Peripheral Blood Stem Cell Mobilization Research Articles

Autologous peripheral blood stem cell mobilization and apheresis in pediatric patients with cancer: A single-center report of 64 procedures.

The published experience concerning autologous peripheral blood stem cell collection in children is very limited. The data of pediatric patients who underwent autologous stem cell mobilization and apheresis between January 2011 and April 2020 were analyzed retrospectively. We studied retrospectively 64 mobilization and apheresis procedures in 48 pediatric patients (34 males, 14 females), mean age of 7.31 ± 5.38 (range, 1.5-19.7) years, the underlying disease was mostly neuroblastoma (NBL). The body weight of 21 patients (43.75%) was 15 kg or less. The targeted autologous peripheral stem cell apheresis (APSCA) was successfully achieved in 98% of patients. Neuroblastoma patients were younger than the rest of the patients and underwent apheresis after receiving fewer chemotherapy cycles than others and all of them mobilized within the first session successfully. Plerixafor was added to mobilization in nine heavily pretreated patients (18.7%), median two doses (range, 1-4 doses). 11 patients (22.9%) underwent radiotherapy (RT) before mobilization with doses of median 24 Gy (range, 10.8-54.0 Gy). Patients with RT were older at the time of apheresis and had received more chemotherapy courses than patients without RT. As a result, patients with a history of RT had significantly lower peripheral CD34+ cells and CD34+ yields than those without RT. In 17 patients (35.4%), 22 different complications were noted. The most common complications were catheter-related infections (n:10, 20.8%), followed by catheter-related thrombosis in eight patients (16.7%). Patients who had far less therapy before apheresis were more likely to mobilize successfully. Our study provides a detailed practice approach including complications during APSCA aiming to increase the success rates of apheresis in transplantation centers.

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

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. 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. 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. 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).

Efficacy of prophylactic antibiotics for the prevention of neutropenic fever in patients with multiple myeloma receiving high-dose cyclophosphamide for stem cell mobilization

High-dose cyclophosphamide (HD-Cy) (3 g/m2) plus granulocyte colony-stimulating factor (G-CSF) is a very effective regimen for peripheral blood stem cell (PBSC) mobilization. Unfortunately, it is associated with an increased risk of neutropenic fever (NF). We analyzed the effect of NF on PBSC apheresis results and the efficacy of prophylactic antibiotics for the prevention of NF associated with HD-Cy plus G-CSF for PBSC mobilization in patients with newly diagnosed multiple myeloma (MM). First, patients were divided into NF ( +) and NF ( −) groups according to whether they suffered from NF during mobilization. Second, we divided patients into an antibiotic prophylaxis group and a nonantibiotic prophylaxis group according to whether antibiotic prophylaxis was used during the mobilization period. Our study showed that NF( +) patients (n = 44) had lower CD34 + cell dose collection (median 2.60 versus 5.34 × 106/kg, P < 0.001) and slower neutrophil engraftment and platelet engraftment (median 11 versus 10 days, P = 0.002, and median 13 versus 11 days, P = 0.043, respectively) than NF( −) patients (n = 234). Of note, the nonantibiotic prophylaxis group patients (n = 30) had a 26.7% incidence of NF. In the patients receiving antibiotic prophylaxis (n = 227), the incidence was reduced to 9.3% (P = 0.01). The antibiotic prophylaxis patients had higher CD34 + cell collection (median 5.41 versus 2.27 × 106/kg, P < 0.001) and lower hospitalization cost of mobilization ($ median 3108.02 versus 3702.39, p = 0.012). Thus, our results demonstrate that NF is associated with lower CD34 + cell collection and that antibiotic prophylaxis can reduce the incidence of NF and improve stem cell mobilization and collection outcomes, which reduces the hospitalization cost of mobilization.

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

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

PLERIXAFOR FOR HEALTHY PERIPHERAL BLOOD HEMATOPOIETIC STEM CELL DONORS IN PEDIATRIC ALLOGENEIC HSCT.

Data on use of plerixafor for peripheral blood stem cell(PBSC) mobilization in children with cancer undergoing autologous hematopoietic stem cell transplantation(HSCT) is there in literature. The use of plerixafor for normal healthy allogeneic donors is not reported much, especially in the pediatric setting. In this retrospective analysis from a single tertiary care centre in India, we report the efficacy and safety of the use of plerixafor in five healthy allogeneic PB-HSC donors and compare the outcomes with five others allogeneic HSCT’s in which plerixafor was not used. Ten allogeneic HSCT were included in the analysis, 5 in which the donor received plerixafor and in the other five the donor did not get it. In all the HSCT, PB HSC were the product.&#x0D; No significant difference in terms of recipients age and weight; donors age and weight and the CD- 34 count in PB before plerixafor were there between the two groups. However, the CD-34 HSC count in the harvested product was significantly higher in the group that received plerixafor (p=0.032). The stem cell dose transfused to the patient was also higher when the donor got plerixafor, although the difference was not significant. None of the donors suffered any side effects and underwent the subsequent apheresis uneventfully.&#x0D; The use of plerixafor in healthy stem cell donors (both pediatric and adult) for allogeneic stem cell transplant allowed a better yield of stem cells. In our experience the use of plerixafor was safe for the donors.

