Therapeutic relevance of CD34 cell dose in blood cell transplantation for cancer therapy

Autologous peripheral blood stem cell harvest timing by absolute neutrophil count in children and young adult patients: Single-institute experience

BACKGROUND

Myeloablative, high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (PBSCT) improves outcome in some high-risk malignant solid tumors and lymphomas in children and young adults.

METHODS

We performed 16 peripheral blood stem cell (PBSC) harvests in 12 children and 2 young adult patients with a high-risk malignant solid tumor or refractory/relapsed Hodgkin's lymphoma from August 2015 to December 2020. In our chemotherapy mobilization protocol, we used an absolute neutrophil count (ANC) of >1 × 109/L following the nadir after chemotherapy as the criterion for undertaking the apheresis.

RESULTS

The median CD34+ cell count per kg body weight of the 33 apheresis products was 4.92 × 106 cells/kg (range, 0.34-22.53 × 106 cells/kg). Thirteen of the 14 patients (93%) had successful PBSC collections that met their goals for PBSCT. Three patients did not receive PBSCT due to disease progression prior to transplantation. Prompt engraftment occurred in all the remaining 11 patients with 17 PBSCTs.

CONCLUSION

Our data suggest that ANC can be helpful as a surrogate parameter in clinical decision-making when the peripheral blood CD34+ count is unavailable.

SERCA-mediated endoplasmic reticulum stress facilitates hematopoietic stem cell mobilization

BACKGROUND

Hematopoietic stem cell (HSC) transplantation is widely recognized as an effective treatment for various malignant diseases. Enhancing HSC mobilization can improve transplantation outcomes and ultimately increase patient survival rates. Recent studies suggest that mild endoplasmic reticulum (ER) stress promotes HSC self-renewal, anti-apoptotic, and anti-aging capabilities. This led us to investigate whether inducing mild ER stress could facilitate HSC mobilization.

METHODS

The phenotype changes in cells treated with ER stress inducers and Sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) inhibitors were assessed using flow cytometry. The efficacy of these agents on HSC mobilization was evaluated in C57Bl/6 mice, with colony forming unit (CFU) assays used for quantification. Knockdown Jurkat cell lines were constructed to validate the role of SERCA in the mobilization mechanism. Molecular and protein expression levels associated with the pathway were analyzed through quantitative reverse-transcription PCR and western blotting.

RESULTS

Our findings revealed that BHQ, a SERCA inhibitor, efficiently enhanced HSC mobilization in vivo. Mechanistically, BHQ regulated the CaMKII-STAT3-CXCR4 pathway by suppressing SERCA activity. This inhibition led to a reduction in CXCR4 expression on the surface of HSCs, facilitating their migration from the bone marrow into peripheral circulation.

CONCLUSIONS

Our study provides novel insights into the role of the SERCA-ER stress pathway in HSC mobilization. By targeting SERCA activity with BHQ, we observed a significant enhancement in the mobilization of HSCs, facilitated by the modulation of the CaMKII-STAT3-CXCR4 signaling pathway. This research highlights the potential of utilizing mild ER stress as a strategy to promote HSC mobilization, with significant implications for improving stem cell-based therapies, including those used in HSC transplantation.

Discovery of Novel, Potent, Orally Bioavailable and Efficacious, Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitors for Hematopoietic Stem Cell Mobilization

Hematopoietic stem cell (HSC) mobilization is often difficult to achieve in patients suffering from multiple myeloma and non-Hodgkin's lymphoma. Granulocyte-colony stimulating factor (G-CSF) therapy alone has often not led to the desired outcomes. Herein, we describe the discovery of 7-cyclohexyl-4-hydroxy-8-oxo-N-(pyridazin-4-ylmethyl)-7,8-dihydro-2,7-naphthyridine-3-carboxamide 13, a hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor, which was discovered by focusing on drug-like properties. Building on a previous discovery that HIF-PH inhibitors can enhance HSC mobilization in combination with G-CSF, we optimized 13 to exhibit high PHD2 potency, improved solubility, and an optimized PK profile. 13 was effective at enhancing G-CSF-induced HSC mobilization in mice at a dose of 2 mg/kg.

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

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

Adverse impact of delay of platelet recovery after autologous hematopoietic cell transplantation for aggressive non-Hodgkin lymphoma and multiple myeloma

BACKGROUND AIMS

The prognostic impact of platelet recovery after autologous hematopoietic cell transplantation (AHCT) on clinical outcomes remains to be elucidated. We aimed to clarify the impact of platelet recovery on clinical outcomes, risk factors of delayed platelet recovery and the necessary dose of CD34+ cells for prompt platelet recovery in each patient.

METHODS

Using a nationwide Japanese registry database, we retrospectively analyzed clinical outcomes of 5222 patients with aggressive non-Hodgkin lymphoma (NHL) or multiple myeloma (MM).

RESULTS

At a landmark of 28 days after AHCT, a delay of platelet recovery was observed in 1102 patients (21.1%). Prompt platelet recovery was significantly associated with superior overall survival (hazard ratio [HR] 0.32, P < 0.001), progression-free survival (HR 0.48, P < 0.001) and decreased risks of disease progression (HR 0.66, P < 0.001) and non-relapse/non-progression mortality (HR 0.19, P < 0.001). The adverse impacts of a delay of platelet recovery seemed to be more apparent in NHL. In addition to the dose of CD34+ cells/kg, disease status, performance status and the hematopoietic cell transplant-specific comorbidity index in both diseases were associated with platelet recovery. We then stratified the patients into three risk groups according to these factors. For the purpose of achieving 70% platelet recovery by 28 days in NHL, the low-, intermediate- and high-risk groups needed more than 2.0, 3.0 and 4.0 × 106 CD34+ cells/kg, respectively. In MM, the low-risk group needed approximately 1.5 × 106 CD34+ cells/kg, whereas the intermediate- and high-risk groups required 2.0 and 2.5 × 106 CD34+ cells/kg to achieve about 80% platelet recovery by 28 days.

CONCLUSIONS

A delay of platelet recovery after AHCT was associated with inferior survival outcomes.

Mobilization Strategies in Myeloma Patients Intended for Autologous Hematopoietic Cell Transplantation

Background

Multiple myeloma is currently the leading indication for autologous hematopoietic cell transplantation (AHCT). A prerequisite for AHCT is mobilization and collection of adequate blood graft to support high-dose therapy. Current mobilization strategies include granulocyte colony-stimulating factor (G-CSF) alone or in combination with chemotherapy most commonly cyclophosphamide (CY). More recently, plerixafor has become into agenda especially in patients who mobilize poorly. In the selection of a mobilization method, several factors should be considered.

Summary

Preplanned collection target is important as G-CSF plus plerixafor is more effective in the mobilization of CD34+ cells than G-CSF alone. On the other hand, CY plus G-CSF is superior to G-CSF only mobilization. Previous therapy and age of the patients are important considerations as G-CSF alone may not be effective enough in patients with risk factors for poor mobilization. These factors include extensive lenalidomide exposure, irradiation to bone marrow-bearing sites, higher age, or a previous mobilization failure. Also, local preferences and experiences as well as the number of apheresis needed are important issues as well as cost-effectiveness considerations. Mobilization method used may have implication for cellular composition of collected grafts, which might have an impact on posttransplant events such as hematologic and immune recovery in addition to also potential long-term outcomes.

Key Message

Currently, G-CSF alone and preemptive plerixafor if needed might be considered as a standard mobilization strategy in MM patients intended for AHCT.

Trends in utilization of stored cryopreserved autologous peripheral hematopoietic cells intended for a second (or beyond) autologous hematopoietic cell transplantation in patients with multiple myeloma: a single center experience

Due to the advent of effective novel therapies for multiple myeloma (MM), the use of cryopreserved autologous peripheral blood hematopoietic cells (APBHC) for a salvage autologous transplant (auto-HCT) is in decline. We evaluated utilization trends and costs associated with cryopreserved APBHC in patients with MM. We retrospectively evaluated the clinicopathologic data from 440 patients with MM who underwent APBHC mobilization and collection at Mayo Clinic Florida between 2010 and 2019. Based on institution-specific charges as of May 2021, the cost of 1 session of APBHC collection/apheresis was $4,680 and the cost of 1 year of APBHC cryopreservation was $4,790 per patient. Out of 347 patients who had APBHC in cryopreservation, 5 (1.4%) underwent a salvage auto-HCT and 61% of patients had ≥1 excess collection sessions for APBHC that ultimately went unused. The median cost of excess collection sessions was $4,680 per patient (range, $4,680-$32,760) and the median total cost for excess collection sessions plus costs for storage was $23,840 per patient (range, $4,680-$85,450). The sum of costs of excess collection sessions was $2,077,920 and the sum of costs of cryopreservation was $5,812,665. Institutional policies regarding universal APBHC collection and long-term storage should be reevaluated in the era of novel therapeutics.

