Collection Of CD34 Research Articles

Anti-CD38 monoclonal antibody impairs CD34+ mobilization and affects clonogenic potential in multiple myeloma patients.

Induction with daratumumab-based regimens followed by autologous stem cell transplantation is the current standard for newly diagnosed multiple myeloma (NDMM) patients eligible for intensive chemotherapy. However, concerns emerged regarding potential negative effects following daratumumab-based treatment on CD34+ mobilization. We here compared CD34+ mobilization and clonogenic potential between daratumumab and non-daratumumab based therapy without upfront plerixafor administration among patients affected by NDMM. Clinical, mobilization and clonogenic data from 41 consecutively enrolled NDMM patients were analyzed. Patients underwent collection of autologous CD34+ by apheresis at the ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy, from January 2021 to March 2023. Clonogenicity analysis was performed on BFU-E and CFU-GM. Seventy-five percent of daratumumab-treated patients underwent >1 apheresis, compared to 24% of non-daratumumab patients (p=0.0017). Daratumumab-treated patients had significantly lower CD34+ count (mean 38 vs 79/μL, respectively; p=0.0011), with a median CD34+ harvest of 3.98×106/kg (range 1.68-9.18) vs 6.87×106/kg (range 1.63-16.85) in non-daratumumab-treated (p=0.0006). In multivariate analysis the likelihood of undergoing >1 apheresis was significantly higher in older patients (OR 1.2, 95% CI 1-1.4, Z=2.10, p=0.03) and daratumumab-treated patients (OR 15, 95% CI 2.8-129, p=0.004). Moreover, daratumumab-based induction therapy demonstrated an independent negative association with BFU-E colony formation (p=0.0148), even when accounting for patient age and CD34+ levels. Our findings underscore the impact of daratumumab-based treatment on CD34+ mobilization in a real-life, upfront plerixafor-free population of NDMM patients. Higher probability of requiring multiple apheresis occurred among daratumumab-treated patients. Interestingly, the observation that daratumumab might negatively impact BFU-E colony formation, independent of CD34+ cell count, offers novel biological perspectives. Appropriate strategies should be adopted by the Apheresis teams to mitigate these potential negative effects.

ОЦЕНКА БЕЗОПАСНОСТИ И ЭФФЕКТИВНОСТИ МЕТОДИКИ МОБИЛИЗАЦИИ И СБОРА ГЕМОПОЭТИЧЕСКИХ СТВОЛОВЫХ КЛЕТОК У ДЕТЕЙ РАЗНЫХ ВОЗРАСТНЫХ ГРУПП СО ЗЛОКАЧЕСТВЕННЫМИ НОВООБРАЗОВАНИЯМИ: ОПЫТ ОДНОГО ЦЕНТРА

High dose chemotherapy (HDCT) with autologous hematopoietic stem cell transplantation (auto-HSCT) is used currently as a consolidating stage in cancer treatment protocols for children from different age groups with various malignant neoplasms. Auto-HSCT can improve both progression-free survival and overall survival of such patients. At the same time the optimization of the collection of autologous hematopoietic stem cells (HSCs) seems to be an important factor in the successful implementation of auto-HSCT. The purpose of this research was to evaluate the safety and effectiveness of the HSCs mobilization and collection method in children from different age groups with various malignancies. Materials and methods used: a single-center retrospective cohort study of 258 pediatric patients (median body weight 20.0 [13.8; 42.0] (7.0-95.0) kg and median height 116 [97; 155] (55.0-189) cm) with various cancers aged 1 to 18 y/o (median 78.0 [36; 144] (3-215) months old) who received treatment in Jan. 2020-Jan. 2023 at the Research Institute of Pediatric Oncology and Hematology named after Academician L.A. Durnov with the N.N. Blokhin Russian Cancer Research Center (Moscow, Russia). Patients were divided into 3 age groups: younger than 1 y/o, 1 to 10 y/o and 11 to 18 y/o. Results: 242 (93.8%) of HSC apheresis procedures were successful on the first attempt, 16 patients underwent repeated apheresis (a total of 274 procedures were performed). The median number of CD34+ cells obtained was 110.95 [45.6; 276.4] (0.70-2338.2) cells/µl, median apheresis duration was 253.5 [189; 338] (82-575) min. No serious complications were observed during the HSCs mobilization and collection in any patient. None of the patients developed hemodynamic disturbances. The main criteria for effectiveness was the CD34+/kg level, the median of which was 5.1 [2.4; 12.7] (0.01-95.6)•106. One of the safety criteria for the patients from all the three age groups was the absence of hemodynamic disorders and citrate reactions in the form of numbness, cyanosis of the skin and respiratory disorders. Another important safety criteria were the absence of a significant decrease in both platelet and hemoglobin levels. The median platelet levels prior to the procedure was 125.5 [68; 210] (14.0-815)•109/l and 129 [73; 210] (17.0-823)•109/l at the end of the procedure (p<0.001). Hemoglobin levels before and after the procedure were 100 [94; 110] (75-242) g/l and 99 [93; 109] (70-142) g/l, respectively (p<0.001). Considering it safe to reduce hemoglobin (g/l) and/or platelets (•109/l) by no more than 10 units in each measurement, in 87.6±4.1% (83.0-91.1) of observed cases the procedure was safe without statistically significant differences in all age groups. The effectiveness of the HSCs mobilization and collection method proposed by the Authors in children of the older age group (11 to 18 y/o) was the lowest and was statistically significantly different from the effectiveness in the group of children aged 1 to 10 y/o (p<0.001) with cancer and amounted to 84.5±4.4% (79.6-88.4). Conclusion: with the multidisciplinary team of practitioners, HSC apheresis in children is a safe and effective technique used as part of the complex cancer treatment in patients from poor prognosis groups. The apheresis algorithm that the Authors have proposed allows high-quality collection of CD34+ positive cells in amounts sufficient for further auto-HSCT.

