Hematopoietic Stem Cell Collection Research Articles

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.

Evaluation of blood cell count using an automatic hematology analyzer to optimize collection of peripheral blood progenitor cells by leukapheresis

BackgroundAutologous stem cell transplantation is a treatment modality for several diseases. Prediction of successful mobilization may be useful to optimize hematopoietic stem cell collection. Study design and methodsThis was a retrospective study with data from transplantation candidates between September 2015 and December 2021 being analyzed. The medical record of each patient was reviewed to mine mobilization information. The laboratory data analyzed were CD34+ cell enumeration and pre-collection peripheral blood cell count. The primary outcome, good mobilization, was defined as a CD34+ cell count ≥20/μL. ResultsThis study included 807 patients. Increased patient weight, low mean corpuscular volume, high nucleated red blood cells, peripheral blood mononuclear cell and immature granulocyte counts were significantly associated with good mobilization. In addition, patients diagnosed with multiple myeloma were two times more likely to be good mobilizers than patients with lymphoma. The model was applied to a validation set to identify patients who underwent apheresis (CD34+ cell count ≥10 µL), resulting in a sensitivity of 69 %, a specificity of 95 %, positive predictive value of 98 %, and a negative predictive value of 50 %. ConclusionSuccess in mobilization was greater in patients who underwent the first mobilization cycle and who had a diagnosis of multiple myeloma. Furthermore, higher body weight, and nucleated red blood cells, immature granulocytes and mononuclear cell counts, as well as low mean corpuscular volumes, were associated with successful mobilization.

Effect of prior lenalidomide or daratumumab exposure on hematopoietic stem cell collection and reconstitution in multiple myeloma.

The roles of Lenalidomide (Len) and Daratumumab (Dara) in multiple myeloma treatment are well-established, yet their influences on hematopoietic stem cell harvesting and reconstitution remain disputed. We conducted a systematic database review to identify cohort studies or RCTs evaluating the effect of the use of Len or Dara on hematopoietic stem cell collection and peripheral blood count recovery in multiple myeloma patients. Effects on hematopoietic collection or reconstitution were estimated by comparing standardized mean differences (SMD) and mean differences (MD), or median differences. Eighteen relevant studies were identified, summarizing mobilization results. For Len, data from 13 studies were summarized, including total CD34+ cell yield, collection failure rate, and time to neutrophil and platelet engraftment. Results indicated that Len exposure led to decreased stem cell collection [SMD=-0.23, 95% CI (-0.34, -0.12)]. However, collection failure (<2×106) could be mitigated by plerixafor [OR=2.14, 95% CI (0.96, 4.77)]. For Dara, two RCTs and three cohort studies were included, showing that Dara exposure resulted in a reduction in total stem cells even with optimized plerixafor mobilization [SMD=-0.75, 95% CI (-1.26, -0.23)], and delayed platelet engraftment recovery [MD=1.20, 95% CI (0.73, 1.66)]. Our meta-analysis offers a comprehensive view of Len and Dara's impacts on hematopoietic stem cell collection and reconstitution in multiple myeloma. Len usage could lead to reduced stem cell collection, counteracted by plerixafor mobilization. Dara usage could result in diminished stem cell collection and delayed platelet engraftment.

Motixafortide Enables Consistent, Robust Hematopoietic Stem Cell Collection (HSC) across Populations with Increased Impaired HSC Mobilization: A Sub-Group Analysis of the Genesis Study

Motixafortide Enables Consistent, Robust Hematopoietic Stem Cell Collection (HSC) across Populations with Increased Impaired HSC Mobilization: A Sub-Group Analysis of the Genesis Study

Effect of voxelotor on murine bone marrow and peripheral blood with hematopoietic progenitor cell mobilization for gene therapy of sickle cell disease

In preparation for hematopoietic stem cell mobilization and collection, current ex vivo gene therapy protocols for sickle cell disease require patients to undergo several months of chronic red cell transfusion. For health care equity, alternatives to red cell transfusion should be available. We examined whether treatment with GBT1118, the murine analog of voxelotor, could be a safe and feasible alternative to red cell transfusion. We found that 3 weeks of treatment with GBT1118 increased the percentage of bone marrow hematopoietic stem cells and upon plerixafor mobilization, the percentage of peripheral blood hematopoietic stem cells. Our data suggest that voxelotor should be further explored for its potential safety and utility as preparation for hematopoietic stem cell mobilization and collection.

The Italian registry of therapeutic apheresis in SISTRA: Year of activity 2022

Therapeutic apheresis refers to a group of extracorporeal blood processing procedures used in the treatment of a variety of systemic diseases. These complex procedures are burdened by adverse reactions related to both procedures and underlying medical conditions.Given the importance of centralizing the collection and the analysis of information on therapeutic apheresis, the Italian National Blood Center (NBC), at the request of the Italian Scientific Society of Hemapheresis and Cell Manipulation (SIdEM), implemented the Italian Registry of Therapeutic Apheresis (IRTA) including it in the Information System of Transfusion Services (SISTRA), coordinated by the NBC.In 2022, a total of 34,702 therapeutic apheresis procedures was carried out in 8,781 patients, including paediatric patients, with an average of 3.9 procedures per patient. The 2022 IRTA data indicate that the patient with hematological and/or neurological disorders mainly turns to the apheresis centers. These results confirm the IRTA data from years 2020 and 2021. In the hematological field, the apheresis centers supply hematopoietic stem cells collection for autologous transplantation as well as mononuclear cell collection for extracorporeal photopheresis. With regard to the neurological field, myasthenia, chronic inflammatory demyelinating polyneuropathy and Guillain-Barré syndrome along with other neurological pathologies related to immune disorders are the most treated.In conclusion, this manuscript presents 2022 activity data of IRTA providing institutions and scientific societies with a wide range of information including type and number of therapeutic procedures, adverse events and patients’ outcome.