Long-Term Outcomes of Autologous Hematopoietic Stem Cell Transplant (HSCT) for Multiple Myeloma: While New Horizons Emerge, It Is Still Only a Silver Lining for Resource-Constrained Settings

Background Significant hurdles impede the optimal implementation of hematopoietic stem cell transplantation (HSCT) in low-middle income countries (LMICs). Herein, we highlight the challenges faced in LMICs while performing HSCT and report the long-term outcomes of patients with newly diagnosed multiple myeloma (MM) who underwent autologous HSCT (AHSCT) at our center. Besides, we provide a comprehensive review of studies reporting long-term outcomes of AHSCT in MM from the Indian subcontinent. Methodology This study was conducted at the State Cancer Institute, Sher-i-Kashmir Institute of Medical Sciences, Srinagar, India. Case records of all patients with MM who received AHSCT from December 2010 to July 2018 were reviewed retrospectively. A non-systematic literature search was performed using PubMed and Google Scholar databases. Data regarding clinicopathological parameters and long-term follow-up were extracted from relevant studies and for patients included in our study. Results At our center, 47 patients (median age 52.0 years) with MM underwent AHSCT. Majority of patients had stage III disease (ISS) and median time to transplant was 11.5 months. The five-year progression free survival (PFS) and overall survival (OS) were 59.1% and 81.2%, respectively. Studies from the Indian subcontinent have observed a five-year OS of ~50% to ~85%. However, a greater variability in the five-year PFS has been reported, ranging from ~20% to ~75%. The median time to transplant has ranged from seven to 17 months (indicating time delays) with median CD34 cell counts of 2.7-6.3×106 cells/kg (lower than developed countries). Conclusions Despite significant resource limitations in LMICs, AHSCT is increasingly been performed in MM with encouraging long-term outcomes.

Impact of the number of cryopreserved CD34+ cells in the infused blood grafts on hematologic recovery and survival in myeloma patients after autologous stem cell transplantation: Experience from the GOA study

BACKGROUND

Prospective data on the impact of CD34⁺ cell loss during cryopreservation and the amount of cryopreserved CD34⁺ cells infused after high-dose therapy on hematologic recovery and post-transplant outcome in multiple myeloma (MM) are scarce.

PATIENTS AND METHODS

This post-hoc study aimed to investigate factors associating with CD34⁺ cell loss during cryopreservation and the effects of the infusion of a very low number (<1.0 × 10⁶ /kg, group A), low number (1-1.9 × 10⁶ /kg, group B), and optimal number (≥2 × 10⁶ /kg, group C) of thawed viable CD34⁺ cells on hematologic recovery, progression free survival, and overall survival after autologous stem cell transplantation among 127 patients with MM.

RESULTS

In group C, pegfilgrastim use (P = 0.001), plerixafor use (P = 0.039), and older age ≥ 60 years (P = 0.026) were associated with less loss of CD34⁺ cells during cryopreservation. Better mobilization efficacy correlated with greater CD34⁺ cell loss in group B (P = 0.013 and P = 0.001) and in group C (P < 0.001 and P < 0.001). Early platelet engraftment was slowest in group A (20 d vs 12 d in group B vs 11 d in group C, P = 0.003). The infused viable CD34⁺ cell count <1.0 × 10⁶ /kg seemed not to have influence on PFS (P = 0.322) or OS (P = 0.378) in MM patients.

CONCLUSIONS

Cryopreservation impacts significantly on the CD34⁺ cell loss. A very low number of graft viable CD34⁺ cells did not affect PFS or OS.

Short-Term Storage of Mobilized Peripheral Blood Stem Cells in a Closed System Changes the Microenvironment and May Affect the Quantity of CD34+ and CD34+CD38-CD45RA-CD90+ Cells

Hypoxic conditions preserve the multipotency and self-renewing capacity of murine bone marrow and human cord blood stem cells. Blood samples stored in sealed blood gas tubes become hypoxic as leukocytes metabolize and consume oxygen. Taken together, these observations suggest that peripheral blood stem cell (PBSC) samples stored under airtight conditions become hypoxic, and that the stem cells contained may undergo qualitative or quantitative changes. This study aimed to determine the effect of storage for 8 hours in a sealed system on PBSC samples. Granulocyte colony-stimulating factor-mobilized PBSC samples were collected prospectively from 9 patients with myeloma or amyloidosis prior to apheresis, followed by measurement of CO2, O2, hydrogen ion (pH), lactate, and glucose concentrations in the blood and immunophenotyping of stem cell and multipotent progenitor cell populations before and after 8 hours of storage in sealed blood collection tubes. Blood concentrations of O2 and glucose and pH measurements were significantly decreased, whereas concentrations of CO2 and lactate were significantly increased after storage. Significantly higher concentrations of CD34+ cells (552 ± 84 cells/106 total nucleated cells [TNCs] versus 985 ± 143 cells/106 TNCs; P = .03), CD34+CD38- cells (98 ± 32 cells/106 TNCs versus 158 ± 52 cells/106 TNCs; P = .03), CD34+CD38+ cells (444 ± 92 cells/106 TNCs versus 789 ± 153 cells/106 TNCs; P = .03), and CD34+CD38-CD45RA-CD90+ cells (55 ± 17 cells/106 TNCs versus 89 ± 25 cells/106 TNCs; P = .02) were detected after 8 hours of storage. The changes in concentrations of CD34+CD38+ cells and CD34+ cells were inversely associated with the change in glucose concentration (P = .003 and P < .001, respectively) and positively associated with the change in lactate concentration (P = .01 and P <.001, respectively) after 8 hours of airtight storage. Storage of PBSC samples in a sealed, airtight environment is associated with microenvironmental changes consistent with hypoxia and increased concentrations of immunophenotypically defined stem cells. These results may have clinical implications with regard to the collection and processing of stem cell products and warrant confirmation with functional and mechanistic studies.

Development and validation of a predictive model to guide the use of plerixafor in pediatric population

Plerixafor, a CXCR4 receptor antagonist, reduces the binding and chemotaxis of hematopoietic stem cells to the bone marrow stroma, resulting in predictable peak of cluster of differentiation 34⁺ (CD34⁺) cells in the peripheral blood (PB) approximately 10 h after its administration. We developed a model that could predict the CD34⁺ harvest volume on the first day of apheresis (AP-CD34⁺) based on PB-CD34⁺ counts immediately prior to commencing apheresis in pediatric population. In all, data from 45 pediatric patients from the MOZAIC study who received either granulocyte colony-stimulating factor (G-CSF) alone or G-CSF plus plerixafor were included. The modeling of the data exhibited a strong and highly predictive linear relationship between the counts of PB-CD34⁺ cells on the first day of apheresis and AP-CD34⁺ cells collected on the same day. It is predicted that there are approximately 13 new collected CD34⁺ cells for 100 new circulating CD34⁺ cells before apheresis. Our predictive algorithm can be used to quantify the minimal count of PB-CD34⁺ cells that enables to collect at least 2 × 10⁶ or 5 × 10⁶ AP-CD34⁺ cells/kg with sufficient assurance (probability = 0.90) and can guide the use of plerixafor in patients at higher perceived risk for mobilization failure. Trial registration of MOZAIC study: ClinicalTrials.gov, NCT01288573; EudraCT, 2010-019340-40.

Meeting the COVID challenge: Optimizing vCD34+ in cryopreserved HPC samples for implementation of an external QA Program

Background

The COVID-19 pandemic has forced a fundamental change in the global procurement of allogeneic hematopoietic progenitor cells (HPCs) for transplantation. To better meet the emergent challenges of transporting cryopreserved allogeneic HPC during pandemics, there is an urgent need for External Quality Assurance (EQA) programs to evaluate reproducibility and harmonization of viable CD34⁺ cell (vCD34⁺) HPC enumeration, as the current EQA programs are unsuitable for analysis of vCD34⁺. The cost-effective distribution of HPC cryopreserved reference samples (CRSs) with acceptable reproducibility and specificity is key to the success of a vCD34⁺ EQA program.