Novel Clinically Useful Inhibitor of Mediator Complex, RVU120, Relives Differentiation Block in MDS/AML

Background: Myelodysplastic Syndrome (MDS) and Acute Myeloid Leukemias (AML) are characterized by a block in hematopoietic differentiation that can often be traced to aberrant stage-specific transcription. The kinase module of the mediator complex, consisting of CDK8, its paralog CDK19, Cyclin C, MED12, and MED13, have been identified as a molecular switch that regulates gene expression. A variety of cancers have exploited this mechanism to maintain stemness and an undifferentiated state. RVU120 is a first-in-class, specific, and selective inhibitor of CDK8/19, currently in Phase Ib clinical trial in patients with AML or High-Risk MDS (HR-MDS) (NCT04021368). RVU120 has been shown to stimulate erythroid differentiation in transformed CD34+ cord blood (CB) cells and in CD34+ cells from Diamond-Blackfan Anemia (DBA). To evaluate the further therapeutic potential of CDK8/19 inhibition, we confirmed aberrant expression of mediator complex components and erythroid-stimulating activity in a collection of CD34+ primary samples of AML and MDS. Results: We investigated the expression of mediator complex components in a large database of MDS CD34+ marrow samples and age-matched controls. Our findings revealed that MED12, a critical component of the mediator complex, was significantly overexpressed in MDS samples from refractory anemia with excess blasts (RAEB), a higher risk subset of MDS(p=0.018) (Fig A). Furthermore, we observed that this overexpression of MED12 was associated with a higher rate of transformation to AML. To delve deeper, we examined the expression of MED12 in sorted leukemic stem cells from primary AML samples and found significantly elevated levels in Long Term Hematopoietic Stem Cells from AML samples with both normal karyotype and complex karyotypes compared to healthy controls. Next, we conducted an evaluation of the efficacy of the mediator kinase module inhibition in MDS-derived cell line (MDS-L). Inhibition of CDK8/19 with RVU120 led to increased erythroid differentiation in this model which confirmed our observations in transformed CD34+ CB cells in CB cells, these phenotypic changes were correlated with the inhibition of CDK8-dependent phosphorylation marker S726 on STAT5 and a profound increase in the expression of genes involved in erythroid commitment and hemoglobin metabolism. In order to confirm therapeutic potential of CDK8/CDK19 inhibition in MDS and AML, we performed colony-forming assay on primary samples of MDS and AML (n= 15). The treatment with RVU120 resulted in increased erythroid differentiation in a majority of samples, evident from an augmented number of colonies. Detailed analysis indicated changes in the expression of erythroid differentiation markers, including increased CD71 and Glycophorin A expression on colonies, as assessed by FACS analysis (Figure B, shows representative sample). Conclusion Our data highlight that inhibition of the overexpressed mediator complex proteins can alleviate the differentiation blocks seen in MDS/AML. These results provide a compelling rationale for further developing the CDK8/19 inhibitor RVU120 for transfusion- dependent MDS/AML patients.

Resource Utilization Analysis of Two Algorithms for Hematopoietic Progenitor Cell Mobilization in Multiple Myeloma

Background: Autologous hematopoietic cell transplantation (HCT) is a standard of care after induction therapy for multiple myeloma (MM). A key step in this procedure is the mobilization and collection of hematopoietic progenitor cells (HPC). HPC mobilization typically uses G-CSF with or without the CXCR4 antagonist Plerixafor (P). Although P increases the effectiveness of mobilization and may reduce the number of apheresis sessions, it is associated with significantly increased cost per dose. There is significant heterogeneity to HPC collection algorithms across institutions and there is no clear standard. At the Cleveland Clinic, our HPC collection algorithm was updated in an effort to reduce the use and associated cost of P. The criteria for initiating P became more stringent and far fewer patients were initiated on P prior to their first session of HPC collection apheresis. Prior to October 2017, patients were initiated on P if any 1 of the following criteria were met: age>60 years, prior treatment with melphalan or other alkylating therapy, prior treatment with lenalidomide >2 cycles, extensive bone marrow disease, or platelet count <100K. Starting October 1, 2017, patients were preemptively initiated on P prior to first collection only if all 3 of the following criteria were met: age > 65 years, lenalidomide > 6 cycles, and platelet count < 100K. However, P was added after the first apheresis session if peripheral blood CD34+ cell count was <20/uL or HPC yield was unsatisfactory (<2 x 10^6 CD34+ cells). Furthermore, target CD34 yield was decreased from 5 to 4 x 10^6 CD34+ cells. Herein, we perform a comparative resource utilization analysis of HPC collection at our center. Methods: We retrospectively collected HPC mobilization data on patients undergoing HCT for MM from 1/12014 to 12/31/2020. We determined the number of P doses, number of apheresis sessions, and HPC collection totals per patient. Patient characteristics were summarized in median, interquartile range (IQR), or frequencies and percentages as appropriate. Fisher's exact test and Wilcoxon rank sum test were used to compare variables in patients undergoing mobilization prior to versus after 10/1/2017. All tests were two-sided and p-values of 0.05 or less were considered statistically significant. Results: 219 patients underwent HPC mobilization from 1/1/2014 to 9/30/2017 and 251 patients underwent mobilization after algorithm change from 10/1/2017 to 12/31/2020. As anticipated, the protocol change decreased the number of patients receiving P prior to their first apheresis session. 91% received P prior to the first apheresis session before the change while 14% received this initial dose of P after the change. Prior to the change 51% of patients completed collection in 1 day, 30% completed in 2 days, 12 % completed in 3 days, and 7% completed in 4 days or more. These figures changed to 20%, 41%, 23%, and 17% respectively following the change (p<0.0001) Median day 1 peripheral blood CD34 count decreased from 63 to 19 cells/uL while median day 1 CD34 collection yield fell from 4.8 to 1.46 x 10^6 after the change (p<0.0001) (Table 1). Total CD34 collection yield also decreased from a median of 6.64 to 4.6 x 10^6 CD34+ cells (p<0.0001). However, the target yield was decreased from 5 to 4 x 10^6 CD34+ cells as described above. The number of doses of P per patient decreased after the change (pre-change median dose / patient = 1, IQR = 1-2) (post-change median dose / patient = 1, IQR = 0-2) (p=0.004). The average number of apheresis sessions required per patient increased following the change (pre-change median apheresis sessions = 1, IQR = 1-2) (median post change apheresis sessions = 2, IQR = 2-3) (p<0.0001) (Figure 1). Conclusion: Changes to our institutional HPC mobilization algorithm led to a substantial decrease in the use of preemptive P prior to day 1 of collection by design. The resulting decrease in total doses of P per patient was smaller than expected, although still statistically significant. However, this was offset by a concomitant significant increase in the number of apheresis sessions required per patient despite a lower collection target. Based on these results, a cost analysis is ongoing in order to re-evaluate our institutional algorithm.