Comparison of Various Stem Cell Mobilization Regimens for Multiple Myeloma - a 15-Year Retrospective Institutional Analysis from India

Introduction For multiple myeloma (MM), Cyclophosphamide (Cy) based chemo-mobilization offers advantage in term of higher stem cell yield and can overcome adverse impact of prior lenalidomide therapy on stem cell harvest. However, considering need for hospital stay and risk of febrile neutropenia, steady state mobilization with G-CSF and pre-emptive plerixafor (PEF) is becoming increasingly popular. Until few years back, cost of PEF was prohibitive thereby limiting its use and prompting a search for alternative cheaper drugs. Mouse models have shown that Proteasome Inhibitors aid in hematopoietic stem-cell (HSC) mobilization by down-regulating very-late antigen-4 (VLA-4) on bone marrow stromal cells which interacts with vascular cell adhesion molecule (VCAM-1) on HSC. We previously reported that bortezomib (Bort) in combination with Cy-G-CSF showed a trend towards higher CD34 yield and reduced need for apheresis sessions, without additional toxicity. There is limited data comparing mobilization regimens, especially from low-middle income countries where HSC collection may not be done after 4-6 cycles of first-line therapy. We hereby report our 15-year experience of various mobilization regimens for MM. Methods All patients with MM who underwent HSC mobilization from September 2007 - December 2022 were included in this analysis. Various mobilization regimens [Group 1 - G-CSF + Bort (August 2018 - December 2022); Group 2 - G-CSF + plerixafor (August 2018 - December 2022); Group 3 - Bort-Cy-GCSF (April 2016 - July 2018); Group 4 - Cy + G-CSF (September 2007 - March 2016)] were used as per respective time-periods (Table 1). Our aim was to collect CD34 cell dose of 5million/kg to suffice for 2 transplants. G-CSF (5 mcg/kg subcutaneously BD) was given on days 1-5 (Groups 1 and 2). Bort (1.3mg/m 2 iv / sc) (Group 1) or PEF (Group 2) were given on day 4 twelve hours prior to planned apheresis on day 5. Apheresis was done on day 5, and additionally on day 6, if first harvest was inadequate for 2 transplants. In group 3, Bort (1.3mg/m 2 iv) was given on days-1,4,8,11, with Cy (1gm/m 2 iv) on days 8 and 9, followed by G-CSF from day 11 onwards. Cy (1gm/m 2 iv) was given on day 1 and 2 (Group 4), followed by G-CSF from day 4 onwards. Stem cell harvest was done in groups 3 and 4 once peripheral blood CD34 (PB CD34) was &amp;gt;20/µL. In groups 3 and 4, if PB CD34 was &amp;lt;20/µL for 2 subsequent days, PEF was used according to physician's discretion, if available. Similarly in Group 1, if PB CD34 was between 10-20/µl on day 4, PEF was used according to physician's discretion. PEF was used in any group after the first harvest if the cell dose was deemed inadequate, at physician's discretion. Primary objective was to determine proportion of patients with CD34 + dose ≥5x10 6/kg in first apheresis in various groups. Secondary objectives were to determine total median CD34 + dose (x10 6/kg) collected, median CD34 + (x10 6/kg) in first apheresis, and frequency of mobilization failure. Mobilization failure was defined as total collected CD34 + dose of &amp;lt;2x10 6/kg or abandoned harvest attempt anticipating a poor collection.Analysis was done as per planned regimen (intention to treat analysis). Results Total 205 patients were analyzed. Median age was 48 years (27-65 years) and 143 (70%) were males (Table 1). Median day of first collection in groups 3 and 4 was day10 from the first dose of cyclophosphamide. Percentage of patients who collected ≥5x10 6 CD34 + cells/kg in first apheresis were 26%, 53%, 69% and 63%, respectively in Groups 1-4 (p=0.0001) (Table 1). CD34+ cell-dose in first apheresis and total dose collected are shown in Table 1. In comparison to groups 1 and 2, both chemo-mobilization groups (group 3 and 4) had a significantly higher total cell dose (Figure 1). In comparison to group 1, both Cy chemo-mobilization groups had a significantly higher cell dose in first harvest, but there was no significant difference between group 2 and group 4 (p=0.23) (Figure 1). PEF was required additionally in 47%, 22%, and 7% of patients in groups 1, 3 and 4 respectively (P&amp;lt;0.00001). Amongst transplanted patients, there was no difference in neutrophil or platelet engraftment and the frequency of engraftment syndrome in various groups. Conclusion Cy-based chemo-mobilization regimens have advantage of higher total stem cell yield, while they are equivalent to G-CSF + Plerixafor for harvest in single apheresis. Addition of Bortezomib to Cyclophosphamide may help to increase stem cell yield.