Methods

Cryopreserved HPC samples (n = 11) were either stored on dry ice for 1 to 4 days or for 1 day followed by liquid nitrogen (LN) storage for 1 to 3 days to assess optimal conditions for vCD34⁺ EQA. Flow cytometric enumeration of vCD34⁺ HPCs was performed using a single platform assay combined with 7-AAD viability dye exclusion. The optimum transportation condition was validated in pilot and multicenter national studies (n = 12).

Results

A combination of 1 day on dry ice followed by LN storage stabilized viability compared with continuous storage on dry ice. This study demonstrates that dispatch of CRSs on dry ice to recipient centers across a distance of ≤4000 km within 26 h, followed by LN storage, resulted in reproducible intercenter vCD34⁺ enumeration. The estimated cost of safer and more convenient dry ice delivery is >20-fold lower than that of LN.

Conclusion

This approach can form the basis for economically and scientifically acceptable distribution of CRSs for external vCD34⁺ EQA.

High-Dose Chemotherapy With Autologous Stem Cell Transplantation in a Case of Refractory Peripheral T Cell Lymphoma With Tracheoesophageal Fistula: A Case Report

A 46-year-old woman with a sore throat was diagnosed with anaplastic lymphoma kinase-negative anaplastic large cell lymphoma that had spread from the piriform fossa to the cervical esophagus. Tracheoesophageal fistula developed after induction chemotherapy. Because conservative repair was not applicable, intensified chemotherapy, including autologous stem cell transplantation was performed with the fistula remaining open. Laryngopharyngectomy and cervical esophagectomy were performed 6 months after transplantation. The optimal strategy for refractory lymphoma with active tracheoesophageal fistula remains undetermined. To the best of our knowledge, this is the first report describing the successful treatment of a patient with tracheoesophageal fistula who received high-dose chemotherapy supported by autologous stem cell transplantation.

Prophylactic Peripheral Blood Stem Cell Collection in Patients with Extensive Bone-Marrow Infiltration of Neuroendocrine Tumours Prior to Peptide Receptor Radionuclide Therapy with 177Lu-DOTATATE

Peptide receptor radionuclide therapy (PRRT) of metastatic neuroendocrine tumors (NET) can be successfully repeated but may eventually be dose-limited. Since ¹⁷⁷Lu-DOTATATE dose limitation may come from hematological rather than renal function, hematological peripheral blood stem cell backup might be desirable. Here, we report our initial experience of peripheral blood stem-cell collection (PBSC) in patients with treatment-related cytopenia and therefore high risk of bone-marrow failure. Five patients with diffuse bone-marrow infiltration of NET and relevant myelosuppression (≥grade 2) received PBSC before one PRRT cycle with ¹⁷⁷Lu-DOTATATE (7.6 ± 0.8 GBq/cycle). Standard stem-cell mobilization with Granulocyte-colony stimulating factor (G-CSF) was applied, and successful PBSC was defined as a collection of >2 × 10⁶/kg CD34+ cells. In case of initial failure, Plerixafor was administered in addition to G-CSF prior to apheresis. PBSC was successfully performed in all patients with no adverse events. Median cumulative activity was 44.8 GBq (range, 21.3-62.4). Three patients had been previously treated with PRRT, two of which needed the addition of Plerixafor for stem-cell mobilization. Only one of five patients required autologous peripheral blood stem-cell transplantation during the median follow up time of 28 months. PBSC collection seems to be feasible in NET with bone-marrow involvement and might be worth considering as a backup strategy prior to PRRT, in order to overcome dose-limiting bone-marrow toxicity.

Comparison of CD34+ cell mobilization, blood graft cellular composition, and post-transplant outcome in myeloma patients mobilized with filgrastim or pegfilgrastim added to low-dose cyclophosphamide: A prospective multicenter study

BACKGROUND

Scarce data exist on the impact of granulocyte-colony stimulating factor (G-CSF) type on the mobilizing capacity of CD34⁺ cells, graft cellular composition, and outcome in myeloma (MM) patients.

PATIENTS AND METHODS

In this prospective multicenter study, 70 patients with MM received filgrastim (FIL) and 20 patients received pegfilgrastim (PEG) as a G-CSF after low-dose cyclophosphamide. Flow cytometry was used to analyze the mobilization of CD34⁺ cells and cellular composition of blood grafts, hematologic recovery, and survival after auto-SCT according to the G-CSF choice.

RESULTS

The CD34⁺ cell yield of the first apheresis was higher in the FIL group (5.3 vs. 4.2 × 10⁶ /kg, p = .025). The better mobilizing capacity was observed in the FIL group especially after bortezomib-based induction based on the higher first apheresis yield of CD34⁺ cells (7.5 vs. 4.4 × 10⁶ /kg, p = .001). The median CD19⁺ cell count (1.0 vs. 0.4 × 10⁶ /kg, p = .010) and the number of CD3⁺ T lymphocytes (43.1 vs. 31.8 × 10⁶ /kg, p = .122) in the infused graft were higher in the patients mobilized with FIL. Both early (day +15) (56 vs. 108 × 10⁹ /L, p = .002) and later platelet recovery at 6 months (191 vs. 226 × 10⁹ /L, p = .026) were faster in the PEG group.

CONCLUSION

G-CSF type seems to impact on the mobilization capacity and cellular composition of infused graft and also platelet recovery post-transplant. A randomized study might be warranted to verify the effects of G-CSF choice in the mobilization field.

Prediction of Stem Cell Mobilization Failure in Patients with Hodgkin and Non-Hodgkin Lymphoma

Objective:

Autologous stem cell transplantation (ASCT) is a significant and potentially curative treatment modality for patients with relapsed/refractory lymphoma. Insufficient mobilization and harvest of peripheral stem cells can be a major obstacle for performing ASCT. The aim of this study was to evaluate the factors that might influence mobilization failure in patients with lymphoma.

Materials and Methods:

Eighty-seven patients diagnosed with non-Hodgkin and Hodgkin lymphoma who underwent stem cell mobilization afterwards at the Hacettepe University Medical School Bone Marrow Transplantation Center, Turkey, between the years of 2000 and 2018 were evaluated.

Results:

A total of 87 patients were included in this study. In 66 of 87 patients (75.9%), the first mobilization trial was successful. Adequate (≥2x106/kg) CD34+ cells were collected in the first apheresis for 66 patients (9.5±8.1). For 21 of 87 (24.1%), the first mobilization trial was unsuccessful. Therefore, a second mobilization trial was performed for these patients with plerixafor (5.5±3.3). The number of CD34+ cells was significantly higher in patients who were successful in the first mobilization (p=0.002).

Conclusion:

The success rate of the first mobilization trial was found to be higher in patients with high platelet counts before mobilization and patients who received chemotherapy-based mobilization protocols. In the patients who had mobilization failure in the first trial, plerixafor was used in a later mobilization, and those patients had an adequate amount of stem cells for ASCT. Parameters predicting mobilization failure would allow for preemptive, more cost-effective use of such agents during the first mobilization attempt; however, risk factors for mobilization failure are still not clear.

Use of Plerixafor for Stem Cell Mobilization in the Setting of Autologous and Allogeneic Stem Cell Transplantations: An Update

Mobilization failure is an important issue in stem cell transplantations. Stem cells are yielded from the peripheral blood via apheresis. Granulocyte colony-stimulating factor (G-CSF) is the most commonly used mobilization agent among patients and donors. G-CSF is administered subcutaneously for multiple days. However, patients with mobilization failure cannot receive autologous stem cell transplantation and, therefore, cannot be treated adequately. The incidence rate of mobilization failure among patients is about 6–23%. Plerixafor is a molecule that inhibits the binding of chemokine receptor-4 with stromal-cell-derived factor-1, thereby resulting in the release of CD34+ cells in the peripheral blood. Currently, plerixafor is used in patients with mobilization failure with G-CSF and is administered subcutaneously. Several studies conducted on different clinical settings have shown that plerixafor is effective and well tolerated by patients. However, more studies should be conducted to explore the optimal approach for plerixafor in patients with mobilization failure. The incidence of mobilization failure among donors is lower. However, plerixafor is not approved among donors with mobilization failure. Moreover, several clinical studies in donors have shown a beneficial effect of plerixafor. In addition, the adverse events of plerixafor are mild and transient, which can overcome the adverse events due to G-CSF. This review assessed the current role and effects of plerixafor in stem cell mobilization for autologous and allogeneic stem cell transplantations.