Autologous Hematopoietic Stem Cell Transplantation Combined with High-Dose Chemotherapy As First-Line Treatment for HIV-Associated Lymphoma: A Retrospective Analysis

BACKRGOUND At present, lymphoma is one of the three most common malignant tumors in AIDS patients. With the popularization of cART treatment, the incidence of AIDS-associated lymphoma has decreased, but it is still higher than that in the general population with poor prognosis. The Central and Western China AIDS Lymphoma League (CALL) is committed to investigate the efficacy and related factors of autologous hematopoietic stem cell transplantation (auto-HSCT) as consolidation therapy for newly diagnosed HIV-associated lymphoma. METHODS From 2018 to 2023, 11 newly diagnosed patients with AIDS-associated lymphoma in our center were collected, including 10 males and 1 female, 2 of whom received double ASCT, with a median age of 38 years (range 25-64 years). One case (11.1%) had bone marrow involvement, 3 cases (27.3%) had low/low-intermediate risk according to IPI, and 2 cases (63.6%) had high/intermediate risk according to IPI. Ten patients (90.9%) achieved complete remission (CR) and 1 patient (9.1%) achieved partial remission (PR) before transplantation. RESULTS Among the 11 patients, 2 patients (1 with high-risk diffuse large B cell lymphoma and 1 with plasmablastic lymphoma) received double transplantation within 6 months, and the remaining patients received single transplantation. The median CD34 collection before transplantation was 4.67 (2.5-12.52) *10^6/kg. 3 patients received BeEAC regimen, 7 patients received BeEAM regimen, and 1 patient received IAC regimen for the second transplantation. Five patients (45%) developed various degrees of infection during transplantation, which was improved after anti-infection treatment. All patients achieved hematopoietic reconstitution. The median time of neutrophil and platelet engraftment was 11.9 ± 2.23 days and 12.1 ± 2.96 days, respectively. At a median follow-up of 12 (3-14) months after transplantation, 1 patient died within 100 days after transplantation, 1 patient died of Covid-19 virus infection, 1patient achieved PR, other 8 patients remained CR.. Patient no. 1 died from bacteremia 1 months after ASCT. Patient no. 8 relapsed 6 months after ASCT and died from Covid-19 virus infection when 5 months after ASCT. Patient no. 9 relapsed 6 months after ASCT, but is still alive in second CR and is receiving lenalidomide maintenance therapy. Other 8 patients in CR post-ASCT are receiving lenalidomide/Interferon/rituximab maintenance therapies. Therefore, overall survival for the 11 transplanted patients is 81% at 12 months, with a median follow-up of 12 months (range 5-60 months). Furthermore, eight patients remained in CR, for an progression-free survival of 72% at 12 months, with a median follow-up of 19 months (range 9-60 months).It is worth mentioning that active HIV replication was not monitored with the continuous use of cART agents during lymphoma chemotherapy and ASCT; cART administration did not affect the number of harvested stem cells or the time to engraftment after transplantation.

Predicting the CD34 content of mobilized peripheral blood leukapheresis products: single institution experience over 20 years

Background aimsSince the standardization of CD34 measurement by flow cytometry, predictors of leukapheresis CD34 yield have played a pivotal role in planning donor leukaphereses. We describe here a single institution's experience with a multivariate predictor that was used for 2,929 products without alteration for 20 years. MethodsThe ordinary least squares regression model variables included log peripheral CD34 count, collection duration (3- versus 4-hours), collection number, donor sex, and transplant type. ResultsDuring the study period we changed flow cytometers twice and leukapheresis instruments once. During the Cobe Spectra era the predictor explained 90% of the variability in CD34 collection yield for autologous transplants (r2 = 0.90), and 70% for allogeneic transplants with an overall sensitivity to predict a CD34 yield of ≥ 1 × 106/kg of 97.7%, and specificity of 81.4%. ConclusionsImplemented prospectively with real-time result reporting, the model allowed us to predict CD34 yield with both 3- and 4-hour collection scenarios. Given this guidance, 3-hour collections were selected by the clinical team 25% of the time, saving patient leukapheresis time and resources. When faced with a prediction of < 1 × 106 CD34/kg, the clinical team chose to defer collection 72% of the time. In instances where leukapheresis was performed despite a poor predicted outcome, 85% of patients collected on the Cobe Spectra, and 92% of patients collected on the Optia, failed to collect at least 1 × 106 CD34/kg. A revised model is tested retrospectively on Optia data, and suggestions for further improvements are discussed.

GPC-100, a novel CXCR4 antagonist, improves in vivo hematopoietic cell mobilization when combined with propranolol.