Peripheral blood stem cells mobilization in patients with relapsed or refractory lymphomas: A single-center experience

ABSTRACT Context: High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (AHSCT) is an established treatment for chemosensitive patients with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL). Aims: We present the results of using different salvage chemotherapy plus granulocyte colony stimulating factor (G-CSF) for mobilization of peripheral blood stem cells in R/R lymphoma patients. Subjects and Methods: For salvage chemotherapy, 93 patients received platinum-containing regimens, 4 patients received cytarabine-containing regimens, and 5 patients received other regimens. Patient distributions were HL (n = 35) and NHL (n = 67). Results: In 87.2% of patients, first mobilization trial was successful (&gt;2 × 106 CD34+ cells/kg). In 58.8% of patients, first apheresis season &gt;5 × 106 CD34+ cells/kg collections was achieved. All 12.7% of patients were poorly mobilized at the first mobilization. There was no statistical difference between the previous chemotherapy numbers and failed mobilization (P &gt; 0.05). Five patients who were poorly mobilized and 4 patients who were successfully mobilized underwent a previous radiotherapy (P &lt; 0.05). Thirteen patients who were poorly mobilized in the first mobilization underwent a platinum-containing salvage regimen. At the time of the first mobilization, the average peripheral CD 34 counts in the successfully mobilized group were statistically higher than that in the poorly mobilized group (P &lt; 0.01). Conclusions: We demonstrated that peripheral CD 34 cell count in the peripheral blood on the first apheresis day was a significant factor for more stem cell mobilization, fewer apheresis sessions, less volume, and earlier neutrophil engraftment for patients with R/R lymphoma and eligible for AHSCT. The history of the previous radiotherapy was a significant factor for poor mobilization.

Prolonged infusion time of cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) as a mobilization regimen may improve mobilization efficiency in newly diagnosed multiple myeloma patients: a single center experience

Objectives This study aimed to clarify the effectiveness and safety of two different infusion durations of cyclophosphamide (CTX) plus granulocyte colony-stimulating factor (G-CSF) for peripheral blood stem cell mobilization in patients with newly diagnosed multiple myeloma (NDMM). Methods One hundred and fifty-six consecutive NDMM patients receiving CTX plus G-CSF mobilization and autologous stem cell transplantation during the period of September 2008 to May 2020 were selected for retrospective analysis. According to differences in prolonged infusion time of CTX, they were divided into a 24-h group (24-h continuous infusion) and a control group (4-6 h of infusion). Mobilization and safety of infusion were analyzed. Flow cytometry was used to detect the peripheral blood CD34+ cell count. Multivariate analysis was performed to determine the factors influencing the number of CD34+ cells. Results The mean CD34+ cell counts collected in 24-h and control groups were 6.78 (interquartile range [IQR] 3.59-11.69) and 4.48 (IQR 2.39-6.30) ×106/kg, respectively (p < 0.001). Meanwhile, the target number of CD34+ cells/kg (defined as ≥4 × 106/kg) was collected from 51 (75%) of cases in 24-h group vs. 45 (51%) in the control group (p = 0.002). Multivariate analysis identified the independence of CTX infusion time as a factor influencing the target number of CD34+ cells/kg [odds ratio OR, 4.045; 95% CI: 1.630-10.038, p = 0.003]. The post-transplantation time to neutrophil engraftment was 10 (IQR 9-11) in 24-h group and 11 (IQR 10-12) in control group (p < 0.001). Finally, no statistical differences were identified between groups in terms of hematologic and non-hematologic toxicities. Conclusions For patients with NDMM, 24-h continuous infusion of CTX plus G-CSF contributes to improved mobilization efficiency and equivalent toxicity as a stem cell mobilization regimen.

Efficacy and Safty of Stem Cell Mobilization with Etoposide +Cytarabine Plus G-CSF in Patients with Lymphoma at High-Risk of Mobilizing Failure

