Apheresis Cycles Research Articles

Repeated lipoprotein apheresis and immune response: Effects on different immune cell populations.

Atherosclerosis is considered a chronic inflammation of arterial vessels with the involvement of several immune cells causing severe cardiovascular diseases. Lipoprotein apheresis (LA) improves cardiovascular conditions of patients with severely disturbed lipid metabolism. In this context, little is known about the impact of LA on various immune cell populations, especially over time. Immune cells of 18 LA-naïve patients starting weekly LA treatment were analyzed before and after four apheresis cycles over the course of 24 weeks by flow cytometry. An acute lowering effect of LA on T cell and natural killer (NK) cell subpopulations expressing CD69 was observed. The non-classical and intermediate monocyte subsets as well as HLA-DR+ 6-sulfo LacNAc+ monocytes were significantly reduced during the apheresis procedure. We conclude that LA has the capacity to alter various immune cell subsets. However, LA has mainly short-term effects than long-term consequences on proportions of immune cells.

Preliminary Safety and Efficacy Results from Precizn-1: An Ongoing Phase 1/2 Study on Zinc Finger Nuclease-Modified Autologous CD34+ HSPCs for Sickle Cell Disease (SCD)

▪IntroductionSickle cell disease (SCD) is caused by pathologic variants in both alleles of the β-globin gene, affecting ~100,000 patients in the US (Strouse. Handb Clin Neurol 2016;138:311-24). Elevated fetal hemoglobin (HbF) levels ameliorate symptoms and improve survival in patients with SCD (Hebert. Am J Hematol 2020;95:1235-45). SAR445136 (BIVV003) is a novel therapeutic product comprising autologous CD34+ HSPCs modified ex vivo by zinc finger nucleases (ZFN) and targeting the BCL11A gene erythroid-specific enhancer (ESE) to increase endogenous HbF production.MethodsPRECIZN-1 (NCT03653247) is an ongoing first-in-human, open label, single arm, multi-site study evaluating safety and tolerability of SAR445136 (n=8; aged 18-40 years), with severe SCD across 6 US sites. Eligible subjects underwent mobilization and apheresis with plerixafor 240 ug/kg/day for up to 3 days to collect autologous CD34+ HSPCs to achieve a minimum of 10 × 10 6 CD34+ HSPC/kg for manufacturing of the SAR445136 dose. Additional apheresis cycles were allowed to achieve the minimum cell dose and rescue aliquots. Autologous HSPCs were transfected ex vivo with ZFN mRNAs targeting the ESE region of the BCL11A locus to manufacture SAR445136. A single IV infusion of 3-20 × 10 6 CD34+ HSPC/kg was administered at least 72 hours after the final busulfan myeloablation dose. Subjects were monitored for stem cell engraftment and hematopoietic recovery, adverse events (AEs), clinical and laboratory hemolysis markers, total Hb and HbF, percentage of F cells and sickle-cell related events post-SAR445136 infusion. Health-related quality of life (HRQoL) was assessed via the PROMIS-57 survey at screening, Weeks 26 and 52, and early termination visit.ResultsOf the 7 subjects that underwent mobilization and apheresis to date (25 June 2021), 5 achieved successful target yields ranging from 3.4-13.8 x 10 6 CD34+ HSPC/kg per apheresis day (mean: 6.49 x10 6 CD34+ HSPC/kg per apheresis day) in one apheresis cycle (4.45-10.9 x 10 6 CD34+ HSPC/kg per 2-day cycle). One subject failed to mobilize; one discontinued due to intercurrent cholangitis. Baseline patient characteristics of the 4 patients infused are in Table 1.Pre-apheresis peripheral blood WBC ranged from 23.2-36.9 x 10 3/μL (mean: 28.7 x 10 3/μL) and % CD34+ was 0.09-0.36% (0.22%) with absolute CD34+ counts of 20-80/μL (mean: 60/μL). Four of the mobilized subjects were successfully infused with SAR445136 at a single dose ranging from 3.2-9.7 x 10 6 CD34+ HSPC/kg (mean: 5.17 x 10 6 CD34+ HSPC/kg). All 4 subjects engrafted with a median time to neutrophil and platelet recovery of 21.5 and 24.5 days, respectively. No rescue doses were required.All 4 patients improved clinically since SAR445136 infusion, with no recurrence of previous vaso-occlusive crises (VOCs). Total Hb stabilized at 9-10 g/dL by week 26 post SAR445136 infusion along with improvements in the clinical markers of hemolysis in all 4 subjects. Percent HbF levels were 1-11% at screening, increasing to 15-29% by Week 13 in all 4 subjects, to 14-39% by Week 26 in the 3 subjects with at least 26 weeks follow up; and persisting at 35% in 1 subject with 65 weeks follow up (Figure 1). Percent F cells increased to 49-94% in 3 subjects with at least 26 weeks follow up, persisting at 90% in 1 subject with 65 weeks follow up. The fourth subject had 87.5% F cells at 13 weeks follow up.Although preliminary, a trend of improvement exceeding the proposed minimally clinically important difference in all PROMIS-57 HRQoL domains except sleep disturbance was observed in the 3 subjects with 26 weeks follow up, whose scores were “worse” than the norm at baseline (≤2 points per domain).SAR445136 was generally well tolerated with no infusion related reactions. The AEs reported were consistent with plerixafor mobilization and busulfan myeloablation therapy. No AEs or SAEs were reported as related to SAR445136.ConclusionsAs of 25 June 2021, these preliminary proof-of-concept efficacy and safety results confirm the potential therapeutic value of ZFN-mediated modification of the BCL11A ESE region and SAR445136 infusion to address current unmet needs of patients with SCD. All 4 infused patients had no SCD related events including VOCs following SAR445136 infusion, as well as increases in total Hb, HbF, and %F cells, and clinical improvements in PROMIS-57 domains. SAR445136 is generally well tolerated in the 4 subjects infused to date, with no related AEs or SAEs reported. [Display omitted] DisclosuresAbedi: BMS/Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Seattle Genetics: Speakers Bureau; Abbvie: Speakers Bureau. Galeon: Sanofi: Current Employment. Reiner: Sanofi: Current Employment. Smith: Sanofi: Current Employment. Wang: Sanofi: Current Employment. Ramezi: Sanofi: Current Employment. Rendo: Sanofi: Current Employment, Other: May hold shares and/or stock options . Walters: AllCells, Inc: Consultancy; Vertex pharmaceuticals: Consultancy; Ensoma, Inc.: Consultancy; BioLabs, Inc: Consultancy.

