Peripheral blood progenitor cell mobilization for autologous and allogeneic hematopoietic cell transplantation: guidelines from the American Society for Blood and Marrow Transplantation

[Haematopoietic stem cell donation from minor donor: Respecting laws, assessing fitness, delivering information and good care (SFGM-TC)]

Haematopoietic stem cell collection from paediatric donors is a common and life-saving practice, as evidenced by the fact that there is a growing annual number of cases of transplants from minor donors among SFGM-TC centers over the last decade. Still, medical use of human tissue from a healthy and underage donor requires proper regulations and medical management. The guidelines below aim at underlining the importance of pondering the legal, medical and ethical aspects of using stem cells from healthy paediatric donors and stress out the importance of obtaining informed consent at the time of assessing HLA compatibility. Combined medical and psychological assessments are required before the donation, as well as one month later and one year later to ensure of the child's physical and mental wellbeing. Bone marrow harvest under general anaesthetics remains the preferred method of collection for children. Peripheral blood stem cell collection should only be considered for children who will not require a central venous access for collection. We aim at offering guidelines centered on the healthy child donating stem cells and his/her wellbeing, and these should be regularly reviewed as medical practices evolve.

Poor Mobilization-Associated Factors in Autologous Hematopoietic Stem Cell Harvest

Peripheral blood stem cell transplantation (PBSCT) is an important therapeutic measure for both hematologic and non-hematologic diseases. For PBSCT to be successful, sufficient CD34+ cells need to be mobilized and harvested. Although risk factors associated with poor mobilization in patients with hematologic diseases have been reported, studies of patients with non-hematologic diseases and those receiving plerixafor are rare. To identify factors associated with poor mobilization, data from autologous PBSC harvest (PBSCH) in 491 patients were retrospectively collected and analyzed. A multivariate analysis revealed that in patients with a hematologic disease, an age older than 60 years (odds ratio [OR] 1.655, 95% confidence interval [CI] 1.049-2.611, p = 0.008), the use of myelotoxic agents (OR 4.384, 95% CI 2.681-7.168, p < 0.001), and a low platelet count (OR 2.106, 95% CI 1.205-3.682, p = 0.009) were associated with poor mobilization. In patients with non-hematologic diseases, a history of radiation on the pelvis/spine was the sole associated factor (OR 12.200, 95% CI 1.934-76.956, p = 0.008). Among the group of patients who received plerixafor, poor mobilization was observed in 19 patients (19/134, 14.2%) and a difference in the mobilization regimen was noted among the good mobilization group. These results show that the risk factors for poor mobilization in patients with non-hematologic diseases and those receiving plerixafor differ from those in patients with hematologic diseases; as such, non-hematologic patients require special consideration to enable successful PBSCH.

Peripheral blood stem cell harvesting in young children weighing less than 15 kg

Autologous peripheral blood stem cell (PBSC) transplantation is crucial in pediatric cancer treatment, and tandem transplantation is beneficial in certain malignancies. Collecting PBSCs in small children with low body weight is challenging. We retrospectively analyzed data of pediatric cancer patients weighing <15 kg who underwent autologous PBSC harvesting in our hospital. Collections were performed in the pediatric intensive care unit over 2 or 3 consecutive days, to harvest sufficient stem cells (goal ≥2 × 106 CD34+ cells/kg per apheresate). From April 2006 to August 2021, we performed 129 collections after 50 mobilizations in 40 patients, with a median age of 1.9 (range, 0.6-5.6) years and a body weight of 11.0 (range, 6.6-14.7) kg. The median CD34+ cells in each apheresate were 4.2 (range, 0.01-40.13) × 106/kg. 78% and 56% of mobilizations achieved sufficient cell dose for single or tandem transplantation, respectively, without additional aliquoting. The preapheresis hematopoietic progenitor cell (HPC) count was highly correlated with the CD34+ cell yield in the apheresate (r = 0.555, P < 0.001). Granulocyte colony-stimulating factor alone was not effective for mobilization in children ≥2 years of age, even without radiation exposure. By combining the preapheresis HPC count ≥20/μL and the 3 significant host factors, including age <2 years, no radiation exposure and use of chemotherapy, the prediction rate of goal achievement was increased (area under the curve 0.787).

Efficacy and Safety of Single-dose Pegfilgrastim for CD34 + Cell Mobilization in Healthy Volunteers: A Phase 2 Study

BACKGROUND

Pegfilgrastim, a long-acting form of granulocyte-colony stimulating factor, with a convenient single-injection dosage, is being investigated for peripheral blood stem cell (PBSC) mobilization in healthy volunteers. However, data on the adequate dose of pegfilgrastim for PBSC mobilization are limited. This phase 2, single-arm study evaluated the efficacy and safety of pegfilgrastim for PBSC mobilization in healthy volunteers.

METHODS

The study comprised 2 phases: pilot (steps 1-3, dose escalation, a single subcutaneous dose of 3.6, 7.2, and 10.8 mg pegfilgrastim, respectively) and evaluation (step 4, efficacy and safety assessments). The primary endpoint was the proportion of subjects who achieved mobilization of ≥20 × 10 6 /L cluster of differentiation 34 positive (CD34 + ) cells.

RESULTS

Thirty-five subjects (6 each in steps 1 and 2 and 23 in step 4) were included. In the pilot phase, step 3 with a 10.8 mg dose was not conducted due to favorable outcomes in step 2 (desired CD34 + cell count), at 7.2 mg pegfilgrastim, which was identified as the optimal dose for the evaluation phase. In the evaluation phase, successful CD34 + mobilization was achieved in all 23 subjects. The mean peripheral blood CD34 + cells count peaked on day 5. Back pain, thrombocytopenia, transient elevations of alkaline phosphatase, and lactate dehydrogenase were the most common adverse events. All adverse events were mild, and none led to study discontinuation.

CONCLUSIONS

A single-dose pegfilgrastim successfully mobilized an optimal number of CD34 + cells and was well tolerated. Pegfilgrastim could be an alternative option for PBSC mobilization in healthy volunteers. The trial was registered at www.clinicaltrials.gov (NCT03993639).

Risk factors of early disease progression and decreased survival for multiple myeloma patients after upfront autologous stem cell transplantation

Multiple myeloma (MM) stands as the second most prevalent hematological malignancy, constituting approximately 10% of all hematological malignancies. Current guidelines recommend upfront autologous stem cell transplantation (ASCT) for transplant-eligible MM patients. This study seeks to delineate factors influencing post-ASCT outcomes in MM patients. Our cohort comprised 150 MM patients from Taipei Veterans General Hospital, with progression-free survival (PFS) as the primary endpoint and overall survival (OS) as the secondary endpoint. A Cox proportional hazards model was employed to discern potential predictive factors for survival. ASCT age ≥ 65 (hazard ratio [HR] 1.94, 95% confidence interval [CI] 1.08-3.47) and the presence of extramedullary disease (HR 2.53, 95% CI 1.53-4.19) negatively impacted PFS. Conversely, treatment response ≥ VGPR before ASCT (HR 0.52, 95% CI 0.31-0.87) and total CD34+ cells collected ≥ 4 × 106 cells/kg on the first stem cell harvesting (HR 0.52, 95% CI 0.32-0.87) were positively associated with PFS. For OS, patients with ISS stage III (HR 2.06, 95% CI 1.05-4.04), the presence of extramedullary disease (HR 3.92, 95% CI 2.03-7.58), light chain ratio ≥ 100 before ASCT (HR 7.08, 95% CI 1.45-34.59), post-ASCT cytomegalovirus infection (HR 9.43, 95% CI 3.09-28.84), and a lower conditioning melphalan dose (< 140 mg/m2; HR 2.75, 95% CI 1.23-6.17) experienced shorter OS. In contrast, post-ASCT day + 15 absolute monocyte counts (D15 AMC) > 500/µl (HR 0.36, 95% CI 0.17-0.79) and post-ASCT day + 15 platelet counts (D15 PLT) > 80,000/µl (HR 0.48, 95% CI 0.24-0.94) were correlated with improved OS. Significantly, early PLT and AMC recovery on day + 15 predicting longer OS represents a novel finding not previously reported. Other factors also align with previous studies. Our study provides real-world insights for post-ASCT outcome prediction beyond clinical trials.

The Use of a High Flow PICC Catheter for Stem Cell and Lymphocyte Apheresis: The Initial Experience of a Pediatric Oncology Center in Brazil

BACKGROUND

Autologous hematopoietic stem cell transplant (HSCT), characterized by high intensity chemotherapy followed by the infusion of HSC previously collected from the peripheral blood, is a procedure used in the treatment of several malignancies. In pediatrics, the apheresis procedure represents a challenge, due to the need for insertion of a rigid central venous catheter (CVC) in small children. The CVC is usually used for stem cell collection and then removed. Later, the patient will need a new device for cell infusion.

AIM

We propose the use of one single catheter for both apheresis and infusion.

METHODS

We present five children between 1 and 13 years of age who underwent apheresis using a high flow PICC catheter surgically inserted.

RESULTS

All patients utilized a PICC line double lumen 5Fr (PowerPICC™ 5Fr DL BARD/USA) placed in the brachiocephalic vein tunneled on the chest, inserted under 24 h prior to apheresis to assure the devices were pervious. Three of the patients were diagnosed with solid tumor and one with acute lymphoblastic leukemia (ALL) awaiting Car-T Cell therapy. The four children who underwent autologous HSCT used the same catheter for cell infusion and remained with the catheter following discharge. The child who was submitted for Car-T Cell still awaits infusion and the catheter was removed.