Objective：Sufficient peripheral blood stem cell (PBSC) mobilization is important for performing successful autologous stem cell transplantation (ASCT) in patients with lymphoma. However, the optimal mobilization strategy remains a matter of debate in lymphoma.The aim of the study was to explore efficacy and safety of PBSC mobilization using etoposide combined with Cytarabine (EA) plus G-CSF in patients with lymphoma at high-risk of mobilizing failure. Methods：This retrospective study explored efficacy and safety of PBSC mobilization using EA (etoposide 50~100 mg/m2 , qd d1~3; AraC 0.5 g/m2 , q12h d1~3) plus G-CSF (5 µg/kg/day, from d5 until the day of apheresis) in 81 patients with lymphoma at high-risk of mobilizing failure. As previously reported, patients were defined at high-risk of mobilizing failure if (i) previous collection attempts failed (no special instructions); (ii) previous extensive radiotherapy or a complete course of treatment had affected stem cell activity; or (iii) any of these conditions: advanced disease (2 lines of chemotherapy), refractory disease, extensive bone marrow involvement or cellularity &amp;lt;30% at the time of mobilization or age 65 years. Results：The mean total and first apheresis trial CD34+ cells collection was 20.37(range 1.08~138.96) and 18.56(range 0.1~138.96)×10^6 CD34+ cells/kg, respectively. Overall, 79(97.5%) patents harvested adequate mobilization (≥2×10^6 CD34+ cells/kg), while 65(80.2%) patients achieved optimal mobilization(≥5×10^6 CD34+ cells/kg). A single apheresis was sufficient to reached the target yield of adequate apheresis in 67(82.7%) patients on median 15th day (range 11~19). We observed acceptable hematological toxicity and exposure of antibiotic usage in 57 patients with a median of 4 days. No severe infections or mobilization-related mortality were observed. Conclusion：Our resluts suggest that EA plus G-CSF is an effective and safe PBSC mobilization strategy for patients with lymphoma, including those predicted as poor mobilizers. The outcome should be evaluated in a randomized study.

Comparison of Biosimilar Filgrastim (Nivestym) Versus Originator Filgrastim (Neupogen) for Peripheral Blood Stem Cell Mobilization for Allogeneic Hematopoietic Stem Cell Transplantation

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is an optimal and potentially curative therapy for patients with hematologic malignancies. Granulocyte colony-stimulating factor (G-CSF) is used for the mobilization of peripheral blood stem cells (PBSCs) in allogeneic donors, and an optimal CD34 cell dose plays a critical role in successful transplantation. Nivestym, a biosimilar G-CSF to the originator Filgrastim (Neupogen), is now used by multiple institutions as it has become more available; however, there is a lack of data in this regard among healthy donors for allogeneic HSCT mobilization. In this study, we aim to compare the efficacy of Nivestym compared to Neupogen for allogeneic donor PBSC mobilization. Methods: For this retrospective single-center study, we included all (n=541) adult allogeneic HSCT donors at the University of Kansas Medical Center receiving Nivestym (January 2013-July 2020) or Neupogen (July 2020-June 2023) for donor PBSC mobilization. We conducted a bivariate analysis utilizing the ANOVA test. Statistical analyses were performed using SPSS version 28. Statistical significance was determined at p&amp;lt;0.05. Results: Our study included 541 allogeneic HSCT donors who received Neupogen (n=345, 64%) or Nivestym (n=196, 36%) for PBSC mobilization. The median age was 47 (range 17-76) years. The median donor weight was 86 (95% CI 87-91) kilograms. Donors receiving Neupogen had similar pre-GCSF WBC count (median 45 vs 47 K/uL, p=0.739), pre-GCSF CD34 percentages (median 17% vs 17%, p=0.527), and pre-GCSF circulating CD34 count (median 74 vs 74 million cells/kg, p=0.842) compared to donors receiving Nivestym. Neupogen recipients had similar median PBSC product total neutrophil count (TNC, 6.8 vs 6.5 K/uL, p=0.347), product CD34 percentage (75% vs 79%, p=0.068), absolute CD34 count (503 vs 533 million cells, p=0.636), and final CD34 dose (6.1 vs 6.3 million cells/kg, p=0.365) compared to Nivestym recipients. Seven percent (n=28) of donors needed two days of PBSC collection to achieve the target PBSC dose, with a statistically similar proportion noted in Neupogen (n=25, 7.3%) and Nivestym (n=13, 6.6%) cohorts. In a subgroup analysis stratified by age, donors aged 35 or older (n=154) had similar responses in all mentioned variables (p&amp;gt;0.05); however, for donors under the age of 35 years, the CD34 dose was higher in donors receiving Neupogen compared to Nivestym (median 6.9 vs 6.3 million cells/kg, p=0.044). Most of the PBSC collections (98%) were completed in one day, except for five donors in both Neupogen (5%) and Nivestym (8.5%) cohorts. Conclusions: Biosimilar G-CSF (Nivestym) demonstrated similar efficacy for peripheral blood stem cell mobilization compared to the originator G-CSF (Neupogen) among allogeneic HSCT donors. In donors aged 35 years or younger, a slightly lower PBSC product CD34 count was noted with Nivestym compared to Neupogen.