Hematopoietic, Immune Recovery and Outcomes after Autologous Stem Cell Transplantation Following Plerixafor Plus G-CSF Versus Chemotherapy and G-CSF Based Mobilization in Pediatric Patients

Background: High-dose chemotherapy (HDC) and autologous stem-cell transplantation (ASCT) has shown survival benefits for chemo-sensitive high risk pediatric solid tumors. Collection of sufficient hematopoietic stem cells is required for ASCT. Plerixafor, a CXCR4 receptor antagonist, has been used when granulocyte colony-stimulating factor (G-CSF) and chemotherapy based (conventional) mobilization may not enable us to collect enough cells, especially in recurred or heavily treated patients. The experiences of plerixafor in pediatric patients are lacking as compared with adults, and immune reconstitution and outcomes in pediatric patients after ASCT with plerixafor based mobilization have not been reported in the literature as far as we have known. Therefore, we aimed to compare engraftment, hematopoietic and immune recovery and transplantation outcomes after ASCT between plerixafor plus G-CSF based and conventional mobilization group in pediatric patients.Methods: Propensity score matching (PSM) by optimal method with 1:1 ratio was performed to determine the control group. Age, sex, diagnosis, transplantation year, conditioning regimen, and number of transplantation were used as matching variables. We evaluated available parameters such as the day of neutrophil and platelet engraftment, absolute neutrophil counts (ANCs), absolute lymphocyte counts (ALCs), platelet and hemoglobin counts and lymphocyte subsets (CD3, CD4, CD8 [T cell] counts). Mann-Whitney U test was used to compare between two groups.Results: There were a total of 233 (21 plerixafor plus G-CSF based and 212 conventional mobilization group) patients who underwent HDC and ASCT in Seoul National University Children's Hospital between 2009 and 2016. By creating matched samples using PSM, 42 (21 plerixafor plus G-CSF based and 21 conventional mobilization group) patients were analyzed. The diagnoses were osteosarcoma in 14, brain tumor in 10, lymphoma in 6, neuroblastoma in 5, Ewing sarcoma in 4 and retinoblastoma in 3 patients. We used plerixafor plus G-CSF in patients who previously failed peripheral blood stem cell mobilization by chemotherapy and G-CSF. Patients received G-CSF (10 μg/kg) for 4 days, without prior chemotherapy. Then plerixafor (240 ug/kg) and G-CSF (10 ug/kg) were administered subcutaneously, at 10 and 2 hours before each apheresis. All 21 patients using plerixafor were mobilized successfully, and the median number of CD34+ cells were 10.65 (range 2.35-28.97) × 106/kg after 1 to 4 cycles of apheresis without serious complications. Fifty six ASCTs were performed, including 14 tandem transplantation. The median age at ASCT was 6 (range 3.7-22.4) years. All patients in conventional mobilization group achieved engraftment, but 2 patients in plerixafor plus G-CSF based mobilization group died due to acute respiratory distress syndrome before platelet engraftment and 1 patient died of sudden cardiac arrest before neutrophil and platelet engraftment. The engraftment tended to be faster in conventional mobilization group, but there was no statistically significant difference except for the day of ANC more than 0.5 × 109/L for 3 consecutive days (p=0.040). The ALC was lower in plerixafor plus G-CSF based mobilization group at one and six months after ASCT, respectively (p <0.001, p=0.041). The CD3, CD4 and CD8 count was lower in plerixafor plus G-CSF based mobilization group at one month after ASCT, respectively (p <0.001, p=0.007, p<0.001). The CD8 count was lower in plerixafor plus G-CSF based mobilization group (p=0.016), but the CD3 and CD4 count showed no statistical significant between-group differences at one year after ASCT, respectively (p=0.098, p=0.473). There was no significant between-group differences of overall survival (85.2% in plerixafor plus G-CSF based and 68.8% in conventional mobilization group, p=0.496) with a median follow-up duration of 22.7 (range 0.1-90.2) months.Conclusion: Hematopoietic and immune recovery tended to be slower in plerixafor plus G-CSF based mobilization group, but was done to a similar extent over time. In addition, transplant outcomes are similar between two groups. Our study suggests that plerixafor could be used safely and enabled more patients to procced to successful ASCT in pediatric patients. DisclosuresNo relevant conflicts of interest to declare.