Improvement in Iron Burden in Patients with Transfusion-Dependent β-Thalassemia (TDT) Treated with Betibeglogene Autotemcel (Beti-cel) Gene Therapy: Up to 9 Years of Follow-up

Introduction: Beti-cel is an approved, one-time gene therapy treatment for adult and pediatric patients with TDT. Beti-cel consists of autologous hematopoietic stem and progenitor cells transduced with the BB305 lentiviral vector encoding a modified β-globin gene (β A-T87Q), which produces functional hemoglobin (Hb) and addresses the underlying genetic cause of TDT. While transfusion independence (TI) remains a critical component for assessing patient response to gene therapy, other measures, including markers of iron overload, are important for evaluating the impact of therapy and management of disease burden over time. Previously, we demonstrated that iron markers stabilized in patients who achieved TI and stopped chelation therapy. Here, we report iron management outcomes in patients who completed either a phase 1/2 or phase 3 beti-cel parent study and subsequently enrolled in the long-term follow-up study. Methods: Patients with TDT who completed a parent beti-cel study (phase 1/2 studies: HGB-204 [NCT01745120]; HGB-205 [NCT02151526]; phase 3 studies: HGB-207 [NCT02906202]; HGB-212 [NCT03207009]) could enroll in a long-term study (LTF-303 [NCT02633943]) for up to an additional 13 years of follow-up. In these studies, TI was defined as a weighted average Hb ≥9 g/dL without packed red blood cell transfusions for ≥12 months. Iron removal therapy was at the discretion of the treating physician. Liver and cardiac magnetic resonance imaging evaluated liver iron concentration (LIC) and cardiac T2*; serum ferritin and transferrin receptor (TfR) were assessed at regular intervals according to protocol. Results:As of January 30, 2023, 63 patients received beti-cel; median (range) follow-up was 60.1 (23.8-109.5) months. In phase 3 studies, 37/41 (90%) patients achieved TI and maintained TI through the last follow-up, which was 5+ years for 10 patients ( Figure 1). In phase 1/2 studies, 15/22 (68%) patients achieved TI; 14 of these patients maintained TI through the last follow-up, which was up to 9 years. One patient no longer meets protocol-defined TI as a result of Hb level &amp;lt;9g/dL at year 6 due to acute health events unrelated to β-thalassemia, which were not attributed to loss of beti-cel treatment effect. In total, 51 patients across phase 1/2 and 3 studies achieved and maintained TI through last follow-up with 35/51 (69%) patients off chelation. Thirty of 51 patients had an LIC measurement at month 48. Of these 30 patients, 21 had an LIC &amp;lt;5 mg/g at month 48 post infusion. Among these 21 patients, 5 never restarted chelation after infusion (2 received phlebotomy only), 11 restarted chelation and then were able to discontinue after iron stores normalized (1 also received phlebotomy), and 5 continue to receive chelation (none had phlebotomy). The other 9 patients who had an LIC measurement at month 48 had an iron burden ≥5 mg/g. All 9 of these patients restarted chelation; 4 were able to discontinue (2 had phlebotomy) and 5 continue to receive chelation (1 had phlebotomy). Analysis of iron marker stabilization after discontinuation of chelation will be presented. The median (range) change from baseline in LIC levels at month 48 was -3.9 (-22.3 to 10.5) mg Fe/g dry weight; the median (range) change from baseline in serum ferritin was -2119.0 (-7211 to 3889) pmoL/L. Reductions from baseline in serum TfR were observed at month 36; cardiac T2* remained stable at month 48 ( Table 1). Safety of beti-cel treatment largely reflected the known side effects of hematopoietic stem cell collection and the busulfan conditioning regimen. Conclusion: In this analysis with up to 9 years of follow up, patients treated with beti-cel who achieved TI also demonstrated sustained improvements in iron burden, and the majority of patients were able to stop chelation. Collectively, these results demonstrate the long-term durability and stability of response after beti-cel gene therapy in patients with TDT.

A prospective, multicenter study on hematopoietic stemcell mobilization with cyclophosphamide plus granulocyte colony-stimulating factor and 'on-demand' plerixafor in multiple myeloma patients treated with novel agents.