Assessment of Transduction of CD34+ Human Hematopoietic Stem Cells from Patients with Severe Hemophilia-Α with Lentiviral Vector Carrying a High Expression FVIII Transgene (CD68-ET3-LV)

Background: Alternative strategies are needed for the large number of people with hemophilia who are ineligible for AAV based gene therapy due to age or high levels of anti-AAV neutralizing antibodies. High inter-individual variability of expression and ill sustained factor levels are also challenges with AAV based gene therapy for hemophilia A, in particular. We have developed a third-generation lentiviral vector mediated hematopoietic stem cell-based gene therapy for hemophilia A. (Doering et al Human Gene Therapy 2018; 29: 1183-1201) This vector (CD68-ET3-LV) has a high expression FVIII transgene with a CD68 promoter targeting expression in monocytic cells predominantly. We report here successful transduction of severe hemophilia A patient derived human hematopoietic stem cells with this vector. Methods: Mobilized peripheral blood stem cells were collected by apheresis from three patients with severe hemophilia A without inhibitors who also received prophylactic clotting factor replacement therapy during this period. CD34+ hematopoietic stem cells (HSCs) were enriched on the CliniMACS Plus® system (Miltenyi Biotec, Bergish Gladbach, Germany) using the CliniMACS CD34® reagent system. Purified HSC were then transduced with this CD68-ET3-LV as follows - HSCs cultured on retronectin coated surfaces in xenofree media with cytokines were exposed to clinical grade CD68-ET3-LV vector in two ways - a double transduction protocol without any enhancer and a single transduction with an enhancer. After completion of this step, the product was assessed for viability and vector copy number (VCN) by trypan blue labelling and Q-PCR performed on genomic DNA from CFU cells, respectively. Transduced HSCs were also assessed for their engraftment potential. CD68-ET3-LV vector transduced HSC (1x10 6) were transplanted into NBSGW mice via tail vein injection. Engraftment was assessed at 16 weeks after transplantation. This protocol was approved by the Institutional Review Board of the Christian Medical College, Vellore, India. Results: G-CSF (10 ug/kg/day) based peripheral blood stem cell mobilization was well tolerated by all participants. The apheresis procedures which were done with plasma FVIII levels in the normal range after prophylactic replacement therapy were unremarkable. The total collection of mobilized CD34+ cells from the three donors was 268±80.5x10 6 CD34+ cells. An aliquot of 2x10 6 CD34+ cells/ml was used in the transduction experiments. The data on viability and vector copy number post transduction shown in the tables 1 and 2 confirm that viability was not affected by the manipulation of these HSCs in both double and single transduction methods. The vector copy number (VCN) in the genomic DNA obtained from CFU cells collected from CD34+ HSCs cultured in MethoCult H4434™ (Stem Cell Technologies™, Vancouver, Canada) varied from 0.62 to 1.21 in double transduction (n=3) and nearly doubled in the single transduction method with an enhancer to VCNs of 1.5 and 2.4 in two samples tested. Transplantation studies in NBSGW mice showed successful engraftment of human CD34+ HSCs with a mean engraftment of 80.99 ± 4.2% of CD45+ multilineage hematopoietic cells in the bone marrow 16 weeks after transplantation. Conclusion: To the best of our knowledge, this is the first report of transduction of mobilized peripheral blood CD34+ HSCs from patients with severe hemophilia A using a clinical grade lentiviral vector with a high expression FVIII transgene. These data establish feasibility and safety of the procedure. The transduction protocol showed good efficiency with very high viability, significant VCN and good engraftment of these gene modified human HSCs in a mouse model. These protocols are currently being evaluated in a first in human phase 1 clinical trial of gene therapy for severe hemophilia A without inhibitors.

Improving the Utilization and Tolerability of Thiotepa-Based Autologous Stem Cell Transplantation in Primary CNS Lymphoma

