The comparison of cyclophosphamide at different dose levels for stem cell mobilization in multiple myeloma

Background: We conducted a multi-center retrospective non-randomized study to clarify roles of 2 and 3 gr/m² doses of Cyclophosphamide (Cy) for stem cell mobilization in Multiple Myeloma. Material and methods: This study analyzed 169 adult patients who received Cy-based mobilization regimen at doses 2 and 3 gr/m² between 2018 and 2024. All patients included in this study were 18 years old and older. Patients divided into two groups; group 1 represents 2 gr/m² treated patients, and group 2 represents 3 gr/m² dosing. These two groups then compared in terms of CD34⁺ cell number collected by apheresis, apheresis days, peak peripheral blood CD34⁺ value and rates of mobilization failures. Results: Higher doses of Cy yielded more hematopoietic stem cells compared to the lower dose Cy [10.00 (3.00–28.90) vs 9.01 (5.00–14.90), p = 0.002]; while mobilization failures and apheresis days were comparable across groups (p = 0.112 and p = 0.648, respectively). Apheresis days required for adequate stem cell harvest among groups was found statistically similar (p = 0.648). Conclusion: This study indicated the superior efficacy of 3 gr/m² dose of Cy in terms of stem cell yield. However, mobilization failure and prolonged apheresis sessions were not issues with lower doses.