Optimizing leukapheresis product yield and purity for blood cell-based gene and immune effector cell therapy

PURPOSE OF REVIEW

A critical common step for blood-based ex-vivo gene and immune effector cell (IEC) therapies is the collection of target cells for further processing and manufacturing, often accomplished through a leukapheresis procedure to collect mononuclear cells (MNCs). The purpose of this review is to describe strategies to optimize the apheresis product cell yield and purity for gene and IEC therapies. Relevant data from the conventional bone marrow transplant literature is described where applicable.

RECENT FINDINGS

Product yield is affected by three main factors: the peripheral blood concentration of the target cell, optimized by mobilizing agents, donor interventions or donor selection; the volume of peripheral blood processed, tailored to the desired product yield using prediction algorithms; and target cell collection efficiency, optimized by a variety of device and donor-specific considerations. Factors affecting product purity include characteristics of the donor, mobilizing agent, device, and device settings.

SUMMARY

Strategies to optimize product yield and purity for gene and IEC therapies are important to consider because of loss of target cell numbers or function with downstream steps and detrimental effects of nontarget cells on further manufacturing and patient outcome.

Autograft cellular composition and outcome in myeloma patients: Results of the prospective multicenter GOA study

BACKGROUND

Autologous stem cell transplantation (auto-SCT) is a widely used treatment option in multiple myeloma (MM) patients. The optimal graft cellular composition is not known.

STUDY DESIGN AND METHODS

Autograft cellular composition was analyzed after freezing by flow cytometry in 127 MM patients participating in a prospective multicenter study. The impact of graft cellular composition on hematologic recovery and outcome after auto-SCT was evaluated.

RESULTS

A higher graft CD34⁺ cell content predicted faster platelet recovery after auto-SCT in both the short and long term. In patients with standard-risk cytogenetics, a higher graft CD34⁺ count (>2.5 × 10⁶ /kg) was linked with shorter progression-free survival (PFS; 28 vs. 46 months, p = 0.04), but there was no difference in overall survival (OS) (p = 0.53). In a multivariate model, a higher graft CD34⁺ CD133⁺ CD38^- (>0.065 × 10⁶ /kg, p = 0.009) and NK cell count (>2.5 × 10⁶ /kg, p = 0.026), lenalidomide maintenance and standard-risk cytogenetics predicted better PFS. In contrast, a higher CD34⁺ count (>2.5 × 10⁶ /kg, p = 0.015) predicted worse PFS. A very low CD3⁺ cell count (≤20 × 10⁶ /kg, p = 0.001) in the infused graft and high-risk cytogenetics remained predictive of worse OS.

CONCLUSIONS

Autograft cellular composition may impact outcome in MM patients after auto-SCT. More studies are needed to define optimal graft composition.

Impact of infused CD34+ stem cell dosing for allogeneic peripheral blood stem cell transplantation with post-transplant cyclophosphamide

Higher infused total nucleated cell dose (TNC) in allogeneic bone marrow transplant (BMT) with post-transplant cyclophosphamide (PTCy) is associated with improved overall survival. As many centers prefer peripheral blood stem cell grafts (PBSCT) with PTCy, the effect of cell dose on outcomes with this platform also requires elucidation. We retrospectively evaluated 144 consecutive adult patients who received allogeneic T-cell replete PBSCT with PTCy-based graft-versus-host disease (GVHD) prophylaxis for a hematologic malignancy from 2012-2018. The infused CD34+ cell dose was stratified into low (<5 × 10⁶/kg), intermediate (5-10 × 10⁶/kg) and high (>10 × 10⁶/kg) dose level groups. In multivariate analysis, the low CD34+ cell dose group had worse non-relapse mortality (HR = 4.51, 95% CI: 1.92-10.58, p < 0.001), progression- free survival (HR = 4.11, 95% CI: 2.07-8.15, p < 0.001), and overall survival (HR = 4.06, 95% CI: 2.00-8.25, p ≤ 0.001) compared to the intermediate group. Clinical outcomes between the intermediate and high CD34+ cell dose groups were similar. TNC and CD3+ cell dose had no significant impacts on outcomes. These findings suggest that, in patients receiving allogeneic PBSCT with PTCy, infused CD34+ cell doses >5 × 10⁶ cells/kg may result in improved survival. Thus, this study supports targeting a CD34+ cell dose of >5 × 10⁶ cells/kg for allogeneic PBSCT with PTCy.

Promise of autologous CD34+ stem/progenitor cell therapy for treatment of cardiovascular disease

CD34+ cells are haematopoietic stem cells used therapeutically in patients undergoing radiation or chemotherapy due to their regenerative potential and ability to restore the haematopoietic system. In animal models, CD34+ cells have been associated with therapeutic angiogenesis in response to ischaemia. Several trials have shown the potential safety and efficacy of CD34+ cell delivery in various cardiovascular diseases. Moreover, Phase III trials have now begun to explore the potential role of CD34+ cells in treatment of both myocardial and peripheral ischaemia. CD34+ cells have been shown to be safe and well-tolerated in the acute myocardial infarction (AMI), heart failure, and angina models. Several studies have suggested potential benefit of CD34+ cell therapy in patients with coronary microvascular disease as well. In this review, we will discuss the therapeutic potential of CD34+ cells, and describe the pertinent trials that have used autologous CD34+ cells in no-options refractory angina, AMI, and heart failure. Lastly, we will review the potential utility of autologous CD34+ cells in coronary endothelial and microvascular dysfunction.

Immune Reconstitution after Haploidentical Donor and Umbilical Cord Blood Allogeneic Hematopoietic Cell Transplantation

Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy for a variety of hematologic diseases. However, this therapeutic platform is limited by an initial period when patients are profoundly immunocompromised. There is gradual immune recovery over time, that varies by transplant platform. Here, we review immune reconstitution after allogeneic HCT with a specific focus on two alternative donor platforms that have dramatically improved access to allogeneic HCT for patients who lack an HLA-matched related or unrelated donor: haploidentical and umbilical cord blood HCT. Despite challenges, interventions are available to mitigate the risks during the immunocompromised period including antimicrobial prophylaxis, modified immune suppression strategies, graft manipulation, and emerging adoptive cell therapies. Such interventions can improve the potential for long-term overall survival after allogeneic HCT.

CD34+ hematopoietic progenitor cell dose as a predictor of engraftment and survival in multiple myeloma patients undergoing autologous stem cell transplantation

Background/aim

High-dose melphalan and autologous hematopoietic stem cell transplantation (AHSCT) is the standard treatment strategy for multiple myeloma (MM) patients who are eligible for it. The recommended dose of CD34+ hematopoietic progenitor cells (HPCs) for adequate engraftment is above 2 × 106/kg. The aim of this study was to evaluate the relationship between the dose of CD34+HPCs and survival in MM patients who underwent AHSCT at a tertiary care center.

Materials and methods

Enrolled in this study were 271 MM patients who underwent AHSCT between 2003 and 2019. Clinical characteristics of the patients, disease status pre-AHSCT, reinfused CD34+ cell doses, and neutrophil and platelet engraftment days were recorded, retrospectively. The patients were divided into 2 groups according to whether the dose of reinfused CD 34+ HPCs was <5 × 106/kg or ≥5 × 106/kg. The groups were compared in terms of engraftment and overall survival (OS) times.

Results

The median age of the patients was 54.8 (33–76) years. The median dose of infused CD34+ HPCs was 5.94 × 106/kg (1.47–59.5 × 106/kg). The median follow-up period was 54 months (4–211). The median OS of the patients was 103 months (11–144). The median neutrophil and platelet engraftment time was 10 (8–24) and 11 (7–40) days. Doses of <5 × 106/kg and ≥5 × 106/kg CD34+ HPC were reinfused in 38.1% and 61.9% of the patients, respectively. There was a negative significant correlation between the reinfused CD34+cell level and neutrophil/platelet engraftment times (r = –0.32, P < 0.001; r = –0.27, P < 0.001, respectively). The median OS times were observed as 103 months (11–144) and 145 months (123–166) for patients who had been administered <5 × 106/kg and ≥5 × 106/kg of CD34+ HPCs, respectively (P = 0.009).