CONCLUSIONS

High flow PICC is a viable alternative for apheresis to maintain an adequate flow of 5 ml/s and can be used as a single catheter throughout the HSCT process, reducing the risks from anesthesia and the catheter insertion procedure.

TYPE OF STUDY

Clinical Research.

Safety and efficacy of peripheral blood stem cells collection in healthy children and pediatric patients with thalassemia major weighing 20 kg or less

BACKGROUND

Peripheral blood stem cell (PBSC) collection in children poses challenges due to their small size, low body weight (BW), and unique pediatric physiology, especially among children weighing 20 kg (kg) or less.

METHODS

PBSC collection data of both healthy children and patients with thalassemia major (TM) weighing 20 kg or less between January 2013 and December 2020 were reviewed. Moreover, PBSCs characteristics along with various aspects of efficiency and safety between healthy donors and patients with TM were compared.

RESULTS

A total of 262 PBSC procedures were performed on 255 children. Of these, 91 procedures were carried out on 85 allogeneic healthy donors, and 171 auto-backup collections were performed on 170 patients with TM to ensure PBSC availability and prevent transplantation failure. A minimum pre-apheresis hemoglobin (HGB) level of 60 g/L was discovered to be safe and feasible in patients with TM. The median CD34+ cell dose in the PBSC product during the initial apheresis procedure was higher in healthy donors compared to patients with TM (7.29 ± 5.28 × 106 cells/kg vs5.88 ± 4.23 × 106 cells/kg, P = .043). The total CD34+ cells/kg recipient weight exhibited a positive correlation with pre-apheresis monocyte counts, but a negative correlation with donor weight. Apheresis significantly reduced hematocrit and platelet counts in the allogeneic group compared to the autologous group. Patients with TM experienced a higher occurrence of bone pain related to granulocyte colony-stimulating factor treatment. Notably, no serious complications related to PBSCs mobilization, central venous catheter placement, or the apheresis procedure were observed in either group.

CONCLUSIONS

PBSCs collection was both safe and effective in healthy children and pediatric patients with TM weighing 20 kg or less.

The effect of mobilizing large numbers of CD34 + cells (super-mobilizers) on the engraftment and survival in patients undergoing autologous stem cell transplantation

With the use of plerixafor in addition to growth factor for peripheral blood stem cell mobilization, the yield of autologous stem cell harvest has been higher while the length of apheresis days has become shorter. There is still debate whether higher cell collection efficacy in autologous stem cell transplant (ASCT) affect outcomes. In this retrospective study, we defined two groups of patients, group 1, super-mobilizers, with more than double the target cell dose collected (n = 15), while group 2 included all other patients (n = 75). Multiple myeloma (MM) and lymphoma patients were combined. Patients with chemo-mobilization, those needed more than one day apheresis, or with less than 100 days after ASCT were excluded. Correlations were performed between cell collection efficacy and post thaw CD34 cell viability (by 7AAD flow cytometry method), product HCT, and engraftment of neutrophils and platelets. We performed multiple linear regression using the above variables in addition to age, sex and disease type. We used Kaplan Meier's curves to show effect of cell collection efficacy on 1-year overall survival (OS). Our results show that all super-mobilizers received plerixafor in addition to G-CSF, while 83% did in group 2. Correlations between cell collection efficacy and neutrophil and platelet engraftment in group 1 and 2 was modest and better in group 1 (R=0.449 Vs 0.233 for neutrophils; R=0.464 Vs 0.110 for platelets, respectively). However, multiple linear regression showed statistically significant association between cell collection, as a continuous variable, with disease type (P < 0.001), product HCT (P < 0.001), post thaw viability (P = 0.003), and age (P = 0.013). MM patients were more likely to be super-mobilizers, while the product HCT was higher in the super-mobilizers. No significant effect of cell collection efficacy was found on engraftment of neutrophils or platelets. With relatively short post ASCT follow up, 6 patients in group 2 died of any cause while no deaths were recorded in the super-mobilizers group (P = 0.1892 by log-rank test). In conclusion, stem cell collection efficacy in ASCT is more frequent in MM than lymphoma patients, but is not predictive of faster engraftment. On the other hand, 1-year OS was 100% in the super-mobilizers group versus 93% in the other group.

Stem Cells mobilization and collection in allogeneic related and unrelated donors: a single center experience with focus on plerixafor

INTRODUCTION

Poor CD34 + cells mobilization in allogeneic donors could affect transplant outcome. In a subgroup of patient mobilization with granulocyte colony-stimulating factor (G-CSF) alone is unsatisfactory, and Plerixafor could be used to enhance CD34 + cells release from bone marrow niche.

MATERIALS AND METHODS

We conducted a retrospective single-center, cohort study on healthy allogeneic donors both related and unrelated, treated by Udine Transfusion Center over the last 10 years (2012-2022). In the 195 allogeneic donors treated we analyzed age, sex, body weight, BMI, comorbidities, G-CSF dosage and even baseline white blood cell count as possible predictor of insufficient CD34 + cells mobilization on day 5. In the subgroup of related donors we evaluated even baseline CD34 + cells (measured before mobilization start). Processed donor blood volume, collection efficiency and apheresis product were examined. Additionally a comparative analysis was conducted between G-CSF alone treated donors and poor mobilizing ones, in which Plerixafor was administered at a dose of 0.24 mg/kg as a pre-emptive or rescue agent.

RESULTS

In 9 donors, due to poor mobilization (defined as CD34 + < 20/µL or estimated yield < 1 ×106 kg/recipient body weight), the use of plerixafor was necessary. PLX at a dose of 0.24 mg/kg was administered 5 h before collection, inducing an average increase of 5.1 (1.7-12.6) in CD34 + circulating cells. In this subgroup of patients, BMI and weight were significantly lower (p = 0.03). Interestingly, baseline CD34 + cells (measured before the onset of mobilization) also seems to predict poor mobilization (p = 0.003). In donors additionally treated with Plerixafor compared to those who received G-CSF alone, collection efficiency was higher (p = 0.02) and CD34 + cells collected were comparable (p = 0.2). Side effects related to the administration of plerixafor, if they occurred, were well tolerated.

CONCLUSIONS

Plerixafor is a safe and effective drug in the rescue and prevention of poor mobilization. New prospective studies on allogeneic donors should be performed to increase the treatable population to avoid inadequate collection and mobilization. New laboratory predictors such as baseline CD34 + cells should be investigated in larger cohorts and then used as early screening.

Plerixafor in autologous stem cell transplantation: Does it affect engraftment kinetics?

Plerixafor increases stem cell mobilization by reversibly binding to the chemokine receptor CXCR4. In our study, we examined the results of mobilization with plerixafor and granulocyte colony-stimulating factor (G-CSF) and revealed their effects on autologous stem cell transplantation (ASCT) engraftment kinetics. The study included all cases of ASCT performed in the Adult Bone Marrow Transplantation Unit of xxx University between January 2014 and January 2022. It included a total of 300 patients. The total number of CD34 + cells collected was 7.44 ± 4.19 in patients with plerixafor and 9.53 ± 6.09 in patients without plerixafor. The mean neutrophil and platelet engraftment took longer in plerixafor-mobilized patients (neutrophil: 12 ± 4.1 vs. 10.2 ± 2.7 days; platelet: 21.6 ± 13.9 vs. 14.2 ± 5.9 days; p = 0.008 and p = 0.002). The number of febrile neutropenia attacks was significantly higher in plerixafor-mobilized patients (p = 0.04). In the chemo-mobilized patient subgroup, plerixafor-mobilized patients experienced more febrile neutropenia attacks (p = 0.04). The mean time to both neutrophil and platelet engraftment was longer in patients mobilized with plerixafor. In the subgroup of patients with MM, the mean time to platelet engraftment was longer in patients mobilized with plerixafor. Plerixafor and its effect on engraftment kinetics should be evaluated with further studies in a larger population with survival analysis.

Effectiveness of single-dose 6 mg pegfilgrastim in mobilizing peripheral blood stem cells in allogeneic hematopoietic cell transplantation donors

A single injection of 12 mg pegfilgrastim was used to mobilize peripheral blood progenitor cells (PBPCs) from healthy donors in some studies. The purpose of this study was to determine if 6 mg of pegfilgrastim was effective and safe for mobilizing CD34+ cells in donors for allogeneic hematopoietic stem cell transplantation. We conducted a retrospective case-matched design. A single dosage of 6 mg pegfilgrastim was used to mobilize PBPCs from 60 healthy donors. Granulocyte colony-stimulating factor (G-CSF, 10 μg/kg) was administered daily to the matched donors. Leukapheresis was scheduled to commence on day 4 of the mobilization regimen. The median yielded CD34+ cell in the pegfilgrastim group was higher than those in the G-CSF group, at 5.06 × 106/kg recipient weight. The 73.3% of donors mobilized with pegfilgrastim yielded >4 × 106 cells/kg CD34+ cells in a single apheresis procedure when compared to the 33.3% of donors mobilized with G-CSF (P < 0.001). The myeloid-derived suppressor cells (MDSC) proportion in the pegfilgrastim group was significantly higher than that in the G-CSF group (P < 0.001). The cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was higher in the G-CSF group than that in the pegfilgrastim group (26.7% vs. 11.7%), without statistical difference. In comparison to the G-CSF group, the pegfilgrastim group had a reduced median pain intensity numerical rating scale score (1 vs. 2). A single 6 mg dosage of pegfilgrastim is effective and safe for allogeneic PBPCs collection from healthy donors. Pegfilgrastim may decrease the incidence of aGVHD by boosting MDSCs, which need further investigation.

