Objectives To assess the feasibility of reduced cyclophosphamide dosing in the setting of mobilization chemotherapy prior high dose chemotherapy and autologous stem cell transplantation in patients with systemic sclerosis. The primary end point was the occurrence of ‘poor mobilization’ when using different cyclophosphamide dosing. The second end point was to analyze potential risk factors for difficult stem cell mobilization in this cohort of patients with systemic sclerosis. Methods This single-center study retrospectively reviewed 32 patients with systemic sclerosis who underwent autologous stem cell transplantation. We analyze the occurrence of ‘poor mobilization’ (defined as CD34+ progenitor cell count < 2 x 106/kg body weight, the use of increasing G-CSF dose, the use of plerixafor, or leukapheresis on > 2 consecutive days) in different cyclophosphamide mobilization regimens: We herein compared low dose (2x1-1.5g/m2) cyclophosphamide vs high dose (2x2g/m2) for mobilization. Results Higher dosing of cyclophosphamide seems not to be beneficial regarding stem cell collection as there was no significant difference in stem cell yield between high dose and reduced dose cyclophosphamide (6.2 vs 5.2 x106/kg bodyweight after CD34+ enrichment). Furthermore, higher doses of cyclophosphamide might be associated with more side effects, this difference was however not statistically significant. Lower bodyweight and BMI (p< 0.001) as well as Rituximab pre-therapy (p< 0.05) and cardiac involvement (p< 0.01) might negatively impact stem cell collection independently from the chosen regimen. Conclusion Our data demonstrate that a reduced cyclophosphamide mobilization regimen seems to be feasible. Risk factors for poor mobilization might be low bodyweight, prior rituximab therapy and cardiac involvement.

中文翻译：

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用于系统性硬化症患者的自体干细胞移植减少环磷酰胺动员是可行的

目的 评估系统性硬化症患者在高剂量化疗和自体干细胞移植前进行动员化疗时减少环磷酰胺剂量的可行性。主要终点是使用不同剂量的环磷酰胺时出现“动员不良”。第二个终点是分析这组系统性硬化症患者干细胞动员困难的潜在危险因素。方法 本单中心研究回顾性分析了 32 例接受自体干细胞移植的系统性硬化症患者。我们分析了“动员不良”（定义为 CD34+ 祖细胞计数 < 2 x 106/kg 体重、使用增加的 G-CSF 剂量、使用普乐沙福或白细胞分离术对 > 连续 2 天）在不同的环磷酰胺动员方案中：我们在此比较了低剂量 (2x1-1.5g/m2) 环磷酰胺与高剂量 (2x2g/m2) 的动员效果。结果 较高剂量的环磷酰胺似乎对干细胞收集没有好处，因为高剂量和低剂量环磷酰胺之间的干细胞产量没有显着差异（CD34+ 富集后 6.2 vs 5.2 x106/kg 体重）。此外，更高剂量的环磷酰胺可能与更多的副作用有关，但这种差异在统计学上并不显着。较低的体重和 BMI (p < 0.001) 以及利妥昔单抗治疗前 (p < 0.05) 和心脏受累 (p < 0.01) 可能独立于所选方案对干细胞收集产生负面影响。结论 我们的数据表明减少环磷酰胺动员的方案似乎是可行的。活动能力差的危险因素可能是低体重、先前的利妥昔单抗治疗和心脏受累。