Background: Autologous stem cell transplantation (auto‐SCT) is a widely used treatment option in multiple myeloma (MM) patients. The optimal graft cellular composition is not known.Study design and methods: Autograft cellular composition was analyzed after freezing by flow cytometry in 127 MM patients participating in a prospective multicenter study. The impact of graft cellular composition on hematologic recovery and outcome after auto‐SCT was evaluated.Results: A higher graft CD34⁺ cell content predicted faster platelet recovery after auto‐SCT in both the short and long term. In patients with standard‐risk cytogenetics, a higher graft CD34⁺ count (>2.5 × 10⁶/kg) was linked with shorter progression‐free survival (PFS; 28 vs. 46 months, p = 0.04), but there was no difference in overall survival (OS) (p = 0.53). In a multivariate model, a higher graft CD34⁺CD133⁺CD38⁻ (>0.065 × 10⁶/kg, p = 0.009) and NK cell count (>2.5 × 10⁶/kg, p = 0.026), lenalidomide maintenance and standard‐risk cytogenetics predicted better PFS. In contrast, a higher CD34⁺ count (>2.5 × 10⁶/kg, p = 0.015) predicted worse PFS. A very low CD3⁺ cell count (≤20 × 10⁶/kg, p = 0.001) in the infused graft and high‐risk cytogenetics remained predictive of worse OS.Conclusions: Autograft cellular composition may impact outcome in MM patients after auto‐SCT. More studies are needed to define optimal graft composition.

Background: Multiple myeloma is currently the leading indication for autologous hematopoietic cell transplantation (AHCT). A prerequisite for AHCT is mobilization and collection of adequate blood graft to support high-dose therapy. Current mobilization strategies include granulocyte colony-stimulating factor (G-CSF) alone or in combination with chemotherapy most commonly cyclophosphamide (CY). More recently, plerixafor has become into agenda especially in patients who mobilize poorly. In the selection of a mobilization method, several factors should be considered. Summary: Preplanned collection target is important as G-CSF plus plerixafor is more effective in the mobilization of CD34+ cells than G-CSF alone. On the other hand, CY plus G-CSF is superior to G-CSF only mobilization. Previous therapy and age of the patients are important considerations as G-CSF alone may not be effective enough in patients with risk factors for poor mobilization. These factors include extensive lenalidomide exposure, irradiation to bone marrow-bearing sites, higher age, or a previous mobilization failure. Also, local preferences and experiences as well as the number of apheresis needed are important issues as well as cost-effectiveness considerations. Mobilization method used may have implication for cellular composition of collected grafts, which might have an impact on posttransplant events such as hematologic and immune recovery in addition to also potential long-term outcomes. Key Message: Currently, G-CSF alone and preemptive plerixafor if needed might be considered as a standard mobilization strategy in MM patients intended for AHCT.

Primary central nervous system lymphoma is a rare but aggressive brain malignancy. It is associated with poor prognosis even with the current standard of care. The aim of this study was to evaluate the effect and tolerability of blood–brain barrier disruption treatment combined with high-dose treatment with autologous stem cell transplantation as consolidation on primary central nervous system lymphoma patients. We performed a prospective phase II study for 25 patients with previously untreated primary central nervous system lymphoma. The blood–brain barrier disruption treatment was initiated 3–4 weeks after the MATRix regimen using the previously optimized therapy protocol. Briefly, each chemotherapy cycle included two subsequent intra-arterial blood–brain barrier disruption treatments on days 1 and 2 via either one of the internal carotid arteries or vertebral arteries. Patients received the therapy in 3-week intervals. The treatment was continued for two more courses after achieving a maximal radiological response to the maximum of six courses. The complete treatment response was observed in 88.0% of the patients. At the median follow-up time of 30 months, median progression-free and overall survivals were not reached. The 2-year overall and progression-free survival rates were 67.1% and 70.3%, respectively. Blood–brain barrier disruption treatment is a promising option for primary central nervous system lymphoma with an acceptable toxicity profile.