Overview on novel strategies and current guidelines for hematopoietic stem cell mobilisation and collection

The success of the autologous stem cell transplantation is strictly related to an adequate hematopoietic stem cell mobilization and collection. The minimum threshold for a successful mobilization is currently defined as 2 × 106/kg CD34+ cells. However, the optimal stem cell mobilization strategy is still controversial. The availability of plerixafor, a selective and reversible CXCR4 inhibitor, has been associated with an higher use of chemo-free protocols by many centres. In the near future, it is conceivable that artificial intelligence may became more accurate and comprehensive, possibly guiding clinicians in choosing the optimal mobilisation treatment for the various patients undergoing hematopoietic stem cell transplantation. Machine learning-based scoring models may be the basis for the development of "intelligent" mobilisation algorithms.

Comparison of efficacy and toxicity according to etoposide and cytarabine dosing in BEAM conditioning followed by autologous stem cell transplantation in Hodgkin lymphoma

The combination of carmustine, etoposide, cytarabine, and melphalan (BEAM) followed by autologous stem cell transplantation (ASCT) is a commonly used intensification regimen for patients with Hodgkin lymphoma. As etoposide and cytarabine dosing are not defined, we conducted a retrospective, multicenter study, to compare efficacy and toxicity in 130 patients with Hodgkin lymphoma receiving etoposide and cytarabine at either 200 mg/m2/d (n = 50), 400 mg/m2/d (n = 35), or etoposide 200 mg/m2/d and cytarabine 400 mg/m2/d (n = 45). Progression-free survival and overall survival were not associated with the intensity of conditioning. Increased conditioning intensity was associated with longer duration of thrombocytopenia, a higher number of transfused RBC and platelet units and a higher frequency of mucositis, but serious adverse events or infectious complications were not increased. The intensity of BEAM regimen was not associated with survival but with the rate of cytopenia and mucositis advocating for the use of lower dosing in frail patients.

Label-Free CD34+ Cell Identification Using Deep Learning and Lens-Free Shadow Imaging Technology

Accurate and efficient classification and quantification of CD34+ cells are essential for the diagnosis and monitoring of leukemia. Current methods, such as flow cytometry, are complex, time-consuming, and require specialized expertise and equipment. This study proposes a novel approach for the label-free identification of CD34+ cells using a deep learning model and lens-free shadow imaging technology (LSIT). LSIT is a portable and user-friendly technique that eliminates the need for cell staining, enhances accessibility to nonexperts, and reduces the risk of sample degradation. The study involved three phases: sample preparation, dataset generation, and data analysis. Bone marrow and peripheral blood samples were collected from leukemia patients, and mononuclear cells were isolated using Ficoll density gradient centrifugation. The samples were then injected into a cell chip and analyzed using a proprietary LSIT-based device (Cellytics). A robust dataset was generated, and a custom AlexNet deep learning model was meticulously trained to distinguish CD34+ from non-CD34+ cells using the dataset. The model achieved a high accuracy in identifying CD34+ cells from 1929 bone marrow cell images, with training and validation accuracies of 97.3% and 96.2%, respectively. The customized AlexNet model outperformed the Vgg16 and ResNet50 models. It also demonstrated a strong correlation with the standard fluorescence-activated cell sorting (FACS) technique for quantifying CD34+ cells across 13 patient samples, yielding a coefficient of determination of 0.81. Bland-Altman analysis confirmed the model's reliability, with a mean bias of -2.29 and 95% limits of agreement between 18.49 and -23.07. This deep-learning-powered LSIT offers a groundbreaking approach to detecting CD34+ cells without the need for cell staining, facilitating rapid CD34+ cell classification, even by individuals without prior expertise.

Mobilization and Hematopoietic Stem Cell Collection in Poor Mobilizing Patients with Lymphoma: Final Results of the German OPTIMOB Study

Introduction

Successful mobilization and collection of peripheral hematopoietic stem cells (HSCs) are necessary for lymphoma patients eligible for myeloablative chemotherapy with subsequent autologous stem cell transplantation (ASCT). Albeit G-CSF alone or combined with chemotherapy is well-established methods for HSC mobilization, up to 40% of the patients fail to mobilize (poor mobilizer, PM). Plerixafor (PLX) is commonly used in PM patients resulting in increased migration of HSCs into peripheral blood and thus improves the collection outcome.

Methods

The prospective, multicenter, open-label, non-interventional OPTIMOB study assessed mobilization and collection parameter of patients with lymphoma or multiple myeloma to get deep insights in the treatment of those patients in clinical routine focusing on PM patients. PM was defined as follows: (1) no achievement of ≥20 CD34+ progenitor cells/µL before first apheresis, (2) PLX administration at any time point during the observational period, (3) reduction of the initially planned CD34+ progenitor cell yield as necessity due to failed mobilization or HSC collection, and (4) no performance of apheresis due to low CD34+ progenitor level. Primary objective of the study was to assess mobilization success by the proportion of PM patients achieving >2 × 106 CD34+ progenitor cells/kg body weight on the first day of apheresis. Here, the data of the lymphoma cohort are presented.

Results

Out of 238 patients with lymphoma documented in the study, 32% were classified as PM. 87% of them received PLX. Demographic data revealed no obvious differences between PM and good mobilizing (GM) patients. All patients were treated highly individualized prior to mobilization. Majority of all PM patients were able to undergo apheresis (95%) and reached their individual requested CD34+ progenitor cell target (72%). 57% of the PM patients achieved >2.0 × 106 CD34+ progenitor cells/kg body weight on day 1 of apheresis and nearby 70% of them underwent ASCT. Median time to engraftment was similar in PM and GM patients of the lymphoma cohort.

Conclusions

Majority of PM patients with lymphoma were successfully mobilized and underwent ASCT. Most of them received PLX during the study.

Mobilization Strategies in Myeloma Patients Intended for Autologous Hematopoietic Cell Transplantation

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.

Age, CD34+ cell dose, conditioning and pre-transplant cytopenias can help predict transfusion support in lymphoma patients undergoing autologous stem cell transplantation

BACKGROUND AND OBJECTIVES

Autologous stem cell transplant (ASCT) is a widely used therapy for lymphoma patients and can nowadays be performed on an outpatient basis. This study aimed to describe transfusion support in lymphoma patients undergoing ASCT and identify increased or prolonged transfusion requirement predictors.

MATERIALS AND METHODS

A retrospective study of all consecutive lymphoma patients undergoing ASCT between 2010 and 2020.

RESULTS

Out of 226 patients, 145 (64%) received red blood cell (RBC) transfusions, whereas all 226 (100%) required platelet transfusion (PT). Transfusions between Day +1 and +30 were higher in patients over 60 (2 [1-4] vs. 2 [0-2] RBC; p = 0.001 and 4 [2-8] vs. 3 [2-4] PT; p < 0.001); patients with pre-transplant anaemia (4 [2.5-6] vs. 2 [0-2] RBC; p < 0.001 and 5 [3-9] vs. 3 [2-4] PT; p = 0.001); pre-transplant thrombocytopenia (2 [1-4] vs. 2 [0-2] RBC; p < 0.001 and 4 [3-8.5] vs. 2 [1-3] PT; p < 0.001) or CD34+ cell dose <4 × 106 /kg (2 [0-4] vs. 2 [0-2] RBC; p = 0.024 and 4 [2-6] vs. 2 [1-3.5] PT; p < 0.001). RBC transfusion independence was reached later in patients receiving carmustine, cytarabine, etoposide and melphalan (BEAM) (hazard ratio [HR] 1.6; confidence interval [CI] 1.1-2.3) and those requiring RBC before infusion and/or with pre-transplant anaemia (HR 2.2; CI 1.4-3.4). Age above 60 (HR 1.4; CI 1.0-1.9), BEAM conditioning (HR 1.4; CI 1.0-2.0) and pre-transplant thrombocytopenia and/or requiring PT before infusion (HR 1.8; CI 1.4-2.5) entailed longer time until PT independence.

CONCLUSION

These four factors (age ≥60 years; BEAM conditioning, CD34+ dose <4 × 106 /kg and pre-transplant cytopenia and/or Day -10 to 0 transfusion) allowed dividing patients into three groups with significant differences between them regarding the time until transfusion independence.

Granulocyte colony-stimulating factor with or without stem or progenitor cell or growth factors infusion for people with compensated or decompensated advanced chronic liver disease

BACKGROUND

Advanced chronic liver disease is characterised by a long compensated phase followed by a rapidly progressive 'decompensated' phase, which is marked by the development of complications of portal hypertension and liver dysfunction. Advanced chronic liver disease is considered responsible for more than one million deaths annually worldwide. No treatment is available to specifically target fibrosis and cirrhosis; liver transplantation remains the only curative option. Researchers are investigating strategies to restore liver functionality to avoid or slow progression towards end-stage liver disease. Cytokine mobilisation of stem cells from the bone marrow to the liver could improve liver function. Granulocyte colony-stimulating factor (G-CSF) is a 175-amino-acid protein currently available for mobilisation of haematopoietic stem cells from the bone marrow. Multiple courses of G-CSF, with or without stem or progenitor cell or growth factors (erythropoietin or growth hormone) infusion, might be associated with accelerated hepatic regeneration, improved liver function, and survival.