Conclusion

The increased amount of CD34+ autologous hematopoietic stem cell dose after high dose melphalan chemotherapy in MM patients shortened the platelet and neutrophil engraftment time and increased OS. Early platelet engraftment and administration of a CD34+ HPC count that is ≥5 × 106/kg can be considered as predictors of better survival in patients.

Analysis of laboratory parameters for optimal autologous peripheral blood stem cell collection from lymphoma and myeloma patients

BACKGROUND

Peripheral blood stem cell (PBSC) collection is important for successful hematopoietic stem cell transplantation. This study aimed to investigate the laboratory parameters associated with the optimal timing of autologous PBSC collection from lymphoma and multiple myeloma patients.

METHODS

We retrospectively evaluated data from 1105 PBSC apheresis procedures performed on 379 adult patients at the National Cancer Center between June 2005 and December 2019. Laboratory parameters, including cutoff values for the number of hematopoietic progenitor cells (HPCs) and circulating CD34+ cells, were analyzed to determine their association with CD34+ cell yield.

RESULTS

The pre-apheresis HPC and CD34+ cell count were statistically significant variables associated with harvested CD34+ cell in lymphoma and MM patients. The optimal cutoff values were 18 × 10⁶ /L for pre-HPC count (66.8% sensitivity, 66.4% specificity) and 11/μL for pre-CD34+ cell count (85.8% sensitivity, 87.2% specificity), to achieve CD34+ cell yields ≥ 1.0 × 10⁶ /kg for each apheresis procedure. Moreover, the optimal cutoff values were 23 × 10⁶ /L for pre-HPC count (71.0% sensitivity, 69.0% specificity) and 18/μL for pre-CD34+ cell count (87.5% sensitivity, 86.3% specificity) to achieve CD34+ cell yields ≥ 2.0 × 10⁶ /kg for each apheresis procedure.

CONCLUSION

HPC count is a potential surrogate marker for monitoring the starting time for PBSC collection. Applying cutoff values for the number of HPC and CD34+ cells may be clinically useful for optimizing the timing of PBSC collection.

Mobilization characteristics, blood graft composition, and outcome in diffuse large B-cell lymphoma after autologous stem cell transplantation: Results from the prospective multicenter GOA study

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is a common indication for autologous stem cell transplantation (auto-SCT).

STUDY DESIGN AND METHODS

This prospective noninterventional study aimed to evaluate the impact of mobilization characteristics and graft cellular content on hematologic recovery and outcome after auto-SCT among 68 patients with DLBCL.

RESULTS

Better mobilization capacity as manifested by blood CD34⁺ cell count >32 × 10⁶ /L and CD34⁺ cell yield of the first apheresis >2.75 × 10⁶ /kg correlated with faster neutrophil (P = .005 and P = .017) and platelet (P = .002 and P < .001) recovery. A higher number of infused CD34⁺ cells (> 2.65 × 10⁶ /kg) was associated with better 5-year overall survival (OS; 95% vs 67%, P = .012). The graft CD34⁺ CD133⁺ CD38^- cell count >0.07 × 10⁶ /kg was predictive of better 5-year OS (87% vs 63%; P = .008) and higher graft CD3⁺ cell count (>23.1 × 10⁶ /kg) correlated also with better 5-year OS (80% vs 40%, P = .008). In multivariate analysis only disease status of CR I at auto-SCT was associated with better progression-free survival (P = .014) and OS (P = .039).

CONCLUSION

The mobilization capacity of CD34⁺ cells impacted on early hematologic recovery in patients with DLBCL after auto-SCT. Higher graft CD34⁺ cell count and both CD34⁺ CD133⁺ CD38^- and CD3⁺ cells were also associated with better OS. The effect of optimal graft cellular composition on outcome in DLBCL should be evaluated in a randomized study.

How I manage frontline transplant-eligible multiple myeloma in Italy

The treatment of transplant-eligible multiple myeloma patients in Italy consists in an induction phase based on bortezomib plus thalidomide plus dexamethasone (VTd), followed by a single or tandem autologous stem cell transplantation (ASCT), followed by lenalidomide maintenance. This approach offers an overall response rate of 93% and a CR rate of 58% with acceptable toxicity. Lenalidomide maintenance adds a significant increase in disease control, with a progression free survival after ASCT of 53 months, and an overall survival of 86 months. Second primary malignancies represent the most concerning toxicity of lenalidomide maintenance with a 6.9% incidence. However, the benefit in terms of increased myeloma control largely outweigh this complication. The incorporation of daratumumab in this treatment schema will further improve these clinical results.

Factors that predict delayed platelet recovery after autologous stem cell transplantation for lymphoma or myeloma

The amount of infused CD34⁺ cells has been reported to be the strongest predictor of platelet recovery after autologous stem cell transplantation (ASCT). However, the timing of platelet recovery varies widely among patients even after the infusion of similar amounts of CD34⁺ cells. Therefore, we retrospectively assessed 99 patients who underwent their first ASCT for lymphoma or myeloma at our center. Thirteen patients (13%) did not achieve platelet engraftment, defined as a platelet count of at least 2.0 × 10⁴/μL without transfusion, at day 28 after transplantation, whereas 58 of 60 patients (97%) who received at least 2.0 × 10⁶/kg CD34⁺ cells achieved platelet engraftment within 28 days. Multivariate analysis identified the following significant risk factors for delayed platelet recovery: hemoglobin level and platelet count before stem cell harvest, body temperature of > 39 °C within 5 days after ASCT, and infusion of a small amount (< 2.0 × 10⁶/kg) of CD34⁺ cells. In a subgroup analysis of 39 patients infused with < 2.0 × 10⁶/kg CD34⁺ cells, a need for repeated apheresis for stem cell harvest and a body temperature of > 39 °C within 5 days after ASCT were identified as independent factors for delayed platelet recovery. In summary, platelet recovery following ASCT was affected by insufficient hematopoietic recovery at stem cell harvest, a need for repeated apheresis, and high fever early after ASCT, particularly when the amount of infused stem cells was insufficient.

Efficacy and safety of stem cell mobilization following gemcitabine, dexamethasone, cisplatin (GDP) salvage chemotherapy in patients with relapsed or refractory lymphoma

High-dose chemotherapy and autologous stem cell transplant (ASCT) remains a cornerstone of treatment in relapsed/refractory (R/R) aggressive-histology lymphomas. This retrospective study examined efficacy and safety of peripheral blood stem cell (PBSC) mobilization using cyclophosphamide/etoposide and GCSF (CE + GCSF, n = 129) versus gemcitabine, dexamethasone and cisplatin and GCSF (GDP + GCSF, n = 210). All patients received first salvage with GDP. Patients mobilized with CE + GCSF required fewer days of leukapheresis (median 1 vs 2 day; p = .001) and achieved higher total CD34+ yield than GDP + GCSF patients (8.5 vs 7.1 × 10⁶ CD34+ cells/kg, p = .001). Rates of febrile neutropenia and CD34+ collection ≥5 × 10⁶ CD34+ cells/kg were similar (OR 1.19, 95% CI: 0.54-2.6, p = .66). In multivariable analysis, days to engraftment and admission duration were not statistically different between the two mobilization strategies. While CE + GCSF appeared more efficacious for mobilization after GDP salvage, this did not translate to significant differences in clinical outcomes.

Apheresis machines variably overestimate mononuclear cell collection volume

INTRODUCTION

Calculation of the actual number of CD34+ cells in the collection product is based on the volume of the collected product and its concentration of CD34+ cells measured in the lab. The number of CD34+ cells infused correlates closely with the pace of hematopoietic reconstitution following autologous or allogeneic stem cell transplantation.

METHODS

We studied peripheral blood stem cell collections in a single apheresis center with two Spectra Optia devices, using mononuclear cell collection or continuous mononuclear cell collection procedures. The collection volume displayed by the apheresis device was compared with the volume determined by a weight-based method.