High-dose melphalan plus autologous stem cell transplantation (ASCT) is a standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM), and adequate hematopoietic stem cell (HSC) collection is crucial to ensure hematologic recovery after ASCT. In this prospective, observational study we evaluated HSC mobilization with granulocyte colony-stimulating factor (G-CSF), cyclophosphamide, and 'on-demand' plerixafor (in patients with <20×106 CD34+ cells/L after at least 4 days of G-CSF or failing to collect ≥1×106 CD34+ cells/kg after the first apheresis) in NDMM patients treated with novel agent-based induction therapy. The primary endpoint was the rate of poor mobilizers (patients collecting <2×106 CD34+ cells/kg or requiring plerixafor rescue to reach an adequate HSC harvest). Secondary endpoints included the rate of patients collecting ≥2×106 CD34+ cells/kg after plerixafor administration and the identification of factors predicting mobilization failure or plerixafor need. Overall, 301 patients (median age 60 years) were enrolled. Two hundred and eighty-seven of 301 (95%) and 274 of 301 (93%) patients collected ≥2×106 and ≥4×106 CD34+ cells/kg, respectively, with a median of 9.9×106 CD34+ cells/kg collected. Poor mobilizers were 48 of 301 (16%): 34 of 301 (11%) required plerixafor rescue, and 14 of 301 (5%) failed HSC collection regardless of plerixafor. Thirty-four of 38 (90%) patients receiving plerixafor collected ≥2×106 CD34+ cells/kg. Bone marrow plasmacytosis at diagnosis >60% (odds ratio [OR]=4.14), lenalidomide use (OR=4.45), and grade 3-4 hematologic toxicities during induction (OR=3.53) were independently associated with a higher risk of mobilization failure or plerixafor need. Cyclophosphamide plus G-CSF and 'on-demand' plerixafor is an effective strategy in NDMM patients treated with novel agents, resulting in a high rate of HSC collection and high HSC yield (clinicaltrials gov. identifier: NCT03406091).

Comparison of different plerixafor-based strategies for adequate hematopoietic stem cell collection in poor mobilizers

Objectives: The main objective of the present study was to evaluate whether the use of plerixafor in combination with granulocyte colony-stimulating factor (G-CSF) or subsequent use of isolated G-CSF and then plerixafor following disease-specific chemotherapy, and whether it would allow for adequate peripheral stem cell collection in patients. Methods: The retrospective study evaluated 54 patients with previous mobilization failure who were administered plerixafor in 2 centers. In patients without any side effects, CD 34+ cell counts, the percentage of patients who were found eligible for autologous transplantation, the engraftment kinetics of the patients who underwent transplantation, and their overall survival results were compared between the two groups where G-CSF was used with plerixafor, or where plerixafor was used after isolated G-CSF following chemotherapy. Results: The median age of the patients was 49 years (range: 17-70), and 64.8% (n = 35) were males. It was identified that 31 (57.4%) patients underwent mobilization treatment with isolated G-CSF and plerixafor, and 23 (42.6%) patients underwent mobilization treatment with chemotherapy plus G-CSF and plerixafor. In all patients, mean hemoglobin level (11.3 ± 1.5 g/dL vs. 9.3 ± 1.3 g/dL; p &amp;lt; 0.001) and median platelet level (129.2 ×103/µL vs. 58.4 ×103/µL) were found to be higher, while febrile neutropenia rate (3.3% vs. 60.9%), the percentage of replacement patients (6.7% vs. 65.2%), and median days of G-CSF (6 vs. 9) were found to be lower on the day of plerixafor administration in the isolated G-CSF and plerixafor group compared to the chemotherapy and G-CSF and plerixafor group. Conclusions: In conclusion, our study demonstrated that administration of plerixafor is generally safe and well-tolerated. Regardless of the underlying disease, it offers an effective alternative for patients with previous failed mobilization attempts using conventional regimens, and allows stem cell collection with fewer apheresis sessions.

Impact of Daratumumab on Hematopoietic Stem Cell Mobilization with G-CSF and on-Demand Plerixafor in Newly-Diagnosed Multiple Myeloma Patients