OBJECTIVES

To evaluate the benefits and harms of G-CSF with or without stem or progenitor cell or growth factors (erythropoietin or growth hormone) infusion, compared with no intervention or placebo in people with compensated or decompensated advanced chronic liver disease.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two trial registers (October 2022) together with reference-checking and web-searching to identify additional studies. We applied no restrictions on language and document type.

SELECTION CRITERIA

We only included randomised clinical trials comparing G-CSF, independent of the schedule of administration, as a single treatment or combined with stem or progenitor cell infusion, or with other medical co-interventions, with no intervention or placebo, in adults with chronic compensated or decompensated advanced chronic liver disease or acute-on-chronic liver failure. We included trials irrespective of publication type, publication status, outcomes reported, or language.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane procedures. All-cause mortality, serious adverse events, and health-related quality of life were our primary outcomes, and liver disease-related morbidity, non-serious adverse events, and no improvement of liver function scores were our secondary outcomes. We undertook meta-analyses, based on intention-to-treat, and presented results using risk ratios (RR) for dichotomous outcomes and the mean difference (MD) for continuous outcomes, with 95% confidence intervals (CI) and I2 statistic values as a marker of heterogeneity. We assessed all outcomes at maximum follow-up. We determined the certainty of evidence using GRADE, evaluated the risk of small-study effects in regression analyses, and conducted subgroup and sensitivity analyses.

MAIN RESULTS

We included 20 trials (1419 participants; sample size ranged from 28 to 259), which lasted between 11 and 57 months. Nineteen trials included only participants with decompensated cirrhosis; in one trial, 30% had compensated cirrhosis. The included trials were conducted in Asia (15), Europe (four), and the USA (one). Not all trials provided data for our outcomes. All trials reported data allowing intention-to-treat analyses. The experimental intervention consisted of G-CSF alone or G-CSF plus any of the following: growth hormone, erythropoietin, N-acetyl cysteine, infusion of CD133-positive haemopoietic stem cells, or infusion of autologous bone marrow mononuclear cells. The control group consisted of no intervention in 15 trials and placebo (normal saline) in five trials. Standard medical therapy (antivirals, alcohol abstinence, nutrition, diuretics, β-blockers, selective intestinal decontamination, pentoxifylline, prednisolone, and other supportive measures depending on the clinical status and requirement) was administered equally to the trial groups. Very low-certainty evidence suggested a decrease in mortality with G-CSF, administered alone or in combination with any of the above, versus placebo (RR 0.53, 95% CI 0.38 to 0.72; I2 = 75%; 1419 participants; 20 trials). Very low-certainty evidence suggested no difference in serious adverse events (G-CSF alone or in combination versus placebo: RR 1.03, 95% CI 0.66 to 1.61; I2 = 66%; 315 participants; three trials). Eight trials, with 518 participants, reported no serious adverse events. Two trials, with 165 participants, used two components of the quality of life score for assessment, with ranges from 0 to 100, where higher scores indicate better quality of life, with a mean increase from baseline of the physical component summary of 20.7 (95% CI 17.4 to 24.0; very low-certainty evidence) and a mean increase from baseline of the mental component summary of 27.8 (95% CI 12.3 to 43.3; very low-certainty evidence). G-CSF, alone or in combination, suggested a beneficial effect on the proportion of participants who developed one or more liver disease-related complications (RR 0.40, 95% CI 0.17 to 0.92; I2 = 62%; 195 participants; four trials; very low-certainty evidence). When we analysed the occurrences of single complications, there was no suggestion of a difference between G-CSF, alone or in combination, versus control, in participants in need of liver transplantation (RR 0.85, 95% CI 0.39 to 1.85; 692 participants; five trials), in the development of hepatorenal syndrome (RR 0.65, 95% CI 0.33 to 1.30; 520 participants; six trials), in the occurrence of variceal bleeding (RR 0.68, 95% CI 0.37 to 1.23; 614 participants; eight trials), and in the development of encephalopathy (RR 0.56, 95% CI 0.31 to 1.01; 605 participants; seven trials) (very low-certainty evidence). The same comparison suggested that G-CSF reduces the development of infections (including sepsis) (RR 0.50, 95% CI 0.29 to 0.84; 583 participants; eight trials) and does not improve liver function scores (RR 0.67, 95% CI 0.53 to 0.86; 319 participants; two trials) (very low-certainty evidence).

AUTHORS' CONCLUSIONS

G-CSF, alone or in combination, seems to decrease mortality in people with decompensated advanced chronic liver disease of whatever aetiology and with or without acute-on-chronic liver failure, but the certainty of evidence is very low because of high risk of bias, inconsistency, and imprecision. The results of trials conducted in Asia and Europe were discrepant; this could not be explained by differences in participant selection, intervention, and outcome measurement. Data on serious adverse events and health-related quality of life were few and inconsistently reported. The evidence is also very uncertain regarding the occurrence of one or more liver disease-related complications. We lack high-quality, global randomised clinical trials assessing the effect of G-CSF on clinically relevant outcomes.

Physical biomarkers for human hematopoietic stem and progenitor cells

Adhesion of hematopoietic stem and progenitor cells (HSPCs) to the bone marrow niche plays critical roles in the maintenance of the most primitive HSPCs. The interactions of HSPC-niche interactions are clinically relevant in acute myeloid leukemia (AML), because (i) leukemia-initiating cells adhered to the marrow niche are protected from the cytotoxic effect by chemotherapy and (ii) mobilization of HSPCs from healthy donors' bone marrow is crucial for the effective stem cell transplantation. However, although many clinical agents have been developed for the HSPC mobilization, the effects caused by the extrinsic molecular cues were traditionally evaluated based on phenomenological observations. This review highlights the recent interdisciplinary challenges of hematologists, biophysicists and cell biologists towards the design of defined in vitro niche models and the development of physical biomarkers for quantitative indexing of differential effects of clinical agents on human HSPCs.

Determination of the relationship between CD34+ stem cell amount and DMSO in hematopoetic stem cell transplantation

It is important to calculate the CD34+ stem cell (SC) count at the right time in patients with hematological malignancies who will undergo Hematopoietic Stem Cell Transplantation (HSCT). The amount of SC infused into the patient affects the engraftment time and healing process of the patient. In this study, we aimed to compare which of the DMSO-not removed and DMSO-removed samples showed the CD34 + SC amount more accurately as the SC amount determination method after the SC was dissolved after cryopreservation in patients who will undergo HSCT. A total of 22 patients were included in the study. All 22 patients were transplanted from frozen samples using DMSO. After the SC products were dissolved in a 37 °C water bath, they were washed 2 times and the amount of CD34+ SC was studied from the samples taken by removing DMSO and without removing DMSO. In the findings, the amounts of CD34+ SC studied with both methods were compared. The increase in the number and percentage of CD34+ SC after DMSO-removed was found to be statistically significant both in terms of difference and proportionally, and the calculated effect sizes also showed that the increase was clinically significant (Cohen's d is between 0.43 and 0.677). After thawing the frozen SCs of the patients who will undergo HSCT, the analysis of CD34+ SCs from which DMSO is removed provides a more accurate calculation of the CD34+ SC amount in the AP.

Stem cell mobilization in multiple myeloma: challenges, strategies, and current developments

Among hematological malignancies, multiple myeloma (MM) represents the leading indication of autologous hematopoietic stem cell transplantation (auto-HCT). Auto-HCT is predominantly performed with peripheral blood stem cells (PBSCs), and the mobilization and collection of PBSCs are essential steps for auto-HCT. Despite the improved success of conventional methods with the incorporation of novel agents for PBSC mobilization in MM, mobilization failure is still a concern. The current review comprehensively summarizes various mobilization strategies for mobilizing PBSCs in MM patients and the evolution of these strategies over time. Moreover, existing evidence substantiates that the mobilization regimen used may be an important determinant of graft content. However, limited data are available on the effects of graft characteristics in patient outcomes other than hematopoietic engraftment. In this review, we discussed the effect of graft characteristics on clinical outcomes, mobilization failure, factors predictive of poor mobilization, and potential mobilization regimens for such patients.

Benefits of plerixafor for mobilization of peripheral blood stem cells prior to autologous transplantation: a dual-center retrospective cohort study

BACKGROUND AIMS

Before autologous stem cell transplantation (ASCT), hematopoietic stem cells must be stimulated to move from the bone marrow to the peripheral blood for harvesting. Plerixafor, a C-X-C chemokine receptor type 4 antagonist, is used to increase stem cell harvests. However, the effects of plerixafor on post-ASCT outcomes remain unclear.

METHODS

In a dual-center retrospective cohort study of 43 Japanese patients who received ASCT, the authors compared transplantation outcomes in patients who underwent stem cell mobilization with granulocyte colony-stimulating factor with (n = 25) or without (n = 18) plerixafor.

RESULTS

The number of days to neutrophil and platelet engraftment was significantly shorter with plerixafor than without plerixafor, as assessed by univariate (neutrophil, P = 0.004, platelet, P = 0.002), subgroup, propensity score matching and inverse probability weighting analyses. Although the cumulative incidence of fever was comparable with or without plerixafor (P = 0.31), that of sepsis was significantly lower with plerixafor than without (P < 0.01). Thus, the present data indicate that plerixafor leads to earlier neutrophil and platelet engraftment and a reduction of infectious risk.

CONCLUSIONS

The authors conclude that plerixafor may be safe to use and that it reduces the risk of infection in patients with a low CD34+ cell count the day before apheresis.