Disease severity impacts plerixafor-mobilized stem cell collection in patients with sickle cell disease

Recent studies suggest that plerixafor mobilization and apheresis in patients with sickle cell disease (SCD) is safe and can allow collection of sufficient CD34+ hematopoietic stem cell (HSC) collection for clinical gene therapy applications. However, the quantities of plerixafor-mobilized CD34+ cells vary between different SCD patients for unknown reasons. Twenty-three participants with SCD underwent plerixafor mobilization followed by apheresis, processing, and HSC enrichment under a phase 1 safety and efficacy study conducted at 2 institutions. Linear regression or Spearman's correlation test was used to assess the relationships between various hematologic and clinical parameters with total CD34+ cells/kg collected. Median CD34+ cells/kg after 2 or fewer mobilization and apheresis cycles was 4.0 × 106 (range, 1.5-12.0). Similar to what is observed generally, CD34+ yield correlated negatively with age (P < .001) and positively with baseline (P = .003) and preapheresis blood CD34+ cells/µL (P < .001), and baseline white blood cell (P = .01) and platelet counts (P = .03). Uniquely for SCD, CD34+ cell yields correlated positively with the number of days hydroxyurea was held (for up to 5 weeks, P = .01) and negatively with markers of disease severity, including hospitalization frequency within the preceding year (P = .01) and the number of medications taken for chronic pain (P = .002). Unique SCD-specific technical challenges in apheresis were also associated with reduced CD34+ cell collection efficiency and purification. Here, we describe factors that impact plerixafor mobilization success in patients with SCD, confirming known factors as described in other populations in addition to reporting previously unknown disease specific factors in patients with SCD. This trial was registered at www.clinicaltrials.gov as #NCT03226691.

Predictive factors of poor blood collecting flow during leukocyte apheresis for cellular therapy.

Leukocyte apheresis is necessary in various cellular therapies. However, maintenance of a stable flow rate during leukocyte apheresis is often difficult, even in patients or donors without major problems. Despite this, predictive methods and evidence regarding the reality of the situation are limited. We conducted a retrospective analysis involving adult patients who required leukocyte apheresis for the treatment of neoplasms using WT1-pulsed dendritic cell vaccine. Monocytes were separated from apheresis products to obtain dendritic cells. All the patients were pre-evaluated based on laboratory and chest X-ray findings and subjected to an identical apheresis procedure. The occurrence of poor blood collecting flow during leukocyte apheresis was monitored, and the frequency, clinical information, and associated risk factors were analyzed. Among 160 cases, poor blood collecting flow was observed in 53 cases (33.1%) in a median time of 54 min (range, 2-127 min) post-initiation of leukocyte apheresis. Owing to difficulty in obtaining higher collecting flow, a longer procedure time was required, and in some cases, the scheduled apheresis cycles could not be completed. Consequently, the number of harvested monocytes was low. Multivariable analysis indicated that female patients have an increased risk of poor inlet flow rate. Furthermore, prolonged QT dispersion (QTD) calculated using Bazett's formula was found to be a risk factor. Although the patients did not present any major problems during leukocyte apheresis, poor blood collecting flow was observed in some cases. Sex and pre-evaluated QTD might be useful predictors for these cases; however, further prospective evaluation is necessary.

Immunoadsorption and Plasma Exchange in Seropositive and Seronegative Immune-Mediated Neuropathies.

The inflammatory neuropathies are disabling conditions with diverse immunological mechanisms. In some, a pathogenic role for immunoglobulin G (IgG)-class autoantibodies is increasingly appreciated, and immunoadsorption (IA) may therefore be a useful therapeutic option. We reviewed the use of and response to IA or plasma exchange (PLEx) in a cohort of 41 patients with nodal/paranodal antibodies identified from a total of 573 individuals with suspected inflammatory neuropathies during the course of routine diagnostic testing (PNAb cohort). 20 patients had been treated with PLEx and 4 with IA. Following a global but subjective evaluation by their treating clinicians, none of these patients were judged to have had a good response to either of these treatment modalities. Sequential serology of one PNAb+ case suggests prolonged suppression of antibody levels with frequent apheresis cycles or adjuvant therapies, may be required for effective treatment. We further retrospectively evaluated the serological status of 40 patients with either Guillain-Barré syndrome (GBS) or chronic inflammatory demyelinating polyneuropathy (CIDP), and a control group of 20 patients with clinically-isolated syndrome/multiple sclerosis (CIS/MS), who had all been treated with IgG-depleting IA (IA cohort). 32 of these patients (8/20 with CIDP, 13/20 with GBS, 11/20 with MS) were judged responsive to apheresis despite none of the serum samples from this cohort testing positive for IgG antibodies against glycolipids or nodal/paranodal cell-adhesion molecules. Although negative on antigen specific assays, three patients’ pre-treatment sera and eluates were reactive against different components of myelinating co-cultures. In summary, preliminary evidence suggests that GBS/CIDP patients without detectable IgG antibodies on routine diagnostic tests may nevertheless benefit from IA, and that an unbiased screening approach using myelinating co-cultures may assist in the detection of further autoantibodies which remain to be identified in such patients.

One-Day Low-Dose Etoposide Is an Effective Chemomobilization Regimen with Minimal Toxicity for Autologous Stem Cell Transplantation in Patients with Multiple Myeloma: A Multicenter Study from Tertiary Hospitals in Korea