Autologous Stem Cell Transplant (ASCT) is increasingly used to treat hematological malignancies. A key requisite for ASCT is mobilization of hematopoietic stem cells into peripheral blood, where they are collected by apheresis and stored for later transplantation. However, success is often hindered by poor mobilization due to factors including prior treatments. The combination of G-CSF and GPC-100, a small molecule antagonist of CXCR4, showed potential in a multiple myeloma clinical trial for sufficient and rapid collection of CD34+ stem cells, compared to the historical results from the standards of care, G-CSF alone or G-CSF with plerixafor, also a CXCR4 antagonist. In the present study, we show that GPC-100 has high affinity towards the chemokine receptor CXCR4, and it potently inhibits β-arrestin recruitment, calcium flux and cell migration mediated by its ligand CXCL12. Proximity Ligation Assay revealed that in native cell systems with endogenous receptor expression, CXCR4 co-localizes with the beta-2 adrenergic receptor (β2AR). Co-treatment with CXCL12 and the β2AR agonist epinephrine synergistically increases β-arrestin recruitment to CXCR4 and calcium flux. This increase is blocked by the co-treatment with GPC-100 and propranolol, a non-selective beta-adrenergic blocker, indicating a functional synergy. In mice, GPC-100 mobilized more white blood cells into peripheral blood compared to plerixafor. GPC-100 induced mobilization was further amplified by propranolol pretreatment and was comparable to mobilization by G-CSF. Addition of propranolol to the G-CSF and GPC-100 combination resulted in greater stem cell mobilization than the G-CSF and plerixafor combination. Together, our studies suggest that the combination of GPC-100 and propranolol is a novel strategy for stem cell mobilization and support the current clinical trial in multiple myeloma registered as NCT05561751 at www.clinicaltrials.gov.

Evaluating the efficiency and safety of large-volume leukapheresis using the Spectra Optia continuous mononuclear cell collection protocol for peripheral blood stem cell collection from healthy donors: A retrospective study.

Large-volume leukapheresis (LVL) refers to processing of more than three volumes of blood in a single session for peripheral blood stem cell collection. Recently, continuous mononuclear cell collection (cMNC) protocol has been developed using the Spectra Optia system, which is a widely used apheresis device. LVL using the novel protocol has been investigated in patients. However, the efficiency and safety of LVL in healthy donors using this protocol has not been characterized. Therefore, this study aimed to evaluate the efficiency and tolerability of CD34+ collection of LVL with the cMNC protocol in healthy donors. We retrospectively collected data on LVL (>3 total blood volume) and normal-volume leukapheresis (NVL) performed in healthy donors between October 2019 and December 2021. All procedures were performed using the cMNC protocol. Although pre-apheresis CD34+ cell count was lesser in LVL (23.5 vs. 58.0/μL, p < .001), CD34+ collection efficiency was comparable between LVL and NVL (61.2% vs. 61.4%, p = .966). Platelet loss was significantly higher in LVL compared to NVL (38.0% vs. 29.4%, p < .001), with no correlation between attrition of platelet and processing blood volume. Moreover, the incidence of citrate toxicity during procedures was comparable between the two groups (31.6% vs. 21.4%, p = .322). All LVL procedures could be completed without any adverse events. Allogeneic LVL procedure using Spectra Optia cMNC protocol was well tolerated by the donors and resulted in efficient collection of CD34+ cells, which was comparable to that of NVL.

Feasibility of peripheral blood stem cell collection from sickle cell trait donors with an intensified G-CSF regimen.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment for SCD and bone marrow from an HLA-matched sibling is currently the standard of care. Haploidentical HSCT from a family donor with a TCR αβ/CD19 depleted graft (T-haplo) is an increasingly successful alternative, which requires the generation of G-CSF stimulated peripheral stem cell (PBSC) from haploidentical relatives. These sickle cell trait (SCT) donors reported to develop SCD-related complications in conditions of severe stress. In this retrospective analysis, we compared the safety and efficacy of PBSC mobilization with a G-CSF intensified mobilization regimen in SCT donors with a conventional G-CSF mobilization regimen in healthy donors. The reported adverse events were similar during intensified G-CSF mobilization, apheresis, and shortly after stem cell apheresis in SCT and control donors. In SCT and control donors, we were able to mobilize high yields of CD34+ stem cells and the harvested CD34+ cell count was comparable with control donors. Peripheral stem cell mobilization using an intensified G-CSF regimen is safe, and well tolerated among SCT donors. SCT donors are a valid alternative for collection of peripheral CD34+ stem cells for T-cell-depleted haploidentical stem cell transplantation.

Comparison of Biosimilar Filgrastim with Innovator Fligrastim for Peripheral Blood Stem Cells Mobilization, Collection of CD34+ Stem Cells, and Engraftment in Patients Undergoing Autologous and Allogeneic Stem Cell Transplantation: A Single-Center Experience.

BACKGROUND In the Middle East, there is lack of data on peripheral blood CD34+stem cells mobilization by using biosimilar filgrastim. We have been using both Neupogen and a biosimilar G-CSF) Zarzio® (as a mobilizing agent since February 2014 for both allogenic and autologous stem cell transplantations. MATERIAL AND METHODS This was a single-center retrospective study. All patients and healthy donors who received either the biosimilar G-CSF (Zarzio®) or original G-CSF (Neupogen®) for mobilization of CD34+ stem cells were included in the study. The primary goal was to determine and compare the rate of successful harvest and amount of CD34+ stem cells collected in either adult cancer patients or healthy donors between Zarzio® and Neupogen® groups. RESULTS A total of 114 patients, including 97 cancer patients and 17 healthy donors, underwent successful CD34+ stem cell mobilization using G-CSF with chemotherapy (35 with Zarzio® +chemotherapy, 39 with Neupogen® +chemotherapy) or G-CSF as monotherapy (14 with Zarzio®, 9 with Neupogen®) in autologous transplantation. In an allogeneic stem cell transplantation, successful harvest was achieved by using G-CSF monotherapy (8 with Zarzio®, 9 with Neupogen®). There was no difference between Zarzio® and Neupogen® in the amount of CD34+ stem cells collected at leukapheresis. There was no difference with regards to secondary outcomes between the 2 groups. CONCLUSIONS Our study showed that biosimilar G-CSF (Zarzio®) has comparable efficacy to the original G-CSF (Neupogen®) when used for mobilization in both autologous and allogenic stem cell transplantation and was associated with significant cost saving.