Day -1 CD34+ Cells and Platelet Count Predict the Number of Apheresis in Poor-Mobilizer Patients Rescued by Plerixafor

Plerixafor is widely used as up-front treatment with G-CSF to enhance peripheral blood hematopoietic stem cell output in patients failing previous mobilizations. Less frequently, plerixafor is used to rescue an unsatisfactory mobilization following chemotherapy (CT) and G-CSF. This study investigates if pre-collection factors affect the CD34+ cell harvest in chemotherapy and G-CSF mobilizations rescued by plerixafor. Clinical and hematological data relative to patients, mobilization, and apheresis products were retrospectively examined. The outcome was completing a target cell dose ≥ 2 × 10⁶ CD34+ cells/kg at first apheresis. The effect exerted on the outcome by patient- and disease-related factors was investigated by univariate and multivariate logistic regression analysis. The analysis included data from 42 patients affected by hematological (39 patients) and non-hematological malignancies (three patients). Twenty-nine patients (69%) attained the target cell dose at first apheresis. Twelve out of the remaining 13 patients received an additional plerixafor administration, and all accomplished the transplant dose at a second apheresis procedure. Day -1 CD34+ PB count (OR1.46, 95% CI 1.1-1.9, p = 0.008) and platelet count (OR1.0, 95% CI 1.0-1.0, p = 0.033) predicted the achievement of the target dose at first apheresis, independently of pre-mobilization CT, radiation therapy, and disease status at mobilization. At ROC curve analysis, the best cut-off value predicting the successful collection at first apheresis was 7.5/µL for Day -1 CD34+ cell count (AUC 0.830, 0.69 sensitivity, and 0.92 specificity) and 75 × 10⁹/L for Day -1 platelet count (AUC = 0.736, 0.65 sensitivity and 0.85 specificity). In conclusion, on-demand plerixafor rescue allows a successful stem cell collection, irrespectively of disease type and status, prior CT lines, and radiation exposure. Pre-apheresis CD34+ cells and platelet count predict the need for one or two aphereses.

Non-Clinical Cell Therapy Development Using the NCG Mouse Model as a Test System

The NCG triple immunodeficient mice on a NOD/Nju background lack functional/mature T, B, and NK cells, and have reduced macrophage and dendritic cell function. This study characterized the NCG mouse model for toxicity, engraftment and tumorigenicity assessments of cell therapies, using CD34⁺ hHSPC adult mobilized cells with two myeloablation regimens.Mice received sub-lethal irradiation or busulfan and were then injected intravenously with CD34⁺ hHSPCs (1.0 x 106 cells/mouse) or PBS (control), while positive control animals received 2 x 106 HL-60 cells/mouse. hCD34+ cell donors were treated with the mobilizing agent G-CSF prior to leukapheresis. Following injections, mouse blood samples were collected to assess engraftment rates by flow cytometry with body weights recorded periodically up to 20 weeks post-cell injection. No significant clinical signs or body weight changes were observed. At week 10 post-cell injection, the peripheral blood chimerism of hCD45+ cells was above 20%. While mCD45+ concentration was constant between week 10 and 17 in whole blood samples, hCD45+ concentration and chimerism slightly decreased at week 17. However, chimerism remained above 10%, with busulfan-treated mice presenting higher values. Chimerism was further assessed by quantifying human Alu sequences in blood and multiple organs using qPCR. Alu sequences were most abundant in the spleen and bone marrow, while lowest in the testes. In the positive control group, expected mortalities due to tumorigenesis were observed between days 27 and 40 post-cell injection. Overall, study results may be used to inform study design and potential toxicological endpoints relevant to non-clinical cell therapy development.

Impact of mobilization regimen on multiday collection of peripheral blood CD34+ cells by large volume leukapheresis

BACKGROUND

The collection yield of hematopoietic progenitors cell (HPC) by leukapheresis is critical for a successful transplantation, which often requires multiday collections to achieve the collection goal.

STUDY DESIGN AND METHODS

Collection procedures of 181 patients who underwent leukapheresis for more than 1 day were reviewed. Patients were separated into six groups based on the mobilization regimen: G-CSF on day 1 (D1) and day 2 (D2) (G-G); G-CSF on D1 and G-CSF and plerixafor on D2 (G-GP); G-CSF and plerixafor on day D1 and D2 (GP-GP); G-CSF and plerixafor on D1 and G-CSF on D2 (GP-G); chemotherapy and G-CSF on D1 and D2 (GC-GC); and chemotherapy, G-CSF, and plerixafor on D1 and D2 (GCP-GCP). Patient's pre-collection CD34 count (pre-CD34) on D1 and D2 were compared in the same individual and among groups.

RESULTS

We found D2 pre-CD34 were significantly decreased in G-G, GP-G, and GP-GP groups and significantly increased in G-GP group (p < .001) using a repeated measures ANOVA analysis. D2 pre-CD34 remained at similar levels as D1 in GC-GC and GCP-GCP groups. A multiple regression analysis showed that the mobilization regimen was the only factor that significantly affected pre-CD34 D2/D1 ratio (p < .001). There was a significant difference in the pre-CD34 D2/D1 ratio (p < .001) among these six groups with the lowest in GP-G group (0.40 ± 0.45), and the highest in G-GP group (2.35 ± 0.36).

DISCUSSION

Mobilization regimen has significant impact on pre-collection CD34 count. Apheresis facilities may change mobilizing drugs accordingly to achieve a specific HPC goal.

Outcomes of stem cell mobilization and engraftment in patients with multiple myeloma according to CD56 expression status

BACKGROUND

The molecular mechanism underlying the mobilization and engraftment of CD34+ cells is poorly understood. The most relevant factors in the regulation of stem cell release and engraftment include chemokines, adhesion molecules, and chemokine receptors. Previously, it was suggested that the absence of CD56 expression could be used as a predictive factor for mobilization failure at the time of diagnosis. Here, we investigated the effect of CD56 expression status on both mobilization and engraftment processes. Additionally, other factors affecting mobilization and engraftment efficacy were investigated.

METHODS

Data from 79 multiple myeloma patients undergoing autologous stem cell transplantation between 2015 and 2020 were analyzed for peripheral stem cell mobilization and posttransplant neutrophil and platelet engraftment according to CD56 expression on myeloma cells.

RESULTS

No difference in either the median number of CD34+ cells collected or time to engraftment was found between the CD56+ and CD56- groups. The age of the patients (p = 0.025) and peak number of circulating CD34+ cells in peripheral blood (p = 0.005) were important predictors for a higher number of collected CD34+ cells. The average time to recovery of leukocytes and platelets after transplantation was markedly correlated with the number of transplanted stem cells and peak number of circulating CD34+ cells in peripheral blood, respectively (p = 0.049 and p = 0.003).

CONCLUSIONS

Our results indicated no effect of CD56 expression status on the mobilization and engraftment of PBSCs. Our results also support the notion that the peak number of circulating CD34+ cells in peripheral blood is clinically important for rapid platelet engraftment following HPC transplantation.

Collection, cryopreservation and thawing of stem cells for children weighing less than 25 Kg with high-risk neuroblastoma: A single center results in Morocco

Introduction

An important component of the advances made in neuroblastoma treatment has been the use of peripheral blood stem cells to support high-dose chemotherapy. In this study, we report our experience on a series of small children who have undergone standard and large volume leukaphersis (LVL) procedures, provide an update on a single institution's experience with cryopreservation of autologous peripheral blood stem cells (PBSCs), using 10% dimethyl sulfoxide (DMSO) and applying post-thaw DMSO depletion and analyze a number of variables that may affect viability.

Methods

A total of 36 aphereses were performed on 29 children weighing less than 25 kg between July 2016 and October 2019 at the Ibn Sina university hospital.

Results

Seven females and twenty-two males, median bodyweight 14 kg (9 - 22). A single apheresis was sufficient to obtain at least 3 × 10⁶/kg body weight (BW) of CD34+ cells in 82.8% of the cases. The LVL was performed in 22 aphereses. A median number of 5.9 × 10⁶/kg CD34 cells were collected per apheresis. A total of 60 PBSC samples were cryopreserved and 46 samples were infused. The mean cell viability percentage decreased from 94.75 ± 1.14% before freezing to 70.84 ± 8.6% after thawing (p < 0.001). No correlation was found between post-thaw viability and storage time (r = -0.233; p = 0.234) or number of total nucleated cells (r = 0.344; p = 0.073).

Conclusion

Leukapheresis is safe and feasible in small pediatric patients if the appropriate measures are used. Cryopreservation poses numerous challenges, especially a decrease in cell viability after thawing.

Mobilized Peripheral Blood Stem Cells are Pluripotent and Can Be Safely Harvested and Stored for Cartilage Repair

PURPOSE

The primary objective of this study was to reproduce and validate the harvest, processing and storage of peripheral blood stem cells for a subsequent cartilage repair trial, evaluating safety, reliability, and potential to produce viable, sterile stem cells.

METHODS

Ten healthy subjects (aged 19-44 years) received 3 consecutive daily doses of filgrastim followed by an apheresis harvest of mononuclear cells on a fourth day. In a clean room, the apheresis product was prepared for cryopreservation and processed into 4 mL aliquots. Sterility and qualification testing were performed pre-processing and post-processing at multiple time points out to 2 years. Eight samples were shipped internationally to validate cell transport potential. One sample from all participants was cultured to test proliferative potential with colony forming unit (CFU) assay. Five samples, from 5 participants were tested for differentiation potential, including chondrogenic, adipogenic, osteogenic, endoderm, and ectoderm assays.

