follows: G-CSF alone (Group 1), G-CSF plus cyclophosphamide 1-2 g/m² (Group 2), and G-CSF plus cyclophosphamide 3-4 g/m² (Group 3). Successful mobilization was defined as ≥ 2 × 10⁶ CD34⁺ cells/kg. Outcomes included mobilization success, CD34⁺ yield, apheresis requirements, and toxicity.

RESULTS

Mobilization success rates were 60.6%, 84.8%, and 97.6% in Groups 1, 2, and 3, respectively (p < 0.001). CD34⁺ cell yield increased with higher cyclophosphamide doses, with the highest yield in Group 3 (p < 0.001). Multivariate analysis showed that cyclophosphamide significantly improved mobilization success (Group 2: OR 4.57, p = 0.007; Group 3: OR 21.94, p = 0.005). Fewer apheresis sessions were required in higher-dose groups. No significant differences were observed in febrile neutropenia or platelet transfusion rates.

CONCLUSION

Adding cyclophosphamide to G-CSF significantly improves mobilization success and CD34⁺ yield in MM patients. Higher cyclophosphamide doses provide superior efficacy without increased toxicity, supporting chemo-mobilization as an effective and safe strategy in selected patients.