PurposeAutologous stem cell transplantation (ASCT) is widely used as a part of induction treatment for transplantation-eligible patients with multiple myeloma. For successful ASCT, mobilizing hematopoietic stem cells from bone marrow to peripheral blood is essential because collecting a sufficient number of stem cells using apheresis is mandatory. As a method for mobilization, chemomobilization consisting of high-dose chemotherapy plus granulocyte-colony stimulating factor (G-CSF) or G-CSF alone (G-mobilization) has been used. However, the mobilization failure still remains a problematic issue. Given repeated mobilization attempts increase medical costs and the risk of morbidity related with apheresis, the mobilization process should be efficient. Chemomobilization is more effective than G-mobilization, however, chemomobilization has the risk of complication such as febrile neutropenia or chemotherapy-induced second malignancy. Thus, we compared the efficacy and safety of our new chemomobilization regimen, one-day low-dose etoposide with that of two-day low-dose etoposide, one-day high-dose cyclophosphamide, and G-mobilization.MethodsWe retrospectively analyzed 234 patients who underwent ASCT for MM between 2008 and 2018 in four tertiary hospitals in Korea. One-day low-dose etoposide regimen (E1) was the intravenous (IV) administration of etoposide (375 mg/m2) over 4 hours whereas two-day low-dose etoposide (E2) was the same dose of etoposide on 1st and 2nd day in outpatient clinic. G-CSF administration was started around on 10th day until the end of collection. In G-mobilization regimen (G), the injection of G-CSF was started four days (day -4) before initiation of apheresis (day 0), and G-CSF once a day was maintained untill the end of collection. One-day high-dose cyclophosphamide regimen (C) was the IV administration of cyclophosphamide (3.5 g/m2) on 1st day and the daily injection of G-CSF from 2nd day until the end of stem cell collection. Peripheral blood stem cell collection was started when CD34-positive cells or hematopoietic progenitor cells were more than 5000/μL in peripheral blood, or white blood cell count was more than 5000/μL. In this study, we defined the ‘adequate mobilization’ as CD34-positive cells more than 4ⅹ106/kg, and ‘mobilization failure’ as a collected CD34-positive cells less than 2ⅹ106/kg. Neutrophil and platelet engraftment was defined as more than 500/μL and 20,000/μL on consecutive two days, respectively.Results31 patients received single dose etoposide (E1) between 2016 and 2018 whereas 28 patients received double dose etoposide (E2) between 2011 and 2018. The other two regimens were used in 105 (C, 2008-2015) and 70 patients (G, 2008-2017) according to physicians' decision. The comparison of four regimens showed the median CD34-positive cells of E1 regimen was 5.57ⅹ106/kg that was comparable to that of E2 and C (Table 1). The number of CD34-positive cells on 1st day of apheresis was 4.03ⅹ106/kg in E1 regimen, and it was higher than that of C and G (3.32 and 1.79ⅹ106/kg, respectively). As a result, E1 regimen achieved ‘adequate mobilization’ in 100% of patients (n=30) like E2 regimen (n=28, 100%). Mobilization failure did not occur in E1 and E2 regimens whereas 4-10% of patients experienced mobilization failure in C and G regimens (Table 1). All patients receiving E1 and E2 regimen but one patient in E1 could collect more than 4ⅹ106/kg of CD34-positive cells within three cycles of apheresis. The occurrence of febrile neutropenia was extremely lower in E1 regimen (7%) than E2 and C regimens (43% and 34%, respectively, p<0.001). Both neutrophil and platelet engraftment were the fastest in E1 (the median 9 days after ASCT, p<0.001).ConclusionsOne-day low-dose etoposide administration could be effective for chemomobilization in myeloma patients with reduced risk of complication compared to two-day low-dose etoposide, high-dose cyclophosphamide and G-mobilization. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Biofabrication of a novel leukocyte-fibrin-platelet membrane as a cells and growth factors delivery platform for tissue engineering applications.

Autologous platelet-rich hemocomponents have emerged as potential biologic tools for regenerative purpose, but their therapeutic efficacy still remains controversial. This work represents the characterization study of an innovative autologous leukocyte-fibrin-platelet membrane (LFPm), which we prepared according to a novel protocol involving multiple cycles of apheresis. The high content in fibrinogen gave to our hemocomponent the appearance of a manipulable and suturable membrane with high elasticity and deformation capacity. Moreover, being highly enriched with platelets, leukocytes, and monocytes/macrophages, the LFPm sustained the local release of bioactive molecules (platelet derived growth factor, vascular endothelial growth factor, interleukin-10, and tumour necrosis factor alpha). In parallel, the evaluation of stemness potential highlighted also that the LFPm contained cells expressing pluripotency and multipotency markers both at the messenger ribonucleic acid (NANOG, SOX2, THY1, NT5E, and ENG) and surface-protein level (CD44high /CD73+ /CD34+ /CD117+ /CD31+ ). Finally, biodegradation analysis interestingly showed a good stability of the membrane for at least 3weeks in vitro and 1week in vivo. In both cases, biodegradation was associated with progressive exposure of fibrin scaffold, loss/migration of cellular elements, and release of growth factors. Overall, collected evidence could shed some light on the regenerative effect that LFPms may exert after the autologous implant on a defect site.

Evaluation of Hematopoietic Stem Cell Mobilization Rates with Early Plerixafor Administration for Adult Stem Cell Transplantation

The addition of plerixafor to high-dose colony-stimulating growth factor has been shown to improve stem cell mobilization rates in autologous transplant patients with multiple myeloma and non-Hodgkin lymphoma. This study evaluates the change in administration time of plerixafor to determine if cell mobilization rates are similar between the US Food and Drug Administration–approved administration time of 11 hours before apheresis and an earlier administration time of 16 hours before apheresis. Medical records of patients age ≥ 18 years undergoing autologous stem cell transplantation requiring the use of plerixafor after at least 4 days of granulocyte colony-stimulating factor therapy to complete stem cell mobilization from January 1, 2010 through September 30, 2014 were retrospectively reviewed. The primary outcome was CD34+ cell mobilization success rates when plerixafor was administered 11 ± 2 hours (standard administration group) compared with 16 ± 2 hours before cell apheresis (early administration group), as defined as collection of ≥2 × 106 CD34+ cells/kg. Secondary outcomes included the number of plerixafor therapy days required to collect a total of ≥2 × 106 CD34+ cells/kg, the number of apheresis cycles required to achieve ≥2 × 106 CD34+ cells/kg, the median CD34+ cells/kg collected in each apheresis session, and the rates of reported adverse events that occurred in the standard administration time group compared with the early administration time group. Of the 197 patients included, 114 patients received plerixafor 11 ± 2 hours before apheresis and 83 patients received plerixafor 16 hours ± 2 hours before apheresis. Ninety-four percent of patients in the early administration group achieved successful stem cell mobilization compared with 81.6% in the standard administration group (P = .0111). The median number of plerixafor days to reach the collection goal of ≥2 × 106 CD34+ cells/kg was 1 day for each group (P = .323), and the median number of apheresis days to reach the collection goal was 2 days for the standard administration group compared with 1 day for the early administration group (P = .0156). Most adverse events were similar between the 2 groups except for fever, which occurred in 4.8% of the patients in the early administration group and none of the patients in the standard administration group. This study demonstrates plerixafor effectively mobilizes peripheral blood stem cells when given at an early administration time of 16 hours before apheresis compared with standard administration of 11 hours before apheresis. However, further prospective studies could strengthen these results.