RESULTS

Fresh aliquots contained an average of 532.9 ± 166. × 10⁶ total viable cells/4 mL vial and 2.1 ± 1.0 × 10⁶ CD34+ cells/4 mL vial. After processing for cryopreservation, the average cell count decreased to 331.3 ± 79. × 10⁶ total viable cells /4 mL vial and 1.5 ± 0.7 × 10⁶ CD34+ cells/4 mL vial CD34+ cells. Preprocessing viability averaged 99% and postprocessing 88%. Viability remained constant after cryopreservation at all subsequent time points. All sterility testing was negative. All samples showed proliferative potential, with average CFU count 301.4 ± 63.9. All samples were pluripotent.

CONCLUSIONS

Peripheral blood stem cells are pluripotent and can be safely harvested/stored with filgrastim, apheresis, clean-room processing, and cryopreservation. These cells can be stored for 2 years and shipped without loss of viability.

CLINICAL RELEVANCE

This method represents an accessible stem cell therapy in development to augment cartilage repair.

Plerixafor strategies for autologous hematopoietic cell transplant mobilization: A comparison of efficacy and cost

Addition of plerixafor (P) to granulocyte colony stimulating factor (G-CSF) during peripheral blood mobilization of hematopoietic stem cells (HSC) increases the number of patients meeting collection goals prior to autologous stem cell transplant (aSCT). However, use of P is not universal among transplant centers due to cost. This study aims to compare clinical and financial impacts of using an algorithm-based P mobilization strategy versus use in all patients. This was a single center, retrospective analysis of adult patients with myeloma or amyloidosis receiving aSCT who received apheresis of their HSC between 3/1/2017 and 3/1/2019. Patients prior to 3/1/2018 were classified as receiving P "per algorithm" and those after this date were classified as "up-front" P. For the per-algorithm group, P was given for a pre-apheresis CD34+ cell count of <20 cells/μL on mobilization day 5 and patients returned on day 6 for apheresis. Of the 129 patients included, 55 received P per-algorithm and 74 received up-front P. There was a reduction in median number of apheresis days (1.5 vs 1 day, p < 0.001) and an increase in median number of CD34+ cells collected (6.6 vs 8.5 × 10⁶ cells/kg, p < 0.001) with up-front P. Up-front P increased drug cost but reduced apheresis costs, which resulted in a net savings of $121 per patient in total mobilization costs. These findings suggest that use of up-front P for mobilization significantly reduces apheresis days and increases HSC collection yield without increasing overall cost per patient.

Pulmonary hypertension associated with busulfan

Busulfan is widely used to treat malignant diseases, particularly for therapeutic intensification prior to an autologous stem cell graft. Numerous side effects consecutive to busulfan are described, but few descriptions of pulmonary hypertension exist, while bronchiolitis obliterans remains a rare complication. We report the clinical observations of four patients from the French Pulmonary Hypertension Registry who experienced subacute pulmonary hypertension after receiving busulfan as preparation regimen before an autologous stem cell graft for malignancies (Hodgkin's disease, Ewing's sarcoma and primary large B cell lymphoma of the brain). Patients experienced severe pulmonary arterial hypertension 2 to 4.5 months after busulfan administration. Pulmonary hypertension improved after treatment with approved drugs for pulmonary arterial hypertension and/or corticosteroids. During the follow-up period, two patients developed chronic respiratory insufficiency due to interstitial lung disease, leading to double lung transplantation. The pathological assessment of explanted lungs revealed interstitial lung fibrosis with advanced bronchiolar lesions and severe pulmonary vascular damage. Three of the four patients were still alive after 36 to 80 months and the fourth died unexpectedly and suddenly after 5 months. In conclusion, PAH is a rare but severe complication associated with busulfan chemotherapy in adults. Histological examinations provide evidence for diffuse pulmonary vascular damage combined with interstitial lung injury in most cases.

Peripheral blood stem and progenitor cell collection in pediatric candidates for ex vivo gene therapy: a 10-year series

Hematopoietic stem and progenitor cell (HSPC)-based gene therapy (GT) requires the collection of a large number of cells. While bone marrow (BM) is the most common source of HSPCs in pediatric donors, the collection of autologous peripheral blood stem cells (PBSCs) is an attractive alternative for GT. We present safety and efficacy data of a 10-year cohort of 45 pediatric patients who underwent PBSC collection for backup and/or purification of CD34⁺ cells for ex vivo gene transfer. Median age was 3.7 years and median weight 15.8 kg. After mobilization with lenograstim/plerixafor (n = 41) or lenograstim alone (n = 4) and 1−3 cycles of leukapheresis, median collection was 37 × 10⁶ CD34⁺ cells/kg. The procedures were well tolerated. Patients who collected ≥7 and ≥13 × 10⁶ CD34⁺ cells/kg in the first cycle had pre-apheresis circulating counts of at ≥42 and ≥86 CD34⁺ cells/μL, respectively. Weight-adjusted CD34⁺ cell yield was positively correlated with peripheral CD34⁺ cell counts and influenced by female gender, disease, and drug dosage. All patients received a GT product above the minimum target, ranging from 4 to 30.9 × 10⁶ CD34⁺ cells/kg. Pediatric PBSC collection compares well to BM harvest in terms of CD34⁺ cell yields for the purpose of GT, with a favorable safety profile.

The association of mobilising regimen on immune reconstitution and survival in myeloma patients treated with bortezomib, cyclophosphamide and dexamethasone induction followed by a melphalan autograft

G-CSF only mobilisation has been shown to enhance immune reconstitution early post-transplant, but its impact on survival remains uncertain. We undertook a retrospective review of 12 transplant centres to examine overall survival (OS) and time to next treatment (TTNT) following melphalan autograft according to mobilisation method (G-CSF only vs. G-CSF and cyclophosphamide [CY]) in myeloma patients uniformly treated with bortezomib, cyclophosphamide and dexamethasone induction. Six centres had a policy to use G-CSF alone and six to use G-CSF + CY. Patients failing G-CSF only mobilisation were excluded. 601 patients were included: 328: G-CSF + CY, 273: G-CSF only. Mobilisation arms were comparable in terms of age, Revised International Staging System (R-ISS) groups and post-transplant maintenance therapy. G-CSF + CY mobilisation generated higher median CD34 + yields (8.6 vs. 5.5 × 10⁶/kg, p < 0.001). G-CSF only mobilisation was associated with a significantly higher lymphocyte count at day 15 post-infusion (p < 0.001). G-CSF only mobilisation was associated with significantly improved OS (aHR = 0.60, 95%CI 0.39-0.92, p = 0.018) and TTNT (aHR = 0.77, 95%CI 0.60-0.97, p = 0.027), when adjusting for R-ISS, disease-response pre-transplant, age and post-transplant maintenance therapy. This survival benefit may reflect selection bias in excluding patients with unsuccessful G-CSF only mobilisation or may be due to enhanced autograft immune cell content and improved early immune reconstitution.

Peripheral blood stem cell mobilization with pegylated granulocyte colony stimulating factor in children

BACKGROUND AND AIM

We report here our experience of using pegylated granulocyte colony stimulating factor (peg-GCSF) for peripheral blood stem cell (PBSC) mobilization in children.

METHODS AND RESULTS

A total of nine children suffering from high-risk/relapsed solid tumors were mobilized with chemotherapy and peg-GCSF (100 microgram/kg single dose). Mean age was 7.7 years (range 2-15 years).The mean time from peg-GCSF administration to PBSC harvest was 9.7 days. Adequate stem cells (median dose 26.9 million/kg) could be harvested in all children by a single apheresis procedure. No major adverse events observed.

CONCLUSION

It is feasible and safe to mobilize PBSC with peg-GCSF in children with cancer.

Novel use of a midline catheter for therapeutic and donor apheresis in children and adults

BACKGROUND

Apheresis procedures require adequate vascular access to achieve optimal inlet flow rates. While central lines provide such access, their placement and use are associated with risks; some of these risks are minimized if peripheral intravenous access can be established. However, peripheral intravenous access is associated with challenges in the pediatric setting. Research indicates that midline catheters reduce the use of CVADs and their associated risks. The use of midline catheters for apheresis has been reported recently in adults, but no studies have been published on their use in children. Thus, the purpose of this study was to evaluate the use of midline catheters for apheresis in the pediatric setting.

METHODS

A retrospective observational study was conducted to evaluate the safety and efficacy of midline catheters in subjects who underwent apheresis at a pediatric hospital from April 2018 to August 2020. Demographic data, clinical data (diagnosis, procedure, catheter size, body mass), and outcome data (inlet flow rate, total blood volume [TBV] processed, procedure time, and cell counts) were collected.

RESULTS

Eighteen subjects received a total of 100 midline catheters for 73 apheresis procedures. Inlet flow rates ranged from 45 to 80 mL/min, TBV ranged from 2872 to 20 000 mL, and procedure time ranged from 1.25 to 7 hours. Inlet flow rates met or exceeded the recommended inlet flow rates for apheresis in children and adults (P < .0001). No adverse events occurred.

CONCLUSION

Midline catheters provide safe and effective vascular access for apheresis. Future research should include younger patients with lower body mass.