Biochemical Engraftment and Clinical Outcomes Following Ex-Vivo Autologous Stem Cell Gene Therapy for Mucopolysaccharidosis Type IIIA

Background: Mucopolysaccharidosis type IIIA (MPSIIIA, Sanfilippo syndrome) is a lysosomal storage disease caused by a gene defect in the SGSH gene, producing the defective enzyme N-sulfoglucosamine sulfohydrolase. Children with MPSIIIA, accumulate the substrate of SGSH, heparan sulphate, in all cells in the body, causing developmental delay, regression of previously acquired skills, hyperactivity, seizures and progressive cognitive decline. The disease is life-limiting, with death occurring typically within the second decade of life. MPSIIIA is unresponsive to allogeneic stem cell transplant, presumed because insufficient enzyme is delivered via cross correction from donor-derived engrafted cells, particularly in the brain. Autologous ex vivo hematopoietic stem cell gene therapy (HSC-GT) is an experimental treatment for MPSIIIA, with the insertion of a functional copy of the SGSH gene into the patient's own CD34+ stem cells prior to transplant, to allow overexpression of the missing SGSH enzyme. In our pre-clinical work, we tested a lentiviral vector containing the SGSH gene driven by the human CD11b (myeloid-specific) promoter in a mouse model of MPSIIIA. This lentiviral vector was used to transduce CD34+ stem cells before transplant into fully-myeloablated busulfan-treated animals. Six-months post-transplant, SGSH enzyme was detected in the brain, with normalised behavior and heparan sulfate levels. Transduction and transplant of human CD34+ stem cells into humanized NSG mice demonstrated stable engraftment with no evidence of viral shedding or transformational potential, supporting the translation of this work to the clinic. Study Design: This is a phase I/II open label study (NCT04201405/EudraCT#2019-002051-42) with primary outcomes of safety and tolerability and peripheral expression of SGSH activity in total leukocytes at 12 months. Secondary endpoints include neurocognition with measures including the Bayley Scales of Infant and Toddler Development. Patients will be followed for a minimum of 3 years. Five patients with severe MPSIIIA, aged 6 to 24 months, have been treated with HSC-GT as part of this trial, completing enrolment. An additional patient was treated off-trial, at 30 months old, on a compassionate use basis. All children underwent stem cell mobilization and peripheral collection of CD34+ cells, followed by transduction with the lentiviral vector and cryopreservation. Patients received myeloablative busulfan condition before infusion of the drug product. Trial Status and Results: Three trial patients have >18 months follow-up post-transplant, one patient has >12 months and one patient has >9 months, with the off-trial 'special' patient >36 months. Vector copy number of the IMP ranged from 1.19 to 8.91 copies/cell, with a cell dose between 4.3 to 22.7x106 CD34+/kg. Engraftment was rapid with median time to neutrophil, platelet and red cell engraftment of 19, 28 and 25 days, respectively. In all patients, engraftment is sustained to date, with supra-physiological levels of SGSH enzyme measurable in leukocytes (38-91-fold above median normal range at one-month post-transplant; see Figure A). Supra-physiological SGSH levels were also rapidly detected in CD15+ lineages, plasma and bone marrow. CSF SGSH levels were within or above normal range by 6-months post-transplant. Abnormal heparan sulfate levels at baseline were rapidly reduced in both urine (>90%) and plasma (82%, see Figure B). Data from the specials patient, continues to show supra-physiological biochemical data and neurocognitive outcomes at 36 months post-transplant indicating an improved phenotype compared to MPSIIIA natural history. Neurocognitive assessments of trial patients continue and early outcomes will be presented suggesting an alteration in the neurologic phenotype of the disease in one patient, whilst three patients are currently within the normal DQ range but require longer follow-up. All trial patients show an improvement in SGSH expression in leukocytes and other lineages at early time points compared to that of the specials patient. Conclusions: Treatment with ex-vivo autologous HSC-GT is generally well tolerated and delivers supra-physiological levels of enzyme throughout the body. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Long-term follow-up of autologous peripheral blood hematopoietic stem cell transplantation for refractory lupus nephritis-a series study of 20 patients.

Autologous hematopoietic cell transplantation (ASCT) improves immunologic homeostasis in autoimmune diseases. ASCT-treated refractory lupus nephritis (LN) has been reported. Nevertheless, the long-term outcome of patients with refractory LN after ASCT remains unknown. This study reports the outcomes of 20 refractory lupus patients with 10-year of follow-up after receiving ASCT. Twenty-two patients with LN refractory to immunosuppressive therapy were enrolled. Twenty patients were examined closely and two cases died within 100 days after ASCT. Hematopoietic cell mobilization with cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) was followed by collection of CD34+ positively selected cells. The conditioning regimen consisted of intravenous cyclophosphamide, rabbit antithymocyte globulin, methylprednisolone, and G-CSF. All immunosuppressive therapies were discontinued at the start of mobilization and corticosteroids were tapered rapidly after ASCT. Data was collected from 22 patients with refractory LN treated by ASCT. 59% were female, duration of lupus before ASCT was 46 (33-71) months, and median duration of follow-up after ASCT was 89.5 (56-108) months. 20 long-term followed up patients had an average follow-up time of 92 months (63.25-109.5). Eighteen patients achieved complete remission, one patient reached partial remission, one patient without remission started peritoneal dialysis at month 12, and one patient received short-term renal replacement therapy before ASCT started hemodialysis at 84 months after transplantation. Nine patients relapsed 10 times during the follow-up, and three patients received rituximab. Two patients relapsed during pregnancy after complete response and the Apgar scores of infants were 9 and 10, respectively. All nine patients received glucocorticoids and immunosuppressive medication after relapse and responded again. The 10-year overall survival, 10-year disease-free survival rate, and 10-year renal survival were 100%, 35%, and 90%, respectively. The rate of relapse was 45%. Complications included hypocytosis, infection, B-type insulin resistance syndrome, and monoclonal immunoglobulinemia. This study suggests ASCT is effective and safety in treating refractory LN and is beneficial to improve their long-term outcomes.