RESULTS

Fifty-two consecutive CD34 collections in 35 different donors (range 1-4 daily procedures per donor) were analyzed. The machines reported larger collection volumes (P < .001). The mean collection volume reported by the machine was 274.37 mL (range 162-396). The mean manually measured collection volume was 261.82 mL (range 155-371.40). Mean overestimation by machine was 12.53 mL (range -0.95 to 31.24; 95% confidence interval 10.94-14.11) or 4.88% (range -0.26 to 10.28). Median overestimation of the absolute number of CD34 was 10.29 × 10⁶ (range -2.83 to 141.84 × 10⁶ ).

CONCLUSION

Both Spectra Optia machines overestimated the collection volume after peripheral blood stem cell collection. Although the mean variation falls within the expected range, in some cases, this overestimation may be clinically relevant if no other method of measurement is used.

Immune profiling in diffuse large B-cell lymphoma and mantle cell lymphoma patients treated with autologous hematopoietic cell transplant

This is the first longitudinal study of immune profiles and autologous hematopoietic cell transplant (AHCT) survival in B-cell non-Hodgkin lymphoma (B-NHL) patients and the effect of plerixafor mobilization on immune reconstitution in this population. A comprehensive immunophenotyping panel was performed in 104 consecutive adult B-NHL patients (58% diffuse large B-cell, 42% mantle cell) who received AHCT (1/2008-11/2014), at a median of 28 days pre-AHCT (N=104) and Day+100 (N=83) post-AHCT. Median follow-up post-AHCT was 61 months (range: 8-120 months). Compared to patients mobilized with filgrastim and plerixafor, patients mobilized with filgrastim alone had a higher proportion of CD4+ naïve (p=0.006) and CD8+ central memory T-cells (p=0.006) pre-AHCT. For patients transplanted in complete remission (CR), a higher proportion of CD8+ effector memory T-cells pre-AHCT was associated with worse progression-free survival (PFS; p<0.01) and overall survival (OS; p<0.01). A higher ratio of CD8:CD4+ central memory T-cells pre-AHCT was associated with worse PFS (p<0.0001) and OS (p=0.0034). This same ratio measured post-AHCT among patients in CR on Day+100 was associated with worse and OS (p=0.008) but not PFS (p=not significant). These immune subsets are complementary biomarkers which identify patients transplanted in CR who have poor survival prognoses and may warrant further clinical interventions.

Hematopoietic Differentiation of Human Pluripotent Stem Cells: HOX and GATA Transcription Factors as Master Regulators

Numerous human disorders of the blood system would directly or indirectly benefit from therapeutic approaches that reconstitute the hematopoietic system. Hematopoietic stem cells (HSCs), either from matched donors or ex vivo manipulated autologous tissues, are the most used cellular source of cell therapy for a wide range of disorders. Due to the scarcity of matched donors and the difficulty of ex vivo expansion of HSCs, there is a growing interest in harnessing the potential of pluripotent stem cells (PSCs) as a de novo source of HSCs. PSCs make an ideal source of cells for regenerative medicine in general and for treating blood disorders in particular because they could expand indefinitely in culture and differentiate to any cell type in the body. However, advancement in deriving functional HSCs from PSCs has been slow. This is partly due to an incomplete understanding of the molecular mechanisms underlying normal hematopoiesis. In this review, we discuss the latest efforts to generate human PSC (hPSC)-derived HSCs capable of long-term engraftment. We review the regulation of the key transcription factors (TFs) in hematopoiesis and hematopoietic differentiation, the Homeobox (HOX) and GATA genes, and the interplay between them and microRNAs. We also propose that precise control of these master regulators during the course of hematopoietic differentiation is key to achieving functional hPSC-derived HSCs.

Plerixafor for patients who fail cytokine-or chemotherapy-based stem cell mobilization: Results of a prospective study by the Polish Lymphoma Research Group (PLRG)

Autologous hematopoietic stem cell transplantation (autoHSCT) requires collection of sufficient number of hematopoietic stem cells. The goal of this study was to evaluate efficacy of plerixafor used in patients with lymphoid malignancies failing conventional stem cell mobilization.

This was a prospective, non-interventional study. All consecutive patients (n = 109) treated with plerixafor in 11 centers were reported. The drug was used either in case of previous mobilization failure (n = 67) or interventionally, in case of insufficient CD34+ cell output during current mobilization (n = 42). Successful mobilization was defined as resulting in collection of ≥ 2 × 106 CD34+ cells/kg for single autoHSCT or ≥ 4 × 106 CD34+ cells/kg for double procedure.

The overall rate of successful mobilization was 55% (55% for single and 56% for double autoHSCT). The median total number of collected CD34+ cells/kg was 2.4 (range, 0-11.5) for patients intended for a single transplantation while 4.0 (0.6-16.9) for double procedure. The number of circulating CD34+ cells increased after the use of plerixafor regardless of baseline values. The median fold increase was 3.3 (0.3-155). Data from this observational study confirm high efficacy of plerixafor used in routine clinical practice as salvage for patients with lymphoid malignancies failing conventional stem cell mobilization.

Comparison of filgrastim, pegfilgrastim, and lipegfilgrastim added to chemotherapy for mobilization of CD34+ cells in non-Hodgkin lymphoma patients

BACKGROUND

Data are limited on the long-acting granulocyte-colony stimulating factors (G-CSFs) pegfilgrastim (PEG) and lipegfilgrastim (LIPEG) compared with filgrastim (FIL) regarding the mobilization efficiency of CD34⁺ cells, graft cellular composition, and engraftment.

STUDY DESIGN AND METHODS

In this prospective nonrandomized study, 36 patients with non-Hodgkin lymphoma received FIL, 67 received PEG, and 16 patients received LIPEG as a cytokine after chemotherapy. We analyzed the mobilization and collection of CD34⁺ cells, cellular composition of blood grafts, and hematologic recovery after auto-SCT according to the type of G-CSF used.

RESULTS

Patients in the LIPEG group had fewer apheresis sessions (1 vs. 2, p = 0.021 for FIL and p = 0.111 for PEG) as well as higher median blood CD34⁺ cell counts at the start of the first apheresis (LIPEG 74 × 10⁶ /L vs. FIL 31 × 10⁶ /L, p = 0.084 or PEG 27 × 10⁶ /L, p = 0.021) and CD34⁺ yields of the first apheresis (FIL 5.1 × 10⁶ /kg vs. FIL 2.3 × 10⁶ /kg, p = 0.105 or PEG 1.8 × 10⁶ /kg, p = 0.012). Also, the costs associated with G-CSF mobilization and apheresis were lower in the LIPEG group. The graft composition was comparable except for the higher infused CD34⁺ cell counts in the LIPEG group. The engraftment kinetics were significantly slower in the FIL group.

CONCLUSION

LIPEG appears to be more efficient compared with PEG after chemotherapy to mobilize CD34⁺ cells for auto-SCT demonstrated as fewer sessions of aphereses needed as well as 2.8-fold CD34⁺ cell yields on the first apheresis day. Early hematologic recovery was more rapid in the LIPEG group. Thus further studies on LIPEG in the mobilization setting are warranted.

Impact of good and poor mobilizers on hematopoietic progenitor cell collection efficiency and product quality

BACKGROUND

Mobilization regimen choice is a significant contributing factor for successful hematopoietic progenitor cell (HPC) collection by leukocytapheresis and reaching the target CD34+ cell dose. How mobilization regimen affects collection efficiency and the quality of products collected using the Spectra Optia apheresis instrument is not fully known.

METHODS

We evaluated the impact of granulocyte-colony stimulating factor (GCSF) and GCSF/plerixafor mobilization regimens on CE and product composition. We studied 373 leukocytapheresis HPC collections for 147 autologous transplants from January 1, 2010 to December 31, 2014. Patients were categorized in two groups; good mobilizers, mobilized with GCSF only (GM) and poor mobilizers, mobilized with GCSF and Plerixafor (PM).