Neuroregenerative potential of intravenous G-CSF and autologous peripheral blood stem cells in children with cerebral palsy: a randomized, double-blind, cross-over study

ObjectiveWe performed a randomized, double-blind, cross-over study to assess the neuroregenerative potential of intravenous granulocyte colony-stimulating factor (G-CSF) followed by infusion of mobilized peripheral blood mononuclear cells (mPBMCs) in children with cerebral palsy (CP).MethodsChildren with non-severe CP were enrolled in this study. G-CSF was administered for 5 days, then mPBMCs were collected by apheresis and cryopreserved. One month later (M1), recipients were randomized to receive either mPBMCs or a placebo infusion, and these treatment groups were switched at 7 months (M7) and observed for another 6 months (M13). We assessed the efficacy of treatment by evaluating neurodevelopmental tests, as well as by brain magnetic resonance imaging-diffusion tensor imaging (MRI-DTI) and 18F-fluorodeoxyglucose (FDG) brain positron emission tomography-computed tomography (PET-CT) scanning to evaluate the anatomical and functional changes in the brain.ResultsFifty-seven patients aged 4.3 ± 1.9 (range 2–10) years and weighing 16.6 ± 4.9 (range 11.6–56.0) kg were enrolled in this study. The administration of G-CSF as well as the collection and reinfusion of mPBMCs were safe and tolerable. The yield of mPBMCs was comparable to that reported in studies of pediatric donors without CP and patients with nonhematologic diseases. 42.6% of the patients responded to the treatment with higher neurodevelopmental scores than would normally be expected. In addition, larger changes in neurodevelopment test scores were observed in the 1 month after G-CSF administration (M0–M1) than during the 6 months after reinfusion with mPBMCs or placebo (M1–M7 or M7–M13). Patients who received G-CSF followed by mPBMC infusion at 7 months (T7 group) demonstrated significantly more neurodevelopmental improvement than patients who received G-CSF followed by mPBMC infusion at 1 month (T1 group). In contrast to the results of neurodevelopment tests, the results of MRI-DTI at the end of this study showed greater improvement in the T1 group. Although we observed metabolic changes to the cerebellum, thalamus and cerebral cortex in the 18F-FDG brain PET-CT scans, there were no significant differences in such changes between the mPBMC and placebo group or between the T1 and T7 group.ConclusionsNeurodevelopmental improvement was seen in response to intravenous G-CSF followed by mPBMC reinfusion, particularly to the G-CSF alone even without mPBMC reinfusion. Further studies using a larger number of mPBMCs for the infusion which could be collected by repeated cycles of apheresis or using repeated cycles of G-CSF alone, are needed to clarify the effect of mPBMC reinfusion or G-CSF alone (Trial registration: ClinicalTrials.gov, NCT02983708. Registered 5 December, 2016, retrospectively registered).

Aging Impairs Long-Term Hematopoietic Regeneration after Autologous Stem Cell Transplantation

Most of our knowledge of the effects of aging on the hematopoietic system comes from studies in animal models. In this study, to explore potential effects of aging on human hematopoietic stem and progenitor cells (HSPCs), we evaluated CD34+ cells derived from young (<35 years) and old (>60 years) adult bone marrow with respect to phenotype and in vitro function. We observed an increased frequency of phenotypically defined stem and progenitor cells with age, but no distinct differences with respect to in vitro functional capacity. Given that regeneration of peripheral blood counts can serve as a functional readout of HSPCs, we compared various peripheral blood parameters between younger patients (≤50 years; n = 64) and older patients (≥60 years; n = 55) after autologous stem cell transplantation. Patient age did not affect the number of apheresis cycles or the amount of CD34+ cells harvested. Parameters for short-term regeneration did not differ significantly between the younger and older patients; however, complete recovery of all 3 blood lineages at 1 year after transplantation was strongly affected by advanced age, occurring in only 29% of the older patients, compared with 56% of the younger patients (P = .009). Collectively, these data suggest that aging has only limited effects on CD34+ HSPCs under steady-state conditions, but can be important under consitions of chemotoxic and replicative stress.