Background: Thiotepa-based autologous stem cell transplantation (ASCT) improves survival in primary central nervous system lymphoma (PCNSL) but up to 30-60% of patients are unable to receive ASCT after MATRix induction, frequently due to treatment-related adverse events. Common conditioning regimens such as thiotepa/BCNU or thiotepa/busulfan/cyclophosphamide have also been associated with risks of pulmonary toxicity or increased transplant-related mortality. Novel strategies to improve the utilization and tolerability of ASCT are therefore needed to maximize the curative potential of this therapy in PCNSL. Methods: This retrospective population-based study included all patients diagnosed with large B-cell lymphoma-type PCNSL who were intended for ASCT in the province of Alberta, Canada between 2011 and 2022. Provincial treatment guidelines recommended an abbreviated, low-intensity induction protocol to reduce toxicity and increase transplantation rates (Figure 1B). Step 1 included 2 cycles of rituximab/high-dose methotrexate (HD-MTX). Step 2 involved 1 cycle of rituximab/high-dose cytarabine (HDAC) for peripheral blood stem cell mobilization. Step 3 consisted of 2 cycles of rituximab/HD-MTX/HDAC and was made optional in July 2018 so that patients with sufficient disease response and performance status following Step 2 could proceed immediately to ASCT. Conditioning consisted of thiotepa 300 mg/m 2 ×2 days and busulfan 3.2mg/kg ×3 days (TT/Bu). Dose reductions of TT/Bu by 10% for every 5 years over the age of 60 were recommended as of May 2021. Progression-free survival (PFS) and overall survival (OS) were determined using the Kaplan-Meier method and compared between groups using the log-rank test. Results: The intention-to-transplant (ITT) cohort included 71 patients with median age 58 years (range 26-72), representing 81% of patients aged 18-60 and 55% of those aged 61-72 who were diagnosed with PCNSL in Alberta during the study period. The proportion of patients aged 61-72 who were treated with ITT increased from 42% before 2018 to 70% afterwards. Fifty-six (79%) ITT patients proceeded to ASCT while 15 (21%) did not due to poor performance status (n=6), treatment-related adverse events (n=5), or disease progression (n=4). There was 1 (1%) death due to infection-related non-relapse mortality (NRM) during induction. The routine omission of Step 3 starting in 2018 resulted in high transplantation rates at 29/35 (83%) compared to 27/36 (75%) in the preceding era. With median follow-up time 3.9 years, the 4-year PFS was 69% (95% CI 56-79%) and OS was 80% (95% CI 67-88%) in the ITT cohort (Figure 1A). For the 56 patients who received ASCT, 4-year PFS was 75% (95% CI 57-86%) and OS was 85% (95% CI 68-93%) from the time of ASCT. There was no significant difference in PFS between patients in complete response (CR)/unconfirmed CR versus partial response (PR) before ASCT (p=0.86); however, 5 patients with progressive disease before ASCT had inferior PFS compared to those with CR/CRu/PR (4-year PFS 40% vs 82%, p=0.0002). Relapse occurred in 8 (14%) patients at median 373 days (range 54-1411) after ASCT, including 7 with CNS relapse and 1 with systemic relapse. No patient in remission after ASCT received whole brain radiation therapy and most recovered without clinically significant neurologic deficits. There were no deaths due to transplant-related mortality. NRM occurred in 2 (4%) patients due to an unrelated cancer and stroke 1.1 and 4.3 years after ASCT, respectively. Among 27 patients &amp;gt;60 years old treated with ITT, 17 (63%) proceeded to ASCT, including 6 who received dose reductions of TT/Bu. The transplantation rate in this age group increased from 45% to 75% following the routine omission of Step 3. All 17 transplanted patients remain alive and in remission with median follow-up 2.5 years. Conclusion:In this real-world study of 71 patients with PCNSL, an abbreviated, low-intensity induction protocol resulted in high transplantation rates (~80%) and favorable long-term outcomes with 4-year OS 80%. Notably, TT/Bu conditioning achieved a low incidence of relapse with no transplant-related mortality observed, including among patients &amp;gt;60 years old. These data demonstrate that de-escalated induction therapy can result in improved rates of successful ASCT, thereby optimizing the outcomes of PCNSL.

Fluoroquinolone-Resistant Enterobacteriaceae Prevalence for Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation (aHSCT) in the Treatment of Multiple Myeloma (MM)