RESULTS

Overall, compared with PM group, total nucleated cell (TNC) yield was significantly lower in GM group (P = <.001). In contrast, median percent mononuclear cell (MNC) collected from GM (86.5%) was significantly higher than products collected from PM group (79.5%; P < .001). Compared with GM group, CD34+ cell CE was about 10% lower in PM group (P < .008). In addition, daily CD34+ cell/Kg yield was significantly higher in GM (2.08 × 10/Kg) compared with PM group (1.64 x 10/Kg, P = .019). Overall, the median number of collections per patient was two for GM and three for PM (P = .004).

CONCLUSION

Products collected from PM group contained higher TNC content relative to GM group but had lower MNC enrichment, CD34+ cell CE and daily CD34+ cell yield per Kg.

Does Reinfusion of Stem Cell Products on Multiple Days Affect Engraftment?

Objective:

High-doses of melphalan treatment with autologous stem cell transplantation in multiple myeloma (MM) remains a major treatment modality in suitable patients. A minimal dose of 2x10⁶/kg CD34+ cells is preferred to achieve engraftment. Some patients need multiple leukapheresis procedures to achieve the necessary number of CD34+ cells, but this can cause a high volume of stem cell product that cannot be given in a single day. Whether or not the number of infusion days affects engraftment has not been studied before. We aimed to evaluate the impact of reinfusion of stem cells on multiple days on engraftment results.

Materials and Methods:

Demographic features, CD34+ cell doses, neutrophil and platelet engraftment days, hospitalization days, and number of infusion days of 149 autologous transplantations of 143 MM patients were evaluated retrospectively.

Results:

The data of 143 MM patients who were transplanted were analyzed retrospectively. Median age was 55±8.5 (range: 26-70) years with a male/female ratio of 91/58. Hospitalization days for all patients were 24±6 (range: 14-50) days. Mean CD34+ cell number was (7.5±5.3)x10⁶/kg (range: 1.5-31x10⁶/kg). CD34+ cells were reinfused in 1 day in 80.5% (n=120) of the patients, 2 days in 18.2% of the patients (n=27), and 3 days in 1.3% of the patients (n=2). For 29 patients, reinfusion was applied in more than 1 day because of the high volume of stem cell product. We did not see any dimethyl sulfoxide toxicity, cardiac arrhythmia, or volume overload complications. Hypertensive attacks during infusion were easily controlled by furosemide treatment. In the group with multiple infusions, the infused CD34+ cell numbers had a mean of (4.8±2.8)x10⁶/kg, and in the single infusion group the mean was (8.1±5.5)x10⁶/kg. There were no statistical differences between the two groups regarding platelet and neutrophil engraftment days (p=0.850, r=0.820 and p=0.500, r=0.440). There was no statistical difference between the two groups for hospitalization days (p=0.060, r=0.050).

Conclusion:

In cases with a high volume of stem cell product to acquire adequate stem cells, reinfusion can be safely applied across multiple days without any delay in engraftment.

The relationship between CD34+ stem cell dose and time to neutrophil recovery in autologous haematopoietic stem cell recipients-A single centre experience

A retrospective, observational study was performed of 112 patients who underwent autologous haematopoietic stem cell transplantation (ASCT) to determine the relationship between CD34+ stem cell dose and neutrophil engraftment. Importantly, a novel approach to more accurately calculate time to neutrophil engraftment was employed. The results demonstrated that a higher CD34+ stem cell dose was associated with faster neutrophil recovery (P < 0.05). CD34+ stem cell dose using actual and ideal patient body weight were both equally predictive of neutrophil engraftment as were absolute and viable CD34+ measurements. The clinical implications for this relationship are limited with an increase in CD34+ stem cell dose by 1 × 10⁶/kg reducing the neutrophil engraftment time by only 3 h and 50 min. The median time to neutrophil recovery was 217 h (9 days and 1 h) and this relatively early engraftment time may be related to an early initiation of granulocyte colony-stimulating factor (G-CSF) on day +1 post-transplant. Female patients engrafted 17 h faster than their male counterparts on multi-variate analysis (P < 0.05). Conditioning chemotherapy, bacteraemia, G-CSF dose/kg body weight and increasing age had no impact on time to neutrophil recovery.

Differences in Transplant-Related Complications between Hematologic Malignancies and Solid Tumors Receiving High-Dose Chemotherapy and Autologous Peripheral Blood Stem Cell Transplantation

Multiple factors contribute to transplant-related complications after high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation, including conditioning regimens, number of infused stem cells and clinical characteristics of patient at transplant. We compared the transplant-related complications of 141 patients affected with hematological malignancies with those of 109 patients with solid tumors. The total number of peripheral blood stem cell transplantations performed was 339. High-dose chemotherapy mainly consisted of melphalan-, busulphan- or thiotepa-based regimens. Despite the equal number of infused CD34+ cells, patients with a hematological malignancy showed a slower absolute neutrophil count (days to neutrophils >0.5 x 109/L, 10.6 ± 3.6 for hematological malignancies versus 9.1 ± 1.2 for solid tumors, P <0.0001) and platelet recovery (days to platelets >20 x 109/L, 16.4 ± 9.8 for hematological malignancies versus 12.3 ± 4.1 for solid tumors, P <0.0001) than patients with a solid tumor. A significantly higher requirement of red blood cell (3.3 ± 4.1 versus 2.0 ± 1.9, P <0.0029) and platelet units (7.5_± 10.4 versus 4.2 ± 3.4, P <0.0001) was observed for hematological malignancies than for solid tumors. Five graft failures were documented exclusively in patients with a hematological malignancy. Moreover, such patients displayed a longer duration of mucositis (P <0.0028) and hospital stay (P <0.0001), but no difference was observed in terms of febrile episodes. Transplant-related mortality was similar between the two groups. In conclusion, patients with a hematological malignancy overall have more complications than those with a solid tumor.

Salvage Treatment with Epirubicin and/or Paclitaxel in Metastatic Breast Cancer Patients Relapsed after High-dose Chemotherapy with Peripheral Blood Progenitor Cells

Aims and Background

To evaluate feasibility and efficacy of paclitaxel as a single agent or in combination with epirubicin in breast cancer taxane-naive patients who have failed previous high-dose chemotherapy.

Methods

Since February 1995, we have treated 32 patients in first relapse or progression after high-dose chemotherapy. Nineteen patients had metastatic breast cancer, 12 more than 3 involved axillary lymph nodes, and 1 inflammatory breast cancer at inclusion to the program. The median time to relapse after high-dose chemotherapy was 12 months (range, 2-43). At relapse, 12 patients were treated with epirubicin (90 mg/m2) plus paclitaxel (175 mg/m2) administered on day 1 every 21 days. In 20 patients who had previously received more than 350 mg/m2 of a cumulative dose of epirubicin and in one patient pretreated with chemotherapy containing mitoxantrone, we employed paclitaxel (175 mg/m2) alone. A median number of five courses was administered (range, 2-10).

Results

The overall response rate after 3 courses (29 of 32 patients were assessable) was 55% and after 6 courses (21 of 32 patients were assessable) was 57%. The median time to progression was 7 months (95% CI, 5.7-9.2), and median survival was 27.5 months (95% CI, 17.8-37.0). Toxicity was recorded for 180 cycles (epirubicin + paclitaxel for 62 cycles and paclitaxel alone for 118 cycles). The main toxicity in both regimens was hematologic. We observed WHO grade 3-4 neutropenia (in 8 patients, 25%), for which G-CSF (5 μg/kg/day sc) was employed. WHO grade 3-4 thrombocytopenia occurred in 2 patients (6%) and WHO grade 3 anemia in 1 patient (3%).

Conclusions

Our study showed that paclitaxel (alone or in combination with epirubicin) is feasible as salvage treatment in heavily pretreated patients.