A comparison of four leukapheresis methods to harvest an optimal dose of CD34+ cells: A single center experience

Chemokine receptor CXCR4 antagonist plerixafor (Px) as well as high volume (HV) leukapheresis have been shown to reduce hematopoietic stem progenitor cell (HSPC) mobilization failure rates. However, no direct comparisons of such methods currently exists. We compared the HSPC collection yield based on basal peripheral blood CD34+ cell numbers in patients diagnosed with multiple myeloma or non-Hodgkin's lymphoma undergoing autologous stem cell transplantation in a retrospective chart review. The leukapheresis methods used included HV versus regular volume (RV) with or without Px. There were 116 patients in the study group while the historical control group had 34 patients. Control group underwent RV leukapheresis without Px. Addition of Px or HV in the study group failed to display significant improvement in CD34+ cell collection yield; however, when basal CD34+ cell numbers were taken into account, both Px + RV and HV without Px increased CD34+ cell collection yield. The collection failure rates of HV without Px group were comparable to Px + RV when the basal CD34+ cell numbers were over 20/μl. Of interest, multivariate linear regression analysis did not detect any significant difference between HV versus Px + RV or other leukapheresis methods in CD34 yields or collection failure rates from a single collection after controlling for other factors (sex, age, or underlying disease). In multivariate analysis, pre apheresis CD34+ cell number was significantly and positively associated with the CD34+ cell yields from a single apheresis. In our studies, the majority of patients can be rescued without Px by HV alone as a potential cost saving approach. In summary, trend in our studies reflects that both Px and HV are capable of reducing the mobilization failure rates except the poorest mobilizers, which will need to be validated in larger studies.

PB2195: MOBILIZATION WITH CYTARABINE AND GRANULOCYTE COLONY STIMULATING FACTOR (G-CSF) GIVES BETTER YIELD THAN MOBILIZATION WITH G-CSF ALONE OR COMBINED WITH CYCLOPHOSPHAMIDE

Background: Patients with multiple myeloma are poor mobilizers and often require multiple cytapheresis procedures. Most popular mobilization regimens are with G-CSF given as a sole treatment or in combination with cyclophosphamide. Recently, several reports indicated that higher yields could be obtained following chemomobilization with cytarabine and G-CSF. Aims: Our aim was to compate the effectiveness of chemomobilization with cytarabine and G-CSF with the other regimens which we have used. Methods: Patients received 2x400mg/m2 cytarabine for two days, followed by 5mcg/kg G-CSF two days after for at least nine days. Cytapheresis was initiated with WBC count above 5x109/L, PLT count above 30x109/L and CD34+ cell count above 20/µl. Results of this group of patients were compared with results from a historic group of myeloma patients harvested between 2018 and 2020. Results: The new regimen showed markedly higher initial counts of CD34+ cells resulting in significantly better average yields (12.6x10^6/kg for the cytarabine + G-CSF group; 3.98 x10^6/kg for the G-CSF group and 4.998 x10^6/kg for the Cyclophosphamide+ G-CSF group). Summary/Conclusion: Compared with other hematological malignancies, patients with multiple myeloma are hard to mobilize for collection of sufficient CD34+ cells. Possible explanations are advanced age and bone marrow involvement. Chemomobilization with cytarabine and G-CSF seem to overcome poor mobilization and collection yields for this patient group.

Clinical features of methods for collecting hematopoietic stem cells in patients with malignant neoplasms weighing up to 15 kg and early age

Relevance. Autologous hematopoietic stem cell transplantation (auto-HSCT) is an integral part of the treatment of patients with high-risk malignancies. However, carrying out the mobilization and collection of hematopoietic stem cells (HSC) for patients weighing up to 15 kg is a complex task that requires a special approach and multidisciplinary interaction.The purpose of the study is to present the experience of collecting HSC in young children weighing up to 15 kg at the Research Institute of Pediatric Oncology and Hematology of the Federal State Budgetary Institution N.N. Blokhin National Medical Research Centre of Oncology, Ministry of Health of Russia.Materials and methods. The study included 30 patients weighing up to 15 kg who received treatment from January 2020 to May 2021 at the Research Institute of Pediatric Oncology and Hematology of the Federal State Budgetary Institution N.N. Blokhin National Medical Research Centre of Oncology, Ministry of Health of Russia. Median age was 30.6 (12–48) months, median body weight was 12.2 (7.8–15) kg. Apheresis in children weighing up to 15 kg was performed in the resuscitation and intensive care unit with the condition of pre-filling the cell separator circuit with a donor irradiated erythrocyte suspension to prevent hypovolemic complications. Thirty two apheresis was performed on a cell separator of the “Spectra Optia” type. To mobilize HSC, preparations of granulocyte colony-stimulating factor with the main active ingredient filgrastim were used.Results. Twenty eight HSC apheresis procedures were successful on the first attempt, 2 patients underwent repeated apheresis (a total of 32 procedures were performed). The median number of CD34+ cells obtained was 13.9 × 106/kg (0.04–92.0 × 106/kg), and the median apheresis duration was 251 (160–415) min. In 2 children during the procedure, an immediate organization of repeated venous access was required.Conclusions. Performing HSC apheresis in children weighing up to 15 kg and young children is a safe and effective technique with the participation of a multidisciplinary team. The apheresis algorithm proposed by us makes it possible to carry out a high-quality collection of CD34+ cells, sufficient for auto-HSCT.