Background: Fluoroquinolones (FQL) are commonly used in antimicrobial prophylaxis in immunocompromised cancer patients (pts) during prolonged neutropenia. A possibly high and increasing proportion of pts harboring FQL-resistant Enterobacteriaceae (FRE) challenges the assumption that prophylaxis with FQLs is still of benefit in preventing sepsis. Previous studies reported that colonization of FRE in allogeneic transplant patients may be an infection risk factor (cf. Satlin et al. Clin Infect Dis 202;73:1257-65). This prospective study aims to determine the prevalence of FRE in defined pt populations in two metropolitan areas treated with dose-intense melphalan with autologous peripheral blood stem cell (PBSC) transplantation, and to determine the possible clinical effects of FRE in the host microbiome on transplant outcomes. Methods: Pts eligible for this prospective, ongoing study have a diagnosis of MM and are undergoing autologous PBSC transplantation after conditioning with dose-intense melphalan 200 mg/m 2 at Hackensack University Medical Center (HUMC) and MedStar Georgetown University Hospital (MGUH). Peri-rectal swabs are scheduled before chemotherapy mobilization of PBSC given with FQL prophylaxis, before transplant admission with initiation of antimicrobial prophylaxis, at time of hospital discharge, and 3 months after aHSCT. Prophylaxis is discontinued with fever or hospital discharge. Blood cultures are obtained at time of fever (&amp;gt;38 °C) with adjustments in antibiotics per standard of care. A central catheter is placed for venous access in all patients throughout their transplant course. Pts are discharged after achieving neutrophil (ANC) engraftment and control of conditioning regimen toxicities. Bacterial cultures from perirectal swabs (fresh or frozen for shipping) were purified on CHROMagar™ Orientation Plates and grown in the presence of ≥5 ug/ml ciprofloxacin to select for quinolone-resistant organisms. Results: To date, 39 pts are evaluable (Table 1). PBSC were mobilized using filgrastim/plerixafor (G-Moz) or cyclophosphamide/etoposide/dexamethasone (CDE) followed by filgrastim with levofloxacin prophylaxis. The quantity of CD34+ cells infused is in Table 1. All pts achieved ANC engraftment at a median of 10.8 days (range 9-14) and were hospitalized for a median of 13 days (range 11-24). 37/39 pts collected swabs before transplant admission (and swabs were obtained at discharge for the other 2 pts). 13/37 (35%) admission swabs demonstrated FRE colonization (Table 2). 6/33 swabs at time of discharge were positive for FRE including for 4 pts negative for FRE on transplant admission with a total of 17/39 pts (44%) showing FRE colonization at some point during the transplant admission. Samples collected at 3 months after transplantation for 24 pts reaching that timepoint showed FRE colonization for 4 pts including 2 pts not previously testing positive at time of transplantation. 27/107 samples tested positive for FRE and 21/39 pts (54%) had at least one FRE positive culture. Seven pts (20%) developed neutropenic fever but no pt experienced a blood-stream infection (BSI). One pt developed Clostridium difficile colitis during the period of neutropenia. One pt tested positive for MRSA colonization at admission but did not develop fever or BSI. One pt was readmitted after initial hospital discharge for evaluation of fever without a source of infection determined. Ten pts (5 FRE colonized during transplant course) were given prednisone for persistent diarrhea attributed to engraftment syndrome (cf: Spitzer TR. Bone Marrow Transplant 2001;27:893-8) commencing at a median of 10 (range, 8-13) days after aHSCT and not associated with CDE mobilization or detection of FRE. Nineteen other patients, 8 of whom tested positive for FRE, did not receive corticosteroids for management of regimen-related toxicities (an additional 7 pts received preplanned corticosteroids starting at day +8). No center effect is yet evident. Conclusions: FRE are detected in a high proportion of pts undergoing aHSCT in the treatment of MM. However, FQL prophylaxis is not associated with FRE BSI in this ongoing study. FRE colonization is not predictive of delayed engraftment or prolonged hospitalization, and does not appear predictive of non-infectious diarrhea.

Differential roles of prostaglandin E2 EP4 receptor on stromal cell populations for hematopoietic stem and progenitor cell function

Prostaglandin E2 (PGE2) signaling through its EP4 receptor regulates hematopoietic stem and progenitor cell (HSPC) functions. Here we generated mouse strains with conditional and inducible deletion of EP4 in stromal cell populations, including osteolineage cells, mesenchymal progenitor cells, perivascular stromal cells, and endothelial cells, to evaluate the role of EP4 in HSPC regulation through signaling in each of these niche cell populations. We found that EP4 deletion in different stromal cells had distinct effects on HSPC proliferation, long-term repopulating capacity, and the peripheral blood stem cell mobilization response. Lack of EP4 signaling in osteolineage cells increased HSPC number but impaired their long-term engraftment and mobilization. EP4 deletion in mesenchymal progenitor cells and endothelial cells reduced HSPC number and function, while EP4 deletion in perivascular stromal cells had sex-specific effects on HSPC engraftment. Our results demonstrate that PGE2/EP4 signaling in bone marrow stromal cells plays a significant and complex role in HSPC regulation, with both positive and negative effects depending on the stromal cell type.

Stem cell collection after lenalidomide, bortezomib and dexamethasone plus elotuzumab or isatuximab in newly diagnosed multiple myeloma patients: a single centre experience from the GMMG-HD6 and -HD7 trials

BackgroundWhile quadruplet induction therapies deepen responses in newly diagnosed multiple myeloma patients, their impact on peripheral blood stem cell (PBSC) collection remains incompletely understood. This analysis aims to evaluate the effects of prolonged lenalidomide induction and isatuximab- or elotuzumab-containing quadruplet induction therapies on PBSC mobilization and collection.MethodsA total of 179 transplant-eligible patients with newly diagnosed MM treated at a single academic center were included. The patients were evaluated based on PBSC mobilization and collection parameters, including overall collection results, CD34+ cell levels in peripheral blood, leukapheresis (LP) delays, overall number of LP sessions, and the rate of rescue mobilization with plerixafor. The patients underwent four different induction regimens: Lenalidomide, bortezomib, and dexamethasone (RVd, six 21-day cycles, n = 44), isatuximab-RVd (six 21-day cycles, n = 35), RVd (four 21-day cycles, n = 51), or elotuzumab-RVd (four 21-day cycles, n = 49).ResultsThe patients' characteristics were well balanced across the different groups. Collection failures, defined as the inability to collect three sufficient PBSC transplants, were rare (n = 3, 2%), with no occurrences in the isatuximab-RVd and elotuzumab-RVd groups. Intensified induction with six 21-day cycles of RVd did not negatively impact the overall number of collected PBSCs (9.7 × 106/kg bw versus 10.5 × 106/kg bw, p = 0.331) compared to four 21-day cycles of RVd. Plerixafor usage was more common after six cycles of RVd compared to four cycles (16% versus 8%). Addition of elotuzumab to RVd did not adversely affect overall PBSC collection (10.9 × 106/kg bw versus 10.5 × 106/kg bw, p = 0.915). Patients treated with isatuximab-RVd (six cycles) had lower numbers of collected stem cells compared to those receiving RVd (six cycles) induction (8.8 × 106/kg bw versus 9.7 × 106/kg bw, p = 0.801), without experiencing significant delays in LP or increased numbers of LP sessions in a multivariable logistic regression analysis. Plerixafor usage was more common after isatuximab plus RVd compared to RVd alone (34% versus 16%).ConclusionsThis study demonstrates that stem cell collection is feasible after prolonged induction with isatuximab-RVd without collection failures and might be further explored as induction therapy.Trial registrationPatients were treated within the randomized phase III clinical trials GMMG-HD6 (NCT02495922, 24/06/2015) and GMMG-HD7 (NCT03617731, 24/07/2018). However, during stem cell mobilization and -collection, no study-specific therapeutic intervention was performed.