Successful mobilization using a combination of plerixafor and G-CSF in pediatric patients who failed previous chemomobilization with G-CSF alone and possible complications of the treatment

Peripheral blood stem cell (PBSC) mobilization, which uses plerixafor (AMD 3100), a newly developed specific inhibitor of the CXCR4 receptor, in combination with granulocyte-colony stimulating factor(G-CSF), has been shown to enhance the stem cell mobilization in adult patients, but pediatric data are scarce. We documented our experience with this drug in 6 Korean pediatric patients who had failed in chemomobilization, using G-CSF, alone. All patients were mobilized CD34+ cells (median, 11.08 × 106/kg: range, 6.34-28.97 × 106/kg) successfully within 2 to 3 cycles of apheresis, without complications. A total of 7 autologous transplantations were performed, including 1 tandem transplantation. However, 2 patients with brain tumors showed severe pulmonary complications, including spontaneous pneumomediastinum. This is the first study of PBSC mobilization with plerixafor in Asian pediatric patients. Furthermore our study suggests that mobilization with plerixafor may be effective in Korean pediatric patients, who have previously been heavily treated and have failed PBSC mobilization with classical chemomobilization, using G-CSF. However, further studies are needed to examine the possible complications of autologous transplantation, using a mobilized plerixafor product in children.

Successful Mobilization with the Combination of Plerixafor and G-CSF in Korean Pediatric Patients Who Failed in Previous Chemomobilization with G-CSF Alone

Abstract 4397 Introduction:The classical peripheral blood stem cell mobilization (PBSCM) relies on granulocyte colony-stimulating factor (G-CSF) either as a single agent or in conjunction with chemotherapeutic agents (chemomobilization). This method however, sometimes fails in patients who have previously been heavily treated with chemotherapy or radiotherapy. PBSCM with plerixafor (AMD3100), a newly developed specific inhibitor of the CXCR4 receptor, in combination with G-CSF has been shown to enhance stem cell mobilization in adult patients, but pediatric data is scarce. We document our experiences with this drug in five pediatric patients. Patients & Methods:Five patients (three males, two females) with a median age of 9.6 years (range 6–11 years) who have failed in chemomobilization with G-CSF alone, received plerixafor. The diagnosis of patients was medulloblastoma in 2, osteosarcoma in 2, and neuroblastoma in 1. All the patients had previously been heavily treated with chemotherapy (median 15.4 months) and two of them with medulloblastoma underwent craniospinal irradiation. Patients received G-CSF (10mcg/kg) for 4 days at 10 AM before the first plerixafor (240ug/kg) administration, which was given subcutaneously 10 hours before apheresis. Apheresis was performed thereafter on the fifth day of G-CSF administration. Patients received G-CSF at 8AM and apheresis was started at 10AM. Each apheresis was performed with plerixafor and G-CSF in the same manner. Results:All the patients mobilized targeted numbers of CD34+ cells (median 12.86×10^6/kg, range 6.34–28.97×10^6/kg) successfully with two to three cycles of apheresis, without complications (Per each apheresis: median 3.8×10^6/kg, range 1.55–14.49×10^6/kg). A total of four autologous transplantations were performed in 3 patients including one tandem transplantation in a neuroblastoma patient. Neutrophil and platelet were successfully engrafted in four transplantations within a median of 9.7 days (range 9–10 days) and 68.3 days (range 15–197 days), respectively. Conclusion:Our study suggests that mobilization with plerixafor is safe and effective in Korean pediatric patients who have previously been heavily treated and have failed PBSC mobilization with classical chemomobilization with G-CSF. This is the first results of PBSCM with plerixafor in Asian pediatric patients. Disclosures:No relevant conflicts of interest to declare.

Blood CD34 Levels as a Predictor of Successful Peripheral Blood Stem Cell Mobilization In Consecutive Autologous Stem Cell Apheresis Patients From a Single Transplant Center

AbstractAbstract 4440 Background:The optimal strategy to mobilize hematopoietic stem cells into peripheral blood for collection has not been defined, and some patients do not successfully mobilize. Failure to harvest the desired number of CD34+ cells results in emotional disappointment for the patient and ineffective utilization of resources. In this study we analyzed various factors influencing CD34+ yields during stem cell collection in patients being considered for autologous transplantation whose peripheral blood CD34+ analysis triggered stem cell collection (usually >10/μ L), and we determined thresholds for successful collection in a single apheresis session. Method:Retrospective chart review of 244 consecutive patients who underwent stem cell collection at the University of Rochester between 2005 and 2008 was conducted. Cells were collected via Cobe semi-automated protocols. For each of the patients, diagnosis, age, gender, type of infusion, marrow status, number of prior chemotherapy treatments, mobilization regimen, CD34+ count/μ l on first day, CD34+/kg after first apheresis, total time of apheresis and volume processed (liters) were recorded. The various mobilization regimens utilized were 1)GCSF, 2)CHEMO (salvage therapy with DHAP, ESHAP, RICE) with GCSF, 3)cyclophosphamide with GCSF, 4)AMD3100 (Plerixafor) with GCSF, and 5) GCSF with GMCSF. The marrow status was defined as no involvement, mild involvement (10-20%), and moderate involvement (>20%). Another factor considered was the number of prior chemotherapy regimens, and the total number of apheresis cycles required to reach targeted yields was recorded. All statistical analyses were conducted using SAS 9.2. All tests were two-sided with p-values ≤ 0.05 considered significant. Result:Analysis revealed a positive linear relationship between the log of initial CD34+ counts and the log transformed number of CD34+ cells/kg on the first day of apheresis (R2= 0.57, p < 0.001). Multivariate analysis suggested that both CD34+ count per μ L blood prior to first apheresis (p < 0.001) and time on the machine (p = 0.08) were positively associated with CD34+ end yield after adjusting for age and gender. A similar analysis on all the mobilization regimens revealed statistical significance for a higher initial CD34 cell count/μ l predicting a higher apheresis yield (p < 0.001). Also, for each of the major diagnoses (AL, HL, MM. NHL), there was a positive relationship between peripheral CD34+ cells/μ l prior to apheresis and CD34+ cells/kg after first apheresis yield (p < 0.001) Another objective of this study was to see if there is a threshold number of CD34+ cells/μ l blood that would predict for lymphoma patients (combined HL, NHL) that at least 4 × 106 CD34+ cells/kg would be reached on the first day of apheresis, and a similar threshold for the multiple myeloma patients (MM) to reach 6 × 106 CD34+ cells/kg on first day. Receiver operating characteristics (ROC) curves were used to determine an optimal initial CD34+ count cutoff and the odds ratio of achieving such a threshold between the two groups was assessed using logistic regressions. Based on the cutoff of 48.3 cells/μ L, lymphoma patients were classified into two groups depending on their initial CD34+ count greater or less than this cutoff. The odds of reaching at least 4 × 106 CD34+ cells/kg on the first day of apheresis when the initial CD34+ count was greater than 48.3 cells/μ L were 24.4 times than those with the initial CD34+ count less than the cutoff (p<0.001). Similarly, for multiple myeloma patients, to reach a threshold of 6×106 CD34+ cells/kg on the first day of apheresis, a cutoff of 90.5 cells/μ L was established. The odds of reaching at least 6×106 CD34+ cells/kg on the first day of apheresis with initial CD34+ count greater than 90.5 cells/μ L were 19.3 times than those with initial CD34+ count less than the cutoff (p<0.001) Conclusion:This study confirmed that the initial peripheral CD34+ count was a good predictor of the CD34+ cells/kg yield on the first day of apheresis, irrespective of disease type or mobilization regimen utilized. A threshold of 48.3 CD34+ cells/μ L for lymphoma patients and 90.5 CD34+ cells/μ L for myeloma patients was established to reach goals of least 4 × 106 CD34+ cells/kg and 6 × 106 CD34+ cells/kg respectively with a single apheresis. These thresholds or others calculated similarly for other collection goals could potentially aid in coordination of apheresis resource utilization. Disclosures:No relevant conflicts of interest to declare.