Successful autologous peripheral blood stem cell collection using large volume leukapheresis in patients with very low or undetectable peripheral blood CD34+ progenitor cells

Autologous stem cell transplantation provides some patients with hematolymphoid and solid organ malignancies an opportunity for cure. Management of peripheral hematopoietic stem cell (HSC) collections differs among institutions, especially if a very low pre-procedure peripheral blood CD34+ cell count (PBCD34) is demonstrated. This study retrospectively analyzed results of large-volume peripheral HSC collections in 91 patients over approximately two years. Fifteen patients with PBCD34 < 10 × 10e6/l (eleven with undetectable PBCD34) were compared to 76 patients with higher counts on the first collection day (adequate mobilizers). The poor mobilizer group had significantly lower pre-collection WBC and platelet counts as well as collection yields. However, most patients with PBCD34 < 10 × 10e6/l (80 %) collected the minimum target for HSC transplant (2.0 × 10e6 CD34+ cells/kg) in <5 consecutive days of collection, and those who did collect the minimum successfully underwent autologous transplantation, with hematopoietic engraftment and long-term survival comparable to the adequate mobilizers. Successful HSC collection may often be achieved regardless of d 1 PBCD34 counts.

Use of Backup Stem Cells for Stem Cell Boost and Second Transplant in Patients with Multiple Myeloma Undergoing Autologous Stem Cell Transplantation

Autologous hematopoietic stem cell transplantation (ASCT) is a standard treatment for multiple myeloma (MM). Consensus guidelines recommend collecting sufficient stem cells in case there is a need for stem cell boost for delayed/poor engraftment or for future second ASCT. However, collecting and storing backup stem cells in all patients requires significant resources and cost, and the rates of backup stem cell utilization are not well studied. We sought to examine the utilization of backup stem cells (BSCs) in patients with MM undergoing ASCT. Patients with MM aged ≥18 years old who underwent first ASCT at our institution from January 2010 through December 2015 and collected sufficient stem cells for at least 2 transplants were included in this single-center retrospective study. This timeframe was selected to allow for adequate follow-up. A total of 393 patients were included. The median age was 58 years (range, 25-73). After a median follow-up of 6 years, the median progression-free survival (PFS) of the cohort was 3 years. Sixty-one percent (n = 240) of patients progressed or relapsed. Chemotherapy-based mobilization was used in almost all patients (98%). The median total CD34+ cells collected was 18.2 × 106/kg (range, 3.4-112.4). A median of 5.7 × 106 CD34+ cells/kg (range, 1.8-41.9) was infused during the first ASCT, and a median of 10.1 × 106 CD34+ cells/kg (range, 1.5-104.5) was cryopreserved for future use. Of the patients, 6.9% (n = 27) used backup stem cells, with 2.3% (n = 10) using them for stem cell boost, 4.6% (n = 18) for a second salvage ASCT, including 1 patient for both stem cell boost and second ASCT. Rates of backup stem cell use among patients aged <60, 60-69, and ≥70 years were 7.8%, 5.7%, and 5.9%, respectively. There was a trend toward higher rates of backup stem cell use for second ASCT in patients who were younger, had suboptimal disease control at time of first ASCT, and longer PFS. The median dose of stem cell boost given was 5.6 × 106 CD34+ cells/kg (range, 1.9-20). The median time from stem cell boost to neutrophil, hemoglobin, and platelet engraftment was 4 (range, 2-11), 15 (range, 4-34), and 12 (range, 0-34) days, respectively. Lower CD34+ dose and older age at time of ASCT predicted need for stem cell boost. With new salvage therapies for relapsed MM, the rates of second ASCT are very low. The low rates of use suggest that institutional policies regarding universal BSC collection and long-term storage should be reassessed and individualized. However, need for stem cell boost in 2.3% of patients may present a challenge to that.

Real World Clinical Experience of Biosimilar G-CSF (Grastofil) for Autologous Peripheral Blood Stem Cell Mobilization: Single Center Experience in Canada Following Early Adoption

Introduction: Granulocyte colony-stimulating factor (G-CSF) is the first line treatment for mobilization, most commonly using a regimen of daily filgrastim. The use of biosimilars can provide substantial cost savings to the health care system while delivering comparable efficacy outcomes. In 2016, the Saskatchewan Cancer Agency was a leader in Canada, instituting formulary changed from a G-CSF originator product to a cost savings alternative biosimilar for stem cell mobilization prior to autologous stem cell transplant (ASCT) and for engraftment. The purpose of this study was to investigate the clinical comparability of biosimilar G-CSF to its reference product in a real-world clinical setting and to validate use of the biosimilar in mobilization and engraftment-an indication which had been granted by extrapolation.

METHODS

A retrospective chart review was completed including all patients diagnosed with a hematological malignancy between 2012 and 2018 who underwent ASCT. To assess real-world outcomes across a diverse population, successful CD34+ stem cell collection was compared between patients mobilized with originator filgrastim, Neupogen, and biosimilar filgrastim, Grastofil. Additional comparisons included the number of apheresis required, time to absolute neutrophil count (ANC) engraftment, platelet engraftment, length of hospital stay, and Plerixafor use.

RESULTS

217 patients were mobilized and transplanted during the study period. There was no statistically significant difference in success rate between patients mobilized with biosimilar filgrastim and those who had received originator G-CSF (100% vs. 92.4%, p = 0.075). Neither disease type, nor concurrent chemomobilization regimen resulted in a detectable difference between the two G-CSF products in successful stem cell harvest. Engraftment was highly similar between groups, as demonstrated by ANC recovery (11.6 days Neupogen vs. 11.6 days Grastofil), platelet recovery (14.0 days Neupogen vs. 14.2 days Grastofil), and total length of hospital stay (22.4 days Neupogen vs. 22.3 days Grastofil). No statistically significant difference in adjunctive use of Plerixafor^® was observed between Neupogen and Grastofil patients (25.9% vs. 23.4%, p = 0.72).

CONCLUSION

Extrapolation of indications for biosimilars is justified. This real-world evidence builds upon registrational studies to confirm that no clinically meaningful differences were detected between originator Neupogen and biosimilar Grastofil in the setting of PBSC mobilization and engraftment post ASCT. Biosimilars are as safe and effective as originator products. Implementation across all approved indications without hesitation maximizes cost savings to the provincial system, allowing for more optimal allocation of health care resources.

Lenograstim versus filgrastim in mobilization before autologous hematopoietic stem cell transplantation in patients with multiple myeloma and lymphoma - Single center experience

OBJECTIVE

Peripheral blood stem cell transplantation is frequently used in the treatment of various hematological malignancies after intensive chemotherapy. The primary aim of our study is to compare the amount of collected CD34+ cells and engraftment times in patients mobilized with filgrastim or lenograstim.

MATERIAL AND METHODS

Demographic and clinical data of multiple myeloma (MM) and lymphoma patients who underwent autologous transplantation and mobilized with G-CSF (filgrastim or lenograstim) without chemotherapy were collected retrospectively.

RESULTS

One hundred eleven MM and 58 lymphoma patients were included in the study. When mobilization with filgrastim and lenograstim was compared in MM patients, there was no significant difference in neutrophil and thrombocyte engraftment times of lenograstim and filgrastim groups (p = 0.931 p = 0.135, respectively). Similarly, the median number of CD34+ cells collected in patients receiving filgrastim and lenograstim was very similar (4.2 × 10⁶/kg vs 4.3 × 10⁶/kg, p = 0.977). When compared with patients who received lenalidomide before transplantation and patients who did not receive lenalidomide, the CD34+ counts of the two groups were similar. However, neutrophil and platelet engraftment times in the group not receiving lenalidomide tended to be shorter (p = 0.095 and p = 0.12, respectively). When lymphoma patients mobilized with filgrastim and lenograstim were compared, neutrophil engraftment time (p = 0.498), thrombocyte engraftment time (p = 0.184), collected CD34+ cell counts (p = 0.179) and mobilization success (p = 0.161) of the groups mobilized with filgrastim and lenograstim were similar.

CONCLUSION

The superiority of the two agents to each other could not be demonstrated. Multi-center prospective studies with larger numbers of patients are needed.

Cost saving, patient centered algorithm for progenitor cell mobilization for autologous hematopoietic cell transplantation

Administration of plerixafor with granulocyte-colony stimulating factor (G-CSF) mobilizes CD34+ cells much more effectively than G-CSF alone, but cost generally limits plerixafor use to patients at high risk of insufficient CD34+ cell collection based on low peripheral blood (PB) CD34+ counts following 4 days of G-CSF. We analyzed costs associated with administering plerixafor to patients with higher day 4 CD34+ cell counts to decrease apheresis days and explored the use of a fixed split dose of plerixafor instead of weight-based dosing. We analyzed 235 patients with plasma cell disorders or non-Hodgkin's lymphoma who underwent progenitor cell mobilization and autologous hematopoietic cell transplantation (AHCT) between March 2014 and December 2017. Two hundred ten (89%) received G-CSF plus Plerixafor and 25 (11%) received G-CSF alone. Overall, 180 patients (77%) collected in 1 day, 53 (22%) in 2 days and 2 (1%) in 3 days. Based on our data, we present a probabilistic algorithm to identify patients likely to require more than one day of collection using G-CSF alone. CD34+ cell yield, ANC and platelet recovery were not significantly different between fixed and standard dose plerixafor. Plerixafor enabled collection in 1 day and with estimated savings of $5000, compared to patients who did not receive plerixafor and required collection for three days. While collection and processing costs and patient populations vary among institutions, our results suggest re-evaluation of current algorithms.