Introduction Autologous stem cell transplantation (ASCT) is a standard of care for transplant eligible (TE) patients with newly diagnosed (ND) multiple myeloma (MM); therefore, an adequate hematopoietic stem cell (HSC) collection is crucial to allow patients to proceed to ASCT and ensure optimal hematologic recovery. A more frequent use of plerixafor (PLX) and lower HSC yields have been reported in patients treated with daratumumab, a backbone of induction therapy for NDMM patients. Chemotherapy-free mobilization with G-CSF and on-demand PLX is an effective mobilization strategy lacking chemotherapy-related toxicities. Here we present the results of a multicenter, retroprospective and prospective, observational study, aiming to compare the impact of daratumumab on HSC mobilization with G-CSF + on-demand PLX in patients with NDMM treated with bortezomib-thalidomide-dexamethasone (VTd) or VTd plus daratumumab (D-VTd). Methods NDMM patients undergoing a first HSC mobilization attempt with G-CSF (10 mcg/kg/day) were enrolled and observed up to 30 days after ASCT. According to its label, on-demand PLX was administered in patients with &amp;lt;20 CD34 + cells/µL after ≥ 4 days of G-CSF or in case &amp;lt;1×10 6 CD34 + cells/kg were collected on the first day of apheresis. The primary endpoint of the study was the rate of poor mobilizing patients (≤2x10 6 CD34 + cells/Kg collected or need for PLX to reach an adequate HSC harvest). Key secondary endpoints included: the rate of suboptimal (2 to 4 CD34 + cells/kg) and optimal (≥4 CD34 + cells/Kg) collection; the median number of apheresis required to obtain ≥2x10 6 CD34 + cells/Kg; the impact of daratumumab on HSC engraftment. Results A total of 190 NDMM patients (median age, 62 years) were enrolled in 2 Italian centres (IRCSS Istituto Clinico Humanitas and Città della Salute e della Scienza di Torino) and analyzed; of these, 70% (133/190) were treated with VTd and 30% (57/190) with D-VTd. The median number of induction cycles was 4 in both groups. Best response after the induction phase was at least very good partial response (VGPR) in 87/133 (65%) and 41/57 (72%) of patients treated with VTd or D-VTd, respectively (p=0.4). The median time from the end of induction to G-SCF administration was 24 days in the VTd group and 29 days in the D-VTd group (p=0.5). The rate of poor mobilizing patients was 31% (41/133) in the VTd group and 54% (31/57) in the D-VTd group (p=0.002), mainly due to a higher rate of PLX use in the D-VTd as compared to the VTd group (53% vs. 28%; p=0.001), while the rate of patients who failed HSC mobilization (≤2x10 6 CD34 + cells/kg collected) was similar in the two groups (2% vs. 3%; p=1). Despite a numerically higher median number of CD34 + cells collected in the VTd group (7.9) as compared to the D-VTd group (7.1; p=0.009), no difference in the rate of patients who collected 2-4 (5% vs. 5%; p=1) and ≥4 CD34 + cells/Kg (95% vs. 95%; p=1) was observed in the VTd and D-VTd groups, respectively. A higher median number of CD34 +/µL on the first day of count was observed in the VTd as compared to the D-VTd group (24.5 vs. 19, p=&amp;lt;0.001). Among patients who had &amp;lt;20 CD34 +/µL [32% (43/133) vs. 51% (29/57)] on the first day of count, a similar increase in the CD34 +/µL (48.5 vs. 55) was observed in the two groups after PLX administration. The median number of apheresis session needed to complete the harvestwas 1 fo the VTd group and 2 in the D-VTd group (p=0.1). Neutrophil and platelet recovery were achieved in 100% of patients with a median time to neutrophil recovery of 15 and 13 days in the VTd and D-VTd groups, respectively (p=&amp;lt;0.001) and a median time to platelet recovery of 16 and 14 days in the VTd and D-VTd groups, respectively (p=0.001). Conclusion G-CSF plus on-demand PLX for HSC mobilization demonstrated to be an effective strategy in NDMM patients treated with VTd with or without daratumumab, resulting in very low rates of mobilization failures irrespective of the use of daratumumab during induction. Despite a higher rate of patients requiring PLX for HSC collection and lower CD34 + yields, the incorporation of daratumumab as part of the induction treatment did not negatively impact the possibility to achieve an optimal HSC collection. Our results, along with the lack of chemotherapy-associated toxicity, support the use of a chemotherapy-free HSC mobilization with G-CSF and on-demand plerixafor also in patients receiving daratumumab upfront.

Predictive Modeling of Hematopoietic Stem Cell Mobilization and Collection Based on Peripheral Blood Marker

Background: Autologous stem cell transplantation (ASCT) is the major transplantation therapy for patients with lymphoma and MM, and the success of auto-HSCT depends on the mobilization efficiency of peripheral blood HSC. In clinical practice, CD34 + cell count in peripheral blood is often monitored to predict the collection effect and determine the collection time. However, prediction of poor mobilizers is still difficult . Methods: We retrospectively analyzed 108 patients with lymphoma and multiple myeloma(MM) at Chongqing University Cancer Hospital who underwent autologous hematopoietic stem cell (HSC) collection between January 2021 to August 2022. There are two groups: collection success group and collection failure group. Compared the differences of clinical characteristics and impact of peripheral blood related detection indexes before autologous HSC collection. Logistic regression analysis was used to establish a prediction model for the successful collection by multi-marker and further evaluated multi-marker prediction models. Results : There was no significant difference in sex, disease type, disease stage, age, disease status before mobilization, mobilization drugs and chemotherapy courses between the successful collection group and the failed collection group ( P&amp;gt; 0.05). The proportion of patients with mobilization days less than 5 days was higher in the successful collection group ( P&amp;lt; 0.05). The platelet count (PLT), mononuclear cell count (MNC) and absolute CD34 + cell count in the successful collection group were significantly higher than those in the failure group. The sensitivity, specificity and area under the curve (AUC) of combining three indexes were 80.9%, 95.9% and 0.944, respectively. Applied the Logistic regression models to the absolute count of PLT, MNC and CD34 + cells to construct the multi-marker prediction algorithms. The 3-marker model of PLT+MNC+CD34 + cells had the lowest AIC, BIC and high AUC. A prediction model was established based on the absolute count of PLT, MNC and CD34 + cells. Conclusion :Patients with less than 5 days of mobilization have a higher success rate of collection. PLT, MNC and CD34 + cell counts before collection can reflect HSC mobilization in patients with lymphoma and MM, and the combination of the three can improve the accuracy of prediction of collection effect.The predictive model based on the absolute number of PLT, MNC and CD34 + cells have good predictive value. Our study suggests that multi-markers are important diagnostic tools for predicting successful collection.