A phase II study of gemcitabine, carboplatin, dexamethasone, and rituximab in patients with relapsed or refractory non-Hodgkin lymphoma.

This study evaluated the efficacy and safety of salvage chemotherapy with gemcitabine, carboplatin, dexamethasone, and rituximab (GCD±R) for Japanese patients with relapsed or refractory non-Hodgkin lymphoma (NHL). A multicenter, phase II trial of GCD±R administered every 3weeks for up to 6 cycles was conducted. Rituximab was administered as a therapeutic strategy for CD20-positive lymphoma. The primary endpoint was the complete response (CR) rate. Secondary endpoints included the overall response (OR) rate, overall survival (OS), progression-free survival (PFS), toxicity, and success rate of peripheral blood stem cell collection for eligible transplant patients. A total of 25 patients (median age 66years) were evaluated, with a median follow-up period of 66.7months. CR and OR rates were 28% and 52%, respectively. Median PFS and OS were 8.7 and 32.2months, respectively. The major toxicity was myelosuppression, but the regimen was generally well-tolerated, with a low incidence of febrile neutropenia (20%) and no treatment-related deaths. Of the 6 patients who were eligible for autologous stem cell transplantation and underwent peripheral blood stem cell mobilization, the required number of CD34-positive cells was collected in 5 (83%). All 6 proceeded to transplantation and achieved successful engraftment without recurrence. The present results suggest that GCD±R may be effective and well-tolerated in Japanese patients with relapsed or refractory NHL. However, further investigation is needed to confirm these results.

Comparison of Plerixafor or Cyclophosphamide Combined with G-CSF in Mobilization of Peripheral Blood Stem Cells in Multiple Myeloma

To compare the efficacy of plerixafor (PXF) combined with granulocyte colony-stimulating factor (G-CSF) (PXF+G-CSF) and cyclophosphamide (Cy) combined with G-CSF (Cy+G-CSF) in the mobilization of peripheral blood stem cells (PBSCs) in patients with multiple myeloma (MM). The clinical data of 41 MM patients who underwent PBSC mobilization using PXF+G-CSF (18 cases) or Cy+G-CSF (23 cases) in Shanxi Bethune Hospital from January 2019 to December 2021 were retrospectively analyzed, including the count of collected CD34+ cells, acquisition success rate, failure rate, and optimal rate. The correlation of sex, age, disease type, DS staging, ISS staging, number of chemotherapy cycle, disease status before mobilization, and mobilization regimen with the collection results was analyzed, and the adverse reactions, length of hospital stay, and hospitalization costs were compared between the two mobilization regimens. The 41 patients underwent 97 mobilization collections, and the median number of CD34+ cells collected was 6.09 (0-34.07)×106/kg. The acquisition success rate, optimal rate, and failure rate was 90.2%, 56.1%, and 9.8%, respectively. Univariate analysis showed that sex, age, disease type, and disease stage had no significant correlation with the number of CD34+ cells collected and acquisition success rate (P >0.05), but the patients with better disease remission than partial remission before mobilization were more likely to obtain higher CD34+ cell count (P <0.05). The PXF+G-CSF group had a larger number of CD34+ cells and higher acquisition success rate in the first collection than Cy+G-CSF group (both P <0.05), and had lower infection risk and shorter length of hospital stay during mobilization (both P <0.05), but the economic burden increased (P <0.05). PXF+G-CSF used for PBSC mobilization in MM patients has high first acquisition success rate, large number of CD34+ cells, less number of collection times, and short length of hospital stay, but the economic cost is heavy.