Stem cell collection in patients with multiple myeloma: impact of induction therapy and mobilization regimen

Lenalidomide is an active treatment for multiple myeloma (MM) and is increasingly used as part of the initial treatment of this disease. Recent reports have suggested decreases in the number of CD34+ cells collected and increases in the failure rate among patients whose initial therapy contained lenalidomide when mobilized with G-CSF alone. A retrospective data analysis of 364 patients with MM who underwent stem cell mobilization and attempted harvest at the Hospital of the University of Pennsylvania between January 2002 and December 2007 was performed. Forty-three of the patients received lenalidomide in their induction regimen, and were mobilized with either CY and G-CSF or G-CSF alone. The number of apheresis cycles and the failure rate were lower, whereas the mean number of collected stem cells was higher in patients who were mobilized with CY and G-CSF in comparison with G-CSF alone. This suggests that lenalidomide does not prevent the harvest of adequate numbers of CD34 cells for autologous stem cell transplant, but mobilization with G-CSF and CY may be required to obtain adequate numbers of stem cells. Finally, in our study, the number of lenalidomide cycles did not correlate with stem cell yield.

Silane coupling agent chemical burns: A risk for medical personnel too

Most of our knowledge of the effects of aging on the hematopoietic system comes from studies in animal models. In this study, to explore potential effects of aging on human hematopoietic stem and progenitor cells (HSPCs), we evaluated CD34+ cells derived from young (<35 years) and old (>60 years) adult bone marrow with respect to phenotype and in vitro function. We observed an increased frequency of phenotypically defined stem and progenitor cells with age, but no distinct differences with respect to in vitro functional capacity. Given that regeneration of peripheral blood counts can serve as a functional readout of HSPCs, we compared various peripheral blood parameters between younger patients (≤50 years; n = 64) and older patients (≥60 years; n = 55) after autologous stem cell transplantation. Patient age did not affect the number of apheresis cycles or the amount of CD34+ cells harvested. Parameters for short-term regeneration did not differ significantly between the younger and older patients; however, complete recovery of all 3 blood lineages at 1 year after transplantation was strongly affected by advanced age, occurring in only 29% of the older patients, compared with 56% of the younger patients (P = .009). Collectively, these data suggest that aging has only limited effects on CD34+ HSPCs under steady-state conditions, but can be important under consitions of chemotoxic and replicative stress.

No Evidence for Increased Transplant Related Complications in Ph+ Chronic Myelogenous Leukemia and Acute Lymphoblastic Leukemia with Prior Treatment with Dasatinib.