Are we choosing mobilization regimens for autologous stem cell transplantation in multiple myeloma wisely: A single center comparison of GCSF+/-plerixafor vs cyclophosphamide/GCSF+/-plerixafor.

Autologous stem cell transplantation (ASCT) is a standard consolidation treatment for eligible patients with multiple myeloma (MM). There is no standardized mobilization regimen for collection of CD34+ stem cells, which is crucial to the success of ASCT. Cyclophosphamide/GCSF is an effective regimen, although reported associated toxicities include risk of febrile neutropenia (FN). Since plerixafor was introduced in Canada, this mobilization agent has been increasingly used as needed with GCSF at Kingston Health Science Centre (KHSC), with elimination of cyclophosphamide. This single center, retrospective, quality improvement study evaluates mobilization and ASCT outcomes of MM patients who had undergone stem cell mobilization at KHSC with cyclophosphamide/GCSF+/-plerixafor without antibiotics, cyclophosphamide/GCSF+/-plerixafor with antibiotics, and GCSF+/-plerixafor without antibiotics. A retrospective chart review was conducted evaluating 137 patients. The primary outcome measure was FN rates with mobilization. Balancing measures include CD34+ cell collected, plerixafor usage, days of apheresis and transplant outcomes. Chi-square, ANOVA, or Kruskal-Wallis methods were used to test statistical significance where appropriate. Our study noted a higher total and day one CD34+ count in the two groups utilizing cyclophosphamide in mobilization. All nine cases of FN occurred in these two groups (P < .05). Addition of antibiotics decreased, but did not eliminate risk of FN. There were no significant differences in the rate of plerixafor usage and number of apheresis days. Difference in transplant outcomes, including engraftment and transfusion support, were statistically but not clinically significant. A larger sample size may be needed to explore this fully. There was no significant difference in length of transplant hospital stay. The elimination of cyclophosphamide from mobilization regimens for MM appears to significantly reduce FN rates, without increasing balancing measures such as total number of apheresis days, plerixafor usage, duration of transplant hospitalization or mortality outcomes.

Long-term follow-up after lymphodepleting autologous haematopoietic cell transplantation for treatment-resistant systemic lupus erythematosus.

Autologous haematopoietic cell transplantation (AHSCT) improves immunologic dysfunction in patients with SLE. However, the curative potential of this therapy remains uncertain. This study reports outcomes in SLE patients receiving a lymphodepleting, reduced intensity regimen for AHSCT in SLE. Eight patients with SLE refractory to treatment, including i.v. cyclophosphamide (CYC), were enrolled. Five had LN and three CNS involvement as primary indications for transplant. Haematopoietic cell mobilization with CYC, G-CSF and rituximab was followed by collection of CD34+ positively selected cells. The conditioning regimen consisted of concurrent administration of CYC, fludarabine and rituximab. All immunosuppressive medications were discontinued at the start of mobilization and CS were rapidly tapered after the transplant. Five of eight patients achieved a complete response, including a decline in the SLEDAI to zero, which was sustained in four patients for a median of 165 months (range 138-191). One patient achieved a partial response, which was followed by relapse at month 18. Two patients with nephritis and underlying comorbidities in most organs had early deaths from infection and multiorgan failure. AHSCT resulted in profound lymphodepletion, followed by expansion of Treg cells and repopulation of naive T and B cells. Patients with a complete response showed a sustained suppression of the SLE-associated IFN-induced gene signature, marked depletion of memory and plasmablast B cells and resultant sustained elimination of anti-dsDNA antibody. Durable clinical and serologic remissions with suppression in the IFN gene signature can be achieved in refractory SLE following lymphodepleting AHSCT. ClinicalTrials.gov, https://clinicaltrials.gov, NCT00076752.

High D-index during mobilization predicts poor mobilization of CD34+ cells after anti-lymphoma salvage chemotherapy.

Performing stem cell collection after mobilization chemotherapy was a well-balanced strategy between anti-tumor effect and efficient collection of CD34+ cells, but deep and prolonged nadir exposed patients to risk of febrile neutropenia. Febrile neutropenia was known to be associated with lower yields of CD34+ cells, but quantitative data referring to association between yields of CD34+ cells and severity of neutropenia was lacking. We hypothesized that D-index, which was developed for quantitative evaluation of severity of neutropenia especially in the field of hematologic malignancies, could predict yields of CD34+ cells. We performed a single center, retrospective analysis of patients with relapsed or refractory aggressive lymphoma who were mobilized with ESHAP or modified ESHAP. We evaluated the association between yields of CD34+ cells at first apheresis and D-index. Thirty-six patients were included, and we demonstrated that yields of CD34+ cells from patients with higher D-index were significantly lower than those from patients with lower D-index. Multivariate linear regression analysis and logistic regression analysis also demonstrated the significant predictive power of D-index. Further, D-index was significantly correlated to platelet count before starting mobilization chemotherapy. Platelet count was known to predict yields of CD34+ cells, and combination of platelet count and D-index could identify patients with lowest CD34+ yields. D-index could predict yields of CD34+ cells and it seemed that its predictive power was not less than that of platelet count. Prospective studies including more heterogeneous patients were needed to validate our study.

Meloxicam with Filgrastim may Reduce Oxidative Stress in Hematopoietic Progenitor Cells during Mobilization of Autologous Peripheral Blood Stem Cells in Patients with Multiple Myeloma.