Efficacy and Safety of Etoposide Combined with Cyclophosphamide for Autologous Peripheral Blood Stem Cell Mobilization in Patients with Multiple Myeloma

To evaluate the efficacy and safety of etoposide combined with cyclophosphamide (EC) regimen for mobilization of autologous peripheral blood stem cells (APBSCs) in patients with multiple myeloma (MM). The clinical data of 48 MM patients who received APBSC transplantation (APBSCT) in Department of Hematology of the First Affiliated Hospital of Nanchang University from January 2015 to October 2021 were retrospectively analyzed. The mobilization success rate and mobilization optimal rate of EC regimen were counted, and its effect on transplant efficacy, adverse reactions, hematopoietic reconstitution after transplantation, and survival time of MM patients were analyzed. APBSCs were collected on day 14 (10-19) after EC administration. The median of collected CD34+ cells was 6.82 (1.27-22.57)×106/kg, and the median number of apheresis session was 2 (1-4). The mobilization success rate (collecting CD34+ cells≥2×106 cells/kg after completion of apheresis) was 98% (47/48), and mobilization optimal rate (collecting CD34+ cells≥5×106 cells/kg after completion of apheresis) was 71% (34/48). The depth of remission were improved after APBSCT, and the complete remission (CR) rate increased from 45.8% before transplantation to 87.5% after transplantation (P <0.01). There was no transplant-related death, no blood transfusion during mobilization, and no mucositis occurred in the patients. The most common complication was neutropenia, with an incidence of 75.0% (36/48). After transplantation, all the patients successfully achieved hematopoietic reconstitution. The median time to neutrophil engraftment was 10 (9-26) days, and median time to platelet engraftment was 10 (8-33) days. By the end of follow-up, both the median progression-free survival (PFS) and overall survival (OS) time were not reached. The 5-year estimated PFS rate and OS rate was 53.8% and 82.4%, respectively. The EC regimen for mobilization of APBSC has a high acquisition success rate and controllable adverse reactions, which can be an effective and safe mobilization regimen in MM patients.

Prospective Comparative Study of Etoposide plus G-CSF versus G-CSF Alone, Followed by Risk-Adapted Plerixafor for Peripheral Blood Stem Cell Mobilization in Patients with Newly Diagnosed Multiple Myeloma: CAtholic REsearch Network for Multiple Myeloma Study (CAREMM-2001).

To explore the optimal mobilization for multiple myeloma (MM) patients, we conducted a prospective trial comparing single-dose etoposide (375 mg/m2 for one day) plus G-CSF versus G-CSF alone, followed by risk-adapted plerixafor. After randomization, 27 patients in the etoposide group and 29 patients in the G-CSF alone group received mobilizations. Six (22.2%) patients in the etoposide group and 15 (51.7%) patients in the G-CSF alone group received plerixafor based on a peripheral blood CD34+ cell count of < 15/mm3 (p = 0.045). The median count of CD34+ cells collected was significantly higher in the etoposide group (9.5 × 106/kg vs. 7.9 × 106/kg; p = 0.018), but the optimal collection rate (CD34+ cells ≥ 6 × 106/kg) was not significantly different between the two groups (96.3% vs. 82.8%; p = 0.195). The rate of CD34+ cells collected of ≥ 8.0 × 106/kg was significantly higher in the etoposide group (77.8% vs. 44.8%; p = 0.025). Although the rates of grade II-IV thrombocytopenia (63.0% vs. 31.0%; p = 0.031) and grade I-IV nausea (14.8% vs. 0%; p = 0.048) were significantly higher in the etoposide group, the rates of adverse events were low in both groups, with no neutropenic fever or septic shock. Thus, both single-dose etoposide plus G-CSF and G-CSF alone with risk-adapted plerixafor were effective and safe, but the former may be the better option for patients who are expected to receive two or more transplantations.

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.

The Effect of Iron Overload on the Mobilization of Peripheral Blood Hematopoietic Stem Cells in Pediatric Patients with Thalassemia Major

Introduction: The purpose of this study was to examine the effect of iron overload on the mobilization of peripheral blood stem cells (PBSCs) in pediatric patients with β-thalassemia major (TM). Methods: We retrospectively reviewed the records of 226 patients with TM from whom PBSCs were collected. Iron overload was based on serum ferritin level, and liver and cardiac iron overload was measured by magnetic resonance imaging (MRI) T2*. Results: The mean age of the TM patients was 7.35 ± 3.41 years. Of the patients, only 171 received MRI. Of the 171 patients, 35 had normal liver iron levels, 39 mild liver iron overload, 90 intermediate liver iron overload, and 7 severe liver iron overload. The intermediate + severe group was associated with significantly higher age and BMI and lower leukapheresis product white blood cell count and CD34⁺ cell levels (all, p < 0.05). Conclusion: Leukapheresis indices were similar between patients with different degrees of iron overload according to the ferritin level and cardiac iron overload, in which the later might be due to the small number of patients with cardiac overload. In patients with TM, the intermediate and severe liver iron overload was associated with poorer mobilization of PBSCs.