Stem cell transplantation (SCT) is frequently used as salvage or curative therapy in patients (pts) with advanced chronic myelogenous leukemia (CML) or Ph+ acute lymphoblastic leukemia(ALL) who were previously treated with Imatinib. While one study showed higher incidence of GVHD, VOD and TRM, most studies have demonstrated that Imatinib therapy prior to SCT does not adversely affect transplantation outcome. Dasatinib is a novel dual SRC/ABL kinase inhibitor currently being used in pts with Imatinib-resistant advanced CML or relapsed/efractory Ph+ ALL. Most of these pts will eventually undergo SCT, raising the question of whether Dasatinib therapy may adversely affect transplantation outcome. We report eight pts: CML -6 (CP1-4, low sokal score -3, high sokal score -1, CP2-1, AP-1) and Ph+ ALL -2 who received Dasatinib prior to alloSCT (n=7) or autoSCT (n=1). Donors were matched siblings -4, matched unrelated -2 or mismatch related donor (haploSCT) -1. Five were male and 3 female with a median age of 46.5 (16–56) years. First line therapies included Hydroxyurea or Interferon followed by Imatinib for the CP CML pts and chemotherapy followed by Imatinib for the advanced CML and Ph+ ALL pts. All pts subsequently received Dasatinib 70mg × 2/day due to resistance to Imatinib, resulting in complete hematological response in all, as well as complete (n=5) or partial cytogenetic response (CyR) (n=2) prior to SCT. One pt did not achieve CyR prior to SCT. The pts were conditioned with either a myeloablative protocol (n=5) or a reduced intensity protocol (n=3). GVHD prophylaxis consisted of CSA and MTX (n=6) or complete T-cell depletion (n=1). Pts received a mobilized peripheral blood stem cell graft with 11.4–19.8 × 106 CD34+ cells/kg. The pt who underwent autoSCT was successfully mobilized (2 apheresis cycles yielding 5.7 × 106 CD34+/kg). Dasatinib was stopped 6 days before mobilization. All pts successfully engrafted reaching ANC > 0.5×109/L on day +14 (11–21) and PLT >20×109/L on day +12.5 (11–17). Chimerism was 99.4 – 100%. Transplant related toxicities were minimal. Only one pt developed severe mucositis. No pt developed hyperbilirubinemia or VOD. There was no increased risk of infections. Acute GVHD (Gr II) was observed in only 1 pt, while 2 developed extensive chronic GVHD (1 after stopping immunosuppression). With a median follow-up of 8.5 (2–13) months, six pts are alive, 5 in CR, while 2 died of disease progression. We may conclude that in pts undergoing SCT following Dasatinib there is no evidence that Dasatinib adversely affect post SCT outcome, as no increased transplant related organ toxicities, non-engraftment, GVHD or infections were observed. Larger studies are obviously indicated to confirm our preliminary results.

Predictive value of the original content of CD34+ cells for enrichment of hematopoietic progenitor cells from bone marrow harvests by the apheresis procedure

We retrospectively investigated the feasibility of the apheresis procedure for red blood cell (RBC) reduction with a closed-bag system. We also sought to determine the optimal processing volume for the maximal recovery of hematopoietic progenitor cells (HPC). Twelve bone marrow (BM) harvests were processed for major ABO-incompatible allogeneic transplantation and one BM harvest was processed for autologous transplantation. The processing was performed through seven apheresis cycles with a two-bag system using COBE Spectra Version 6.1. The mean recovery rates were compared in the products after four cycles and seven cycles of BM processing. Mean cell recovery rates were 79.2% (67.6-97.5%) and 87.3% (68.9-111.9%) for the mononuclear cells (MNC) and 84.5% (69.4-109.5%) and 92.0% (79.0-107.7%) for the CD34(+) cells after four and seven cycles, respectively. A mean of 96.3% (93.0-98.1%) of the RBCs were finally removed. The yield of CD34(+) cells after seven cycles of processing (median: 10.35 x 10(7) cells) was 7.9% greater than that after four cycles of processing (median: 9.65 x 10(7) cells), exhibiting a less-than-significant enhancement in yield. The CD34(+) cell contents recovered in the concentrates up to four cycles (r = 0.989) and up to seven cycles (r = 0.993) were strongly correlated with the original content of the CD34(+) cells. Engraftment was obtained in all patients except one patient infused with purified CD34(+) cells. This latter result confirmed the hematopoietic potential of the cell populations recovered. Granulocyte recovery (defined as an absolute neutrophil cell count > or = 500/microL for a period of three consecutive days) ranged from 8 to 25 days (median: 16 days) post-transplantation. No hemolytic reaction was observed in any of the patients. Our results confirmed the efficacy of BM processing cycles with the COBE Spectra device. However, we could not conclude that the large-volume apheresis for BM processing significantly enhanced the yields of HPC. The final recovery of CD34(+) cells after processing could be predicted from the CD34(+) cell content of the original collected marrow.

Cytapheresis Therapy for Ulcerative Colitis in Three Pediatric Patients

Cytapheresis Therapy for Ulcerative Colitis in Three Pediatric Patients

Monitoring of peripheral blood CD34+ cell counts on the first day of apheresis is highly predictive for efficient CD34+ cell yield.

The purpose of this study was to evaluate the correlation of preleukapheresis circulating CD 34+ cells/micro L, white blood cells (WBC), and platelet counts on the first day of apheresis with the yield of collected CD 34+ cell counts in 40 patients with hematological malignancies (n = 29) and solid tumors (n = 11). The median numbers of apheresis cycles, numbers of CD 34+ cells, peripheral blood (PB) mononuclear cells, and total nucleated cells collected were 2 (range, 1-4), 5.5 x 106/kg (range, 0.05-33.78), 2.59 x 108/kg (range, 0.04-20.68), and 7.36 x 108/kg (range, 0.15-28.08), respectively. There was a strong correlation between the number of preleukapheresis circulating CD 34+ cells/micro L and the yield of collected CD 34+ cells per kilogram (r = 0.962, p < 0.001). The threshold levels of PB C 34+ cell/micro L to obtain > or =1 x 106/kg and > or =2.5 x 106/kg CD 34+ cell in one collection were 12/micro L and 34/ micro L, respectively. Fifteen of 17 (88%) patients who had > or =34 CD 34+ cells/ micro L in the PB before collection reached the level of > or =2.5 x 106/kg in a single apheresis. Despite a low r value, WBC and platelet counts on the first day of apheresis also correlated with the yield of collected daily CD 34+ cells per kilogram (r = 0.482, p < 0.01 and r = 0.496 p < 0.01, respectively). These data suggest that preleukapheresis circulating CD 34+ cells/ micro L correlated significantly better with the yield of collected CD 34+ cells than WBC and platelet counts on the first day of apheresis. Using a value of 34/micro L preleukapheresis circulating CD 34+ cells as a guide for the timing of peripheral blood stem cells collections can be time saving and cost-effective.