Efficacy and Tolerance of Isatuximab, Cyclophosphamide, Bortezomib, and Dexamethasone (Isa-CBD) Induction Chemotherapy in Newly Diagnosed, Transplant Eligible Multiple Myeloma: Report of the Phase 2 Multi-Centre, Open Label Canadian Myeloma Research Group (CMRG)-008 Prospective Clinical Trial

Background: The previous standard Canadian approach to autologous stem cell transplantation (ASCT) included CyBorD induction and single-agent lenalidomide maintenance until progression (Cote J, et al. ASH 2022: abstract 117). In an effort to improve outcomes, the current Canadian Myeloma Research Group (CMRG)–008 trial aimed to assess the efficacy and tolerance of a regimen of isatuximab-CyBorD (Isa-CyBorD) induction, stem cell mobilization/collection, high-dose melphalan with ASCT, followed by continuous maintenance with isatuximab and lenalidomide in newly diagnosed multiple myeloma (NDMM) patients eligible for transplant. We now report the first planned analysis of Isa-CyBorD induction and stem cell mobilization and collection. Methods: This is a multi-centre phase 2 prospective study conducted in 8 centres in which transplant-eligible NDMM (TE-NDMM) patients received isatuximab added to four cycles of standard induction CyBorD chemotherapy (cyclophosphamide 300 mg/m 2 PO, bortezomib 1.5 mg/m 2 SC, and dexamethasone 40 mg PO, all given on days 1, 8, 15 and 22 of a 28-day cycle along with isatuximab 10 mg/kg IV days 1, 8, 15 and 22 of cycle 1 and days 1 and 15 of cycles 2-4). Isatuximab premedication also included acetaminophen, H2-antagonist (ranitidine) or proton pump inhibitor and montelukast. No thromboprophylaxis required per protocol. After the completion of induction treatment, subjects achieving ≥ stable disease (SD) proceeded to mobilization and collection of hematopoietic stem cells (SCs) per local institutional standards. Eligible patients with successful SC collection then proceeded to high-dose melphalan 200 mg/m 2 followed by ASCT. Maintenance treatment commenced at 100 days (+/- 7 days) post-ASCT and continued until disease progression. Maintenance treatment consisted of 28-day cycles of isatuximab (10 mg/kg IV on days 1, 8, 15 and 22 of cycle 1; days 1 and 15 of cycles 2-3; then day 1 of each subsequent cycle) administered with lenalidomide (10 mg daily on days 1-21). Results: Between December 2022-January 2023, 71 patients with ECOG ≤ 2 were enrolled: 25 females, 46 males; median age 61 years (range: 31-73); 46.5%, 35.2% and 18.3% were ISS stages I, II and III, respectively. High-risk cytogenetics were documented in 20.6% of evaluable patients (13/63). All completed Isa-CyBorD induction therapy. The treatment was well-tolerated with rare grade 3 - 4 adverse events: neutropenia (8.2%), anemia (8.2%) and febrile neutropenia (4.1%). Common side-effects (All grades combined, ≥20%) included nausea (50%), constipation (28%), fatigue (28%), peripheral neuropathy (27% - all ≤ grade 2 with no dose holds for neuropathy), insomnia (24%), diarrhea (22%), infusion-related reaction (22%). Response assessment at the end of induction was available for 57 pts by the data cut-off date (June 1 st, 2023). All patients had clinical improvement with no primary progressive disease. Complete response (CR), very good partial response (VGPR) and partial response (PR) were documented in 7%, 52.6% and 33.3%, respectively. Four patients (7%) had &amp;lt;50% improvement of M-protein (SD). Three patients did not proceed to stem cell transplantation due to patient / physician choices. SC mobilization utilized cyclophosphamide in 10 (15.4%) and plerixafor in 12 (18.5%) patients; mobilization was successful in all 65 patients mobilized so far with 1-3 apheresis (median 2). The median number of CD34+ cells collected was 5.3 x10^6/kg (range: 2.25-7.28). Conclusion: Isa-CyBorD with weekly bortezomib is an effective induction therapy in patients with NDMM (93% ≥ PR with no progression and no mobilization failures). The treatment was well-tolerated with a side-effect profile comparable to our Canadian prior experience with CyBorD alone. All patients who proceeded to mobilization had successful collection of adequate number of SCs. Further follow-up is ongoing to assess long-term outcomes with this approach.

Impact of the Addition of Daratumumab to the Standard Bortezomib-Thalidomide-Dexamethasone Regimen on Hematopoietic Stem Cell Mobilization and Collection, Post-Transplant Engraftment and Infectious Complications: A Case-Control Multicentre Real-Life Analysis