Autologous stem cell transplantation (ASCT) is a potentially curative therapy but requires collection of sufficient blood stem cells (PBSC). Up to 40 % of patients with multiple myeloma (MM) fail to collect an optimum number of PBSC using filgrastim only and often require costly plerixafor rescue. The nonsteroidal anti-inflammatory drug meloxicam mobilizes PBSC in mice, nonhuman primates and normal volunteers, and has the potential to attenuate mobilization-induced oxidative stress on stem cells. In a single-center study, we evaluated whether a meloxicam regimen prior to filgrastim increases collection and/or homeostasis of CD34+ cells in MM patients undergoing ASCT. Mobilization was not significantly different with meloxicam in this study; a median of 2.4 × 106 CD34+ cells/kg were collected in the first apheresis and 9.2 × 106 CD34+ cells/kg were collected overall for patients mobilized with meloxicam-filgrastim, versus 4.1 × 106 in first apheresis and 7.2 × 106/kg overall for patients mobilized with filgrastim alone. CXCR4 expression was reducedon CD34+ cells and a higher CD4+/CD8+ T-cell ratio was observedafter mobilization with meloxicam-filgrastim. All patients treated with meloxicam-filgrastim underwent ASCT, with neutrophil and platelet engraftment similar to filgrastim alone. RNA sequencing of purified CD34+ cells from 22 MM patients mobilized with meloxicam-filgrastim and 10 patients mobilized with filgrastim only identified > 4,800 differentially expressed genes (FDR < 0.05). Enrichment analysis indicated significant attenuation of oxidative phosphorylation and translational activity, possibly mediated by SIRT1, suggesting meloxicam may counteract oxidative stress during PBSC collection. Our results indicate that meloxicam was a safe, low-cost supplement to filgrastim mobilization, which appeared to mitigate HSPC oxidative stress, and may represent a simple means to lessen stem cell exhaustion and enhance graft quality.

Risk of Engraftment Syndrome after Autologous Stem Cell Transplantation for Multiple Myeloma Increases with Age and Lower Dose of CD34+ Cells, but Is Not Impacted By Immunomodulatory Chemotherapy

Background: Engraftment syndrome (ES) has been observed post autologous hematopoietic stem cell transplantation (ASCT) in patients with multiple myeloma (MM), and may require treatment with immunosuppressive therapies and prolonged hospitalization. Risk factors for the development of ES have not been clearly defined, with conflicting reports as to the role of CD34+ cell dose and pre-ASCT therapy. Defining risk factors could lead to the development of strategies to mitigate the risk of ES.Methods : A cohort of 496 patients who received 596 ASCT for MM between January 2005 and December 2015 was reviewed. ES was defined as a combination of at least 2 symptoms not attributed to other causes including non-infectious fever, diarrhea, skin rash, pulmonary infiltrates or hepatic dysfunction starting from 3 days prior to 10 days post-engraftment. Potential risk factors for the development of ES were analyzed, including age, pre-ASCT therapy, mobilization regimen, pre-ASCT dialysis or radiation therapy, number of CD34+ cells infused, time from diagnosis to transplantation, and disease status at the time of transplantation. Pre-ASCT therapies included lenalidomide (Len), bortezomid (Bor) and Carfilzomib (Car). High risk disease (HRD) was defined as t(14;16), t(14;20), del 17p, t(4;14) or 1q gain by FISH, del 13q, monosomy 13 or hypodiploidy by standard cytogenetics, or high risk signature gene expression profiling. Kaplan Meier and Cox proportional hazard methods were employed.Results: The median age at ASCT was 61 years (range 39-84) and 58% were male. There were 153 incidents of ES by defined criteria, with 123 patients requiring corticosteroids, 6 patients requiring the addition of tacrolimus, and one patient death attributed to ES. Pre-ASCT radiation therapy, time from diagnosis to transplantation and disease status at the time of transplantation were not significantly associated with the development of ES. Patients who received Len (p=0.8840), Bor (p=0.2458), Len and Bor combination (0.6907), or Car (p=0.6818) did not have increased risk of ES. Cyclophosphamide (Cy) for mobilization resulted in higher collection of CD34+ cells, but was not significantly associated with the risk of ES (p=0.6095). The median CD34+ cell dose infused for patients with ES was 5.22 x 10e6/kg versus 5.91 x 10e6/kg for patients without ES. Higher doses of CD34+ cells infused were protective against ES (P=0.0030). Patients with HRD had a significantly higher risk for developing ES, vs patients with standard risk disease (P=0.0041). Patients age 60 and older at the time of ASCT were more likely to develop ES (p=0.0249), and the incidence of ES increased with age up to age 75 . OS by univariate analysis was worse for patients who experienced ES (p=0.0.49). In multivariate analysis, stratified by number of transplants, patients with ES had lower overall survival than patients without ES (p=0.0179) when accounting for HRD, progression and response at ASCT.Conclusions: Pre-ASCT chemotherapy with Bor, Car and/or Len has no effect on the incidence of ES. Stem cell mobilization regimen did not impact the incidence of ES, but higher CD34+ cell doses are protective against ES. Patients without ES have improved overall survival. Older patients are at greater risk for ES, and the risk increases along the age continuum up to age 75. Infusing higher doses of CD34+ cells could be a strategy to mitigate the risk of ES in older patients. [Display omitted] DisclosuresMcKiernan:Novartis: Speakers Bureau. Siegel:Merck: Consultancy; Celgene, Takeda, Amgen Inc, Novartis and BMS: Consultancy, Speakers Bureau. Vesole:Takeda: Speakers Bureau; Celgene: Speakers Bureau. Skarbnik:Novartis: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau; Genentech: Speakers Bureau; Abbvie: Other: Ad board, Speakers Bureau. Biran:Celgene, Amgen: Consultancy, Speakers Bureau; Takeda: Speakers Bureau. Richter:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Speakers Bureau; Janssen: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Pecora:COTA: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties; Caladrius Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Goy:Genentech: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics / J&J: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.