Phase I/II Study of Intravenous Plerixafor Added to a Mobilization Regimen of Granulocyte Colony-Stimulating Factor in Lymphoma Patients Undergoing Autologous Stem Cell Collection

Plerixafor, given subcutaneously with granulocyte colony-stimulating factor (G-CSF), improves autologous stem cell collection in patients with lymphoma and multiple myeloma. Intravenous (i.v.) administration of plerixafor allows administration of plerixafor on the same day as pheresis and it may improve stem cell collection. The primary objectives of this phase I/II study were to determine the maximum tolerated dose of i.v. plerixafor and the efficacy of i.v. plerixafor + G-CSF to mobilize ≥ 2 × 106 CD34+ cells/kg from patients with lymphoma. In phase I, 25 patients were treated with G-CSF + i.v. plerixafor at escalating doses; in phase II, 36 patients were treated with G-CSF + plerixafor .40 mg/kg. The treatment was well tolerated. Fifty-nine of 61 patients (98%) met the collection goal and 47 of 61 patients (77%) collected ≥ 5.0 × 106 CD34+ cells/kg in a median of 2 pheresis days. Analysis of CD34+ hematopoietic stem and progenitor cells (HSPCs) revealed that G-CSF-mobilized grafts were enriched with CD34+CD45RA-CD123+/- primitive HSPCs whereas plerixafor preferentially mobilized CD34+CD45RA+CD123++ plasmacytoid dendritic cell precursors. In conclusion, i.v. plerixafor is well tolerated and effective when added to G-CSF for the mobilization of stem cells from patients with lymphoma, with mobilization kinetics and stem cell collections that compare favorably with subcutaneous dosing.

Comparison of Different Stem Cell Mobilization Regimens in AL Amyloidosis Patients

High-dose melphalan (HDM) and autologous blood stem cell transplantation (ABSCT) is an effective treatment for transplantation-eligible patients with systemic light chain (AL) amyloidosis. Whereas most centers use granulocyte colony-stimulating factor (G-CSF) alone for mobilization of peripheral blood stem cells (PBSC), the application of mobilization chemotherapy might offer specific advantages. We retrospectively analyzed 110 patients with AL amyloidosis who underwent PBSC collection. Major eligibility criteria included age <70 years and cardiac insufficiency New York Heart Association ≤III°. Before mobilization, 67 patients (61%) had been pretreated with induction therapy, including 17 (15%) patients who had received melphalan. Chemo-mobilization was performed with either cyclophosphamide, doxorubicin, dexamethasone (CAD)/G-CSF (n = 78, 71%); ifosfamide/G-CSF (n = 14, 13%); or other regimens (n = 8, 7%). AL amyloidosis patients with predominant heart involvement and/or status post heart transplantation were mobilized with G-CSF only (n = 10, 9%). PBSC collection was successful in 101 patients (92%) at first attempt. The median number of CD34⁺ cells was 8.7 (range, 2.1 to 45.5) × 10⁶ CD34⁺/kg collected in a median of 1 leukapheresis (LP) session. Compared with G-CSF-only mobilization, a chemo-mobilization with CAD/G-CSF or ifosfamide/G-CSF had a positive impact on the number of collected CD34⁺ cell number/kg per LP (P <.001, multivariate). Melphalan-containing previous therapy and higher age had a significant negative impact on quantity of collected CD34⁺ cells. Median common toxicity criteria (CTC) grade of nonhematologic toxicity was II (range, 0 to IV). Life-threatening CTC grade IV adverse events were observed in 3 patients with no fatalities. Cardiovascular events were observed in 17 patients (22%) upon CAD/G-CSF mobilization (median CTC: grade 3; range, 1 to 4). Toxicity in patients undergoing ifosfamide/G-CSF mobilization was higher than in with those who received G-CSF-only mobilization. HDM and ABSCT were performed in 100 patients. Compared with >6.5 × 10⁶ transplanted CD34⁺ cells/kg, an ABSCT with <3 × 10⁶ CD34⁺ cells/kg was associated with a longer duration to leukocyte reconstitution >1 × 10⁹/L and a reduced platelet count <150 × 10⁹/L 1 year after ASCT. Our results show that CAD chemotherapy is very effective in PBSC mobilization and has a tolerable toxicity profile in AL amyloidosis patients. A further toxicity reduction by omission of doxorubicin might be considered. Because of advanced nonhematologic toxicity, ifosfamide administration cannot be recommended. However, G-CSF mobilization alone is also safe and effective. Considering the hematopoietic reconstitution and long-term stem cell function, our results provide a rationale to collect and transplant as many as >6.5 × 10⁶ CD34⁺ cells/kg, if feasible with reasonable effort.

[Impact of Her2 and BRCA1/2 status in high-dose chemotherapy and autologous stem cells transplantation in the treatment of breast cancer: The Institut Paoli Calmettes' experience]

INTRODUCTION

Studies evaluating chemotherapy high dose chemotherapy with autologous haematopoietic stem cell transplantation (HDC-ACSH) in the treatment of metastatic (MBC), locally advanced (LABC) and inflammatory (IBC) breast cancer have in common lack of biomarker information, in particular the HER2 status.

PATIENTS AND METHODS

All consecutive female patients treated for breast cancer with HDC and AHSCT at Institut Paoli Calmettes between 2003 and 2012 were included. Patients were categorized in three subtypes based on hormonal receptor (HR) and HER2 status of the primary tumor: luminal, (HR+/HER2-), HER2 (HER2+, any HR) and triple negative (TN) (HER2- and HR-). The main objective was the analysis of overall survival (OS) according to the IHC subtypes.

RESULTS

Three hundred and seventy-seven patients were included. For MBC, the TN subtype appeared to have the worst prognosis with a median OS of 19.68 months (95 % CI 11.76-44.4) compared to 44.64 months (95 % CI 40.32-67.56) for the luminal subtype and a median OS not reached for the HER2 subtype (P<0.01). For IBC, HER2 subgroup appeared to have the best prognosis with a 5-year OS of 89 % (95 % CI 64-97) compared to 57 % (95 % CI 33-76) for the TN subgroup (HR 5.38, 95 % CI 1.14-25.44; P=0.034). For CSLA, luminal subgroup appeared to have the best prognosis with a 5-year OS of 92 % (95 % CI 71-98) against 75 % (95 % CI 46-90) for HER 2 subtype and 70 % (95 %CI 97-88) for TN subtype (P=0.301).

CONCLUSION

The HDC-ACSH does not change the prognosis value of IHC subtype in breast cancer patients.

Graft Immune Cell Composition Associates with Clinical Outcome of Allogeneic Hematopoietic Stem Cell Transplantation in Patients with AML

Complications of allogeneic hematopoietic stem cell transplantation (HSCT) have been attributed to immune cells transferred into the patient with the graft. However, a detailed immune cell composition of the graft is usually not evaluated. In the present study, we determined the level of variation in the composition of immune cells between clinical HSCT grafts and whether this variation is associated with clinical outcome. Sizes of major immune cell populations in 50 clinical grafts from a single HSCT Centre were analyzed using flow cytometry. A statistical comparison between cell levels and clinical outcomes of HSCT was performed. Overall survival, acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), and relapse were used as the primary endpoints. Individual HSCT grafts showed considerable variation in their numbers of immune cell populations, including CD123⁺ dendritic cells and CD34⁺ cells, which may play a role in GVHD. Acute myeloid leukemia (AML) patients who developed aGVHD were transplanted with higher levels of effector CD3⁺ T, CD19⁺ B, and CD123⁺ dendritic cells than AML patients without aGVHD, whereas grafts with a high CD34⁺ content protected against aGVHD. AML patients with cGVHD had received grafts with a lower level of monocytes and a higher level of CD34⁺ cells than those without cGVHD. There is considerable variation in the levels of immune cell populations between HSCT grafts, and this variation is associated with outcomes of HSCT in AML patients. A detailed analysis of the immune cell content of the graft can be used in risk assessment of HSCT.

How do we mobilize and collect autologous peripheral blood stem cells?

Autologous stem cell transplantation (ASCT) with mobilized peripheral blood stem cells (PBSCs) has become a widely applied therapeutic approach for many hematologic and nonhematologic diseases. Adequate PBSC mobilization is critical to the success of ASCT. However, many factors can contribute to poor mobilization. Plerixafor is an effective yet costly adjunct agent that has been increasingly used to improve mobilization in a variety of diagnoses and clinical settings. However, to achieve both optimal cell collection yields and cost-effectiveness, the role of plerixafor in PBSC mobilization needs to be well defined in terms of triggers for initiating its use and criteria for monitoring response. As one of the largest hematopoietic transplant centers in the country, we have developed an approach to PBSC mobilization and collection that incorporates patient laboratory assessments, monitoring of the collection yields, and judicious use of plerixafor as well as various patient support and education programs. These measures have resulted in an increase in our collection success rate and a decrease in the mean number of collection days. In this article we describe our approach to autologous PBSC mobilization and collection. Pertinent reports in the literature are also reviewed and discussed.