Background The pivotal clinical trial CASSIOPEIA established the quadruplet Daratumumab-Bortezomib-Thalidomide-Dexamethasone (Dara-VTD) as superior with regards to the standard Bortezomib-Thalidomide-Dexamethasone (VTD) regimen as induction therapy in newly diagnosed transplant-eligible (NDTE) multiple myeloma (MM) patients. As a matter of facts, Dara-VTD is currently the approved induction scheme in NDTE MM patients in Italy. Previous reports showed that adding Daratumumab in induction therapy patients yielded to a higher number of poor mobilizers, with a lower median number of collected hematopoietic stem cells (HSC). However, these reports included different types of induction therapies, merging patients on and off clinical trials, and real-life data focusing exclusively on Dara-VTD is lacking. We report our experience on the impact of Dara-VTD on HSC mobilization and collection, with a retrospective comparison with a cohort of patients treated with VTD and we also provided data concerning post-transplant engraftment and infectious complications. Methods From January 2022 to June 2023, 109 NDTE MM patients from 5 Haematology Institutions received Dara-VTD treatment induction according to the approved doses and schedule. The control group consisted of 116 age-matched patients treated with VTD in the years 2015-2016. Mobilizing therapy consisted of cyclophosphamide 1-3 gr/sqm followed by granulocyte colony-stimulating factor (G-CSF) 10 mcg/kg starting the 5th day thereafter, with HSC harvest planned on the 11th day. Patients received only G-CSF 10 mcg/kg if they were older than 70 years or had renal impairment (i.e., eGFR &amp;lt; 50 ml/min). Poor mobilizer was defined as having less than 20 CD34+/µL in peripheral blood on the 11th day after cyclophosphamide and G-CSF or on the 4th day of G-CSF alone administration. In that case, plerixafor was added at the standard dose of 0.24 mg/kg. Results In the Dara-VTD group, 96/109 patients received cyclophosphamide and G-CSF; among them, 3 patients had failed a previous G-CSF mobilizing therapy, even with the addition of plerixafor. Thirteen patients received G-CSF only. In the VTD group, all patients had received cyclophosphamide and G-CSF. Pre-harvest median number of CD34+/mL in the Dara-VTD group was 26 (range 0.8-279) vs 76 (range 20-294) in the VTD group and the incidence of poor mobilizing patients was 41.7% vs 5.9%, respectively (OR 0.3, 95% CI 0.16-0.54, P &amp;lt; 0.0001). Baseline disease characteristic did not have an impact on poor mobilizing events. On the contrary, patients who developed hematologic toxicity during induction turned out to be poor mobilizers (OR 3.5, 95% IC 1.36-9.59, p= 0.011). Plerixafor was used in 54/109 patients in the Dara-VTD group and in 16/116 patients of the VTD group. Two patients failed HSC mobilization both with G-CSF and cyclophosphamide and G-CSF. All patients that received G-CSF only resulted in poor mobilizers and required plerixafor before HSC harvest; therefore, cyclophosphamide showed to be superior with regards to G-CSF as mobilizing therapy (p= 0.011). The median number of collected HSC was significantly lower in the Dara-VTD group vs VTD group: 5.17 x 10^6/Kg (IQR 3.9-5.47) vs 8.7 x 10^6/kg (IQR 6.35-11.15), respectively (p &amp;lt; 0.0001). 33% of patients in Dara-VTD group collected at least 6 x 10^6 CD34+/Kg). Median time to neutrophils and platelets engraftment were different between the two groups (13 and 11 days, respectively, P &amp;lt; 0.0001), but we did not observe any difference in terms of infection incidence. Notably, post-transplant infections incidence in Dara-VTD group was 43%. Although the second transplant was planned for 36 patients treated with Dara-VTD, it was performed in 10 patients only, mainly because of insufficient HSC harvest. Conclusions Our experience with Dara-VTD confirms an increased number of poor mobilizers, a higher need for the use of plerixafor and a lower number of collected HSC. We observed a slightly lower engraftment in Dara-VTD group, probably because of a lower number of infused HSC. The lower number of collected HSC hampers the possibility of a double transplant.

A German-Wide Systematic Study on Mobilization and Collection of Hematopoietic Stem Cells in Poor Mobilizer Patients with Multiple Myeloma prior to Autologous Stem Cell Transplantation

Introduction: In patients with a clinical indication for autologous hematopoietic stem cell transplantation (ASCT), sufficient mobilization of CD34+ precursor cells into peripheral blood is essential to ensure adequate hematopoietic stem cell (HSC) collection prior to intensive therapy. However, with standard granulocyte-colony stimulating factor (G-CSF)-based mobilization schemes, an important minority of patients fail to mobilize sufficient (e.g., >10/µL) CD34+ cell counts into the peripheral blood and are considered as poor mobilizers (PM). Because failure to achieve sufficient CD34+ cell mobilization can negatively affect important clinical treatment endpoints, the use of plerixafor (PLX) was approved to increase CD34+ mobilization in PM patients. Methods: The German non-interventional, multicenter, open-label, prospective OPTIMOB study evaluated HSC mobilization strategies prior to planned ASCT in adult patients with hematologic malignancies (lymphomas or multiple myeloma [MM]) focusing on PM patients. PM patients were defined as follows: (1) never achieving ≥20 CD34+ cells/µL before 1st apheresis, (2) receiving PLX at any timepoint of mobilization, (3) their initially planned stem cell yield had to be reduced, or (4) they had not received apheresis due to low CD34+ count in peripheral blood. Results: 168 of 475 MM patients (35%) participating in the OPTIMOB study were classified as PM, and 155 of them (92%) received PLX (PM+PLX) during the study. PM patients were 40–78 years old, slightly more often male (n = 97, 58%), mostly newly diagnosed (n = 146, 87%) and received highly individualized previous treatments. Ninety-four of the PMs underwent chemotherapy mobilization (65%), and 51 patients (35%) received steady-state mobilization with G-CSF only during 1st mobilization attempt. 92% of the total PM population (n = 155) underwent apheresis, 78% of them (n = 117) achieved >2.0 × 106 CD34+ cells/kg body weight on the 1st day of apheresis. PM+PLX had a higher median total collection result than those PM patients without PLX support (7.2 vs. 5.7 × 106 CD34+ cells/kg body weight). In total, ASCT was performed in 136 PM+PLX (88%) versus 8 PM−PLX patients (62%). Conclusion: The OPTIMOB study showed that a considerable proportion of adult MM patients in Germany are PMs. Even though most of PMs were supported with PLX in the OPTIMOB study, PM-PLX also successfully mobilized HSCs, allowing ASCT in majority of all PMs. However, further analyses are required for treatment optimization in PMs.