[Analysis of the efficacy and safety of plerixafor combined with G-CSF in plasma cell disease mobilization]

目的

分析普乐沙福联合G-CSF在浆细胞疾病自体造血干细胞中动员的效果及安全性。

方法

回顾性分析2018年1月至2019年12月在北京大学人民医院使用普乐沙福联合G-CSF进行自体造血干细胞动员的浆细胞疾病患者的基线临床资料、采集成功率及不良反应。

结果

共纳入49例浆细胞疾病患者，多发性骨髓瘤（MM）39例（79.6%），淀粉样变性8例（16.3%），肾脏意义的单克隆免疫球蛋白沉积病（MGRS）2例（4.1%），肾功能不全16例（32.7%）。其他动员方案既往采集失败患者7例（14.3%）。使用普乐沙福动员后，中位采集次数1（1～3）次，中位采集天数2（1～3）d，一次采集成功47例（95.9%），两次采集累积成功率为100%。在16例肾功能不全的患者中，5例（31.3%）患者第1天采集成功，8例（50%）需要第2天采集，3例（18.8%）需要第3天采集。主要不良反应依次为乏力、失眠、腹痛、腹泻、头晕、关节痛。共37例患者行auto-HSCT，白细胞中位植活时间11（8～13）d，血小板中位植活时间11（9～26）d。

结论

普乐沙福联合G-CSF用于浆细胞疾病患者自体造血干细胞动员成功率高，不良反应少，即使在肾功能不全的患者中也具有较高的动员成功率。

Autologous Bone-Marrow vs. Peripheral Blood Mononuclear Cells Therapy for Peripheral Artery Disease in Diabetic Patients

Diabetes mellitus (DM) remains one of the most important risk factors for peripheral artery disease (PAD), with approximately 20% of DM patients older than 40 years old are affected with PAD. The current standard management for severe PAD is endovascular intervention with or without surgical bypass. Unfortunately, up to 40% of patients are unable to undergo these revascularization therapies due to excessive surgical risk or adverse vascular side effects. Stem cell therapy has emerged as a novel therapeutic strategy for these ‘no-option’ patients. Several types of stem cells are utilized for PAD therapy, including bone marrow mononuclear cells (BMMNC) and peripheral blood mononuclear cells (PBMNC). Many studies have reported the safety of BMMNC and PBMNC, as well as its efficacy in reducing ischemic pain, ulcer size, pain-free walking distance, ankle-brachial index (ABI), and transcutaneous oxygen pressure (TcPO2). However, the capacity to establish the efficacy of reducing major amputation rates, amputation free survival, and all-cause mortality is limited, as shown by several randomized placebo-controlled trials. The present literature review will focus on comparing safety and efficacy between BMMNC and PBMNC as cell-based management in diabetic patients with PAD who are not suitable for revascularization therapy.

Plerixafor combined with G-CSF for stem cell mobilization in children qualified for autologous transplantation- single center experience

Failure of autologous peripheral blood CD34⁺ stem cells collection can adversely affect the treatment modality for patients with hematological and nonhematological malignant diseases where high dose chemotherapy followed by hematopoietic stem cell transplantation has become part of their treatment. Plerixafor in conjunction with G-CSF is approved for clinical use as a mobilization agent. The clinical efficacy of Plerixafor in CD34⁺ cells collection was analyzed in our institution. A total of 13 patients aged 1-15,5 years received Plerixafor in combination with G-CSF: 7 with neuroblastoma, 2 with Ewing's sarcoma and single patients with Hodgkin's lymphoma, germ cell tumor, retinoblastoma and Wilms tumor. Twelve patients (923%) achieved CD34+ cell counts of ≥ 20 × 10⁶/L after 1-7 doses of Plerixafor. The average 9,9 - fold increase in number of CD34⁺ cells were achieved following the first dose and 429 - fold after second dose of plerixafor. Among the 13 patients, 12 yielded the minimum required cell collection of 2 × 10⁶/kg within an average of 2 doses of Plerixafor. The mean number of apheresis days was 1.75. The median total number of collected CD34⁺ cells was 982 × 10⁶/kg. Plerixafor enables rapid and effective mobilization, and collection of sufficient number of CD34⁺ cells.

Optimization of repeat plerixafor dosing for autologous peripheral blood stem-cell collection

INTRODUCTION

Peripheral CD34+ cells may be mobilized using filgrastim alone or in combination with chemotherapy. The addition of plerixafor can be efficacious, though guidelines for repeat dosing are lacking.

MATERIAL AND METHODS

This quality improvement project was initiated to generate guidelines for repeat plerixafor dosing after retrospective evaluation of data in adult patients undergoing autologous peripheral blood stem cell mobilization and collection.

RESULTS

Analysis included 195 patients: 119 (61 %) with multiple myeloma and 76 (39 %) with lymphoma. Patients given at least one dose of plerixafor (n = 109) were further divided: Group 1) (A) goal of 3 × 10E6/kg and day 1 peripheral blood CD34+ count < 30 × 10E6/L, vs (B) ≥ 30 × 10 E6/L; Group 2) (A) goal of 6 × 10E6/kg and day 1 peripheral blood CD34+ count < 50 × 10E6/L or < 50 % of collection goal after day 1, vs (B) ≥ 50 % of collection goal after day 1. Ninety five percent of cases in Group 1B and 88 % of cases in Group 2B did not receive additional plerixafor doses and all of them achieved their collection goals. In contrast, those in Groups 1A and 2A required additional plerixafor dosing and some mobilizations/collections were futile.

CONCLUSION

Based on these data, with consideration of collection goal, peripheral blood CD34+ count, and CD34+ cell bag count on collection day 1, we have generated institutional guidelines for collection initiation and repeat plerixafor dosing. Long term, we predict these guidelines will optimize pharmacy, apheresis, and stem cell processing resources while improving the patient experience.

YF-H-2015005, a CXCR4 Antagonist, for the Mobilization of Hematopoietic Stem Cells in Non-Hodgkin Lymphoma Patients: A Randomized, Controlled, Phase 3 Clinical Trial

Background: YF-H-2015005, a novel CXCR4 antagonist, has been proven to increase the quantities of circulating hematopoietic stem cells (HSCs), which results in an adequate collection of HSCs in non-Hodgkin lymphoma (NHL) patients.

Methods: This was a multicenter, double-blind, randomized (1:1), placebo-controlled phase III clinical trial. All patients received granulocyte colony-stimulating factor (G-CSF) for up to 8 consecutive days. YF-H-2015005 or placebo was administrated on the evening of day 4 and continued daily for up to 4 days. Apheresis was conducted 9–10 h after each dose of YF-H-2015005 or placebo. The primary endpoint was the proportion of NHL patients procuring ≥5 × 10⁶/kg CD34⁺ HSCs within ≤4 apheresis sessions.

Results: In total, 101 patients with NHL were enrolled. The proportions of patients achieving primary endpoint were 57 and 12% in YF-H-2015005 and placebo groups, respectively (P < 0.001). Moreover, a higher proportion of YF-H-2015005-treated patients reached a minimum target collection of ≥2 × 10⁶/kg CD34⁺ HSCs in ≤4 apheresis days compared to placebo-treated patients (86 vs. 38%, P < 0.001). Furthermore, the median time to collect ≥2 or 5 × 10⁶/kg CD34+ HSCs were 1 and 3 days in YF-H-2015005-treated patients, but 4 days and not reached in placebo-treated patients, respectively. No severe treatment emergent adverse events were observed in both YF-H-2015005 treatment and placebo groups.

Conclusions: YF-H-2015005 plus G-CSF regimen was a tolerable combination with high efficacy, which might be used to rapidly mobilize and collect HSCs in NHL patients.

Low-Dose Cyclophosphamide versus Intermediate-High-Dose Cyclophosphamide versus Granulocyte Colony-Stimulating Factor Alone for Stem Cell Mobilization in Multiple Myeloma in the Era of Novel Agents: A Multicenter Retrospective Study

The optimal stem cell (SC) mobilization strategy for patients with multiple myeloma (MM) remains a matter of debate. Possible approaches include low or high doses of cyclophosphamide (Cy), other chemotherapeutic agents, or granulocyte colony-stimulating factor (G-CSF) alone. The scope of the study was to compare low-dose Cy plus G-CSF versus intermediate-high-dose Cy plus G-CSF versus G-CSF alone for SC mobilization in MM, in terms of efficacy and safety. We retrospectively analyzed 422 MM patients undergoing SC mobilization in 6 Italian centers, including 188 patients who received low-dose Cy (LD-Cy group, defined as 2 g/m²), 163 patients who received intermediate-high-dose Cy (HD-Cy group, defined as ≥ 3 g/m²), and 71 patients who received G-CSF alone (G-CSF group). The median peak of circulating CD34+ cells was 77/µL in the LD-Cy group, 92/µL in the HD-Cy group, and 55/µL in the G-CSF group (P = .0001). The median amount of SCs collected was 9.1 × 10⁶/kg, 9.7 × 10⁶/kg, and 5.6 × 10⁶/kg in the 3 groups, respectively (P = .0001). The rate of mobilization failure (defined as failure to collect ≥2 × 10⁶/kg) was 3.7% in the LD-Cy group, 3.4% in the HD-Cy group, and 4.3% in the G-CSF group (P = .9). The target SC dose of at least 4 × 10⁶/kg was reached in 90.4%, 91.1%, and 78.6% of the patients in these 3 groups, respectively (P = .014). The "on demand" use of plerixafor was higher in the G-CSF group (76%) compared with the LD-Cy group (19%) and the HD-Cy group (6%). In multivariate analysis, G-CSF mobilization and previous use of melphalan or radiotherapy were independently associated with failure to collect the target SC dose of ≥4 × 10⁶/kg. No impacts of age, blood counts, or previous treatment with lenalidomide, bortezomib, or carfilzomib were observed. Our results suggest that LD-Cy may be considered for successful SC mobilization in patients with MM.