P‐BT‐18 | Plerixafor‐based Mobilization and Collection of Hematopoietic Stem Cells in Sickle Cell Disease Four Patients in India

P‐BT‐18 | Plerixafor‐based Mobilization and Collection of Hematopoietic Stem Cells in Sickle Cell Disease Four Patients in India

Updates on the mobilization pipeline for hematopoietic stem cell collection.

Hematopoetic Stem Cell Transplantation is a life saving procedure which requires mobilization of stem cells for apheresis procedure. In this review we aimed to examine mobilizing agents that are in use and under investigation. Apheresis practitioners who oversee stem cell collections should be familiar with the recent advances in mobilization agents to utilize most up-to-date information for better patient outcomes.

Use of subgroup-specific hematopoietic stem cell collection efficiencies to improve truncation calculations for large-volume leukapheresis procedures.

A critical component of optimizing peripheral blood (PB) hematopoietic stem cell (HSC) collections is accurately determining the processed blood volume required to collect the targeted number of HSCs. Fundamental to most truncation equations employed to determine this volume is the procedure's estimated collection efficiency (CE), which is typically applied uniformly across all HSC collections. Few studies have explored the utility of using different CEs in subpopulations of donors that have substantially different CEs than the institutional average. Initial procedures from 343 autologous and 179 allogeneic HSC collections performed from 2018 to 2021 were retrospectively analyzed. Predictive equations were developed to determine theoretical truncation rates in various donor subgroups. Quantitative variables (pre-procedure cell counts) and qualitative variables (relatedness to recipient, gender, method of venous access, and mobilization strategy) were found to significantly impact CE. However, much of the variability in CE between donors could not be explained by the variables assessed. Analyses of procedures with high pre-collection PB cell counts identified lower CE values for these donors' truncation equations which still allow truncation but minimize risk of collecting less CD34+ cells than requested. Individualized CE does not substantially improve truncation volume calculations over use of a fixed CE and adds complexity to these calculations. The optimal fixed CE varies between autologous and allogeneic donors, and donors with high pre-collection PB cell counts in either of these groups. This model will be clinically validated and continuously refined through analysis of future HSC collections.

Reducing Microbial Contamination in Hematopoietic Stem Cell Products and Quality Improvement Strategy: Retrospective Analysis of 1996-2021 Data.

Sterility and safety assurance of hematopoietic stem cell (HSC) products is critical in transplantation. Microbial contamination can lead to product disposal and increases the risk of unsuccessful clinical outcomes. Therefore, it is important to implement and maintain good practice guidelines and regulations for the HSC collection and processing unit in each hospital. We aimed to share our experiences and suggest strategies to improve the quality assurance of HSC processing. We retrospectively analyzed microbial culture results of 11,743 HSC products processed over a 25-year period (January 1996 to May 2021). Because of reorganization of the HSC management system in 2008, the 25-year period was divided into periods 1 (January 1996 to December 2007) and 2 (January 2008 to May 2021). We reviewed all culture results of the HSC products and stored aliquot samples and collected culture results for peripheral blood and catheter samples. Of the 11,743 products in total, 35 (0.3%) were contaminated by microorganisms, including 19 (0.5%) of 3,861 products during period 1 and 16 (0.2%) of 7,882 products during period 2. Penicillium was the most commonly identified microorganism (15.8%) during period 1 and coagulase-negative Staphylococcus was the most commonly identified (31.3%) during period 2. HSC product contamination occurred most often during HSC collection and processing. The contamination rate decreased significantly during period 2, when the HSC management system was reorganized. Our results imply that handling HSC products by trained personnel and adopting established protocols, including quality assurance programs, aid in decreasing the contamination risk.

The efficiency of a continuous versus an intermittent apheresis method for collection of hematopoietic progenitor stem cells: A systematic review.

Peripheral blood hematopoietic progenitor stem cells (HPSCs) are the most common source of stem cells for autologous and allogenic transplantation. Currently, systematic reviews comparing the collection efficiency of a continuous to an intermittent method are lacking despite the existence of primary studies. Therefore, the objective of this review was to synthesize the best available evidence to compare the efficiency of the continuous vs the intermittent method for the collection of hematopoietic progenitor stem cells required for HPC transplantation. A search using MEDLINE, CINAHL, EMBASE, Google scholar, and MedNar for both published and unpublished studies was conducted in December 2021. The systematic review was conducted in accordance with JBI methodology. A critical appraisal of the studies was undertaken by two independent reviewers using the JBI quasi-experimental critical appraisal checklist. A total of six studies were included in the review. The findings of this review demonstrated that there was no statistically significant difference in the collection efficiency, length of procedure time, and total blood volume processed between the continuous and intermittent programs. The evidence suggests that the continuous method is as safe and effective as the intermittent method to collect HPSCs. Until further evidence becomes available clinicians should be guided by the policies of their individual hospitals.