Efficient mobilization of peripheral blood stem cells following CAD chemotherapy and a single dose of pegylated G-CSF in patients with multiple myeloma

An evidence-based and risk-adapted GSF versus GSF plus plerixafor mobilization strategy to obtain a sufficient CD34+ cell yield in the harvest for autologous stem cell transplants

BACKGROUND

Plerixafor is a bicyclam molecule with the ability to reversibly bind to receptor CXCR-4 thus leading to an increased release of stem cells (SC) into the circulation. This study aims to evaluate the efficacy of G-CSF plus plerixafor versus G-CSF alone mobilizing regimens on the basis of CD34+ cell yield and engraftment kinetics following hematopoietic SC transplants.

METHODS

The study incorporated 173 patients with plasma cell neoplasms (PCN), Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), undergoing mobilization and following autologous SC-transplant. For patients with mobilization failure and those predicted to be at risk of harvesting inadequate CD34+ yields (poor-responders), plerixafor was administered. Data was collected and compared in relation to the harvesting protocols used, cell quantification, cell-engraftment potential and overall clinical outcome.

RESULTS

A total of 101 patients received plerixafor (58.4 %) and the median CD34+increase was 312 %. Chemotherapy-mobilized PCN-patients required less plerixafor administration (p = 0.01), no difference was observed in lymphoma groups (p = 0.46). The median CD34+cell yield was 7.8 × 106/kg bm. Patients requiring plerixafor achieved lower, but still comparable cell yields. Total cell dose infused was in correlation with engraftment kinetics. Patients requiring plerixafor had delayed platelet engraftment (p = 0.029).

CONCLUSIONS

Adequately selected plerixafor administration reduces "mobilization-related-failure" rate and assure a high-level cell dose for SC transplants, with superior "therapeutic-potential" and safety profile. The mobilization strategy that incorporates "just-in-time" plerixafor administration, also leads to a reduction of hospitalization days and healthcare resource utilization. For definitive conclusions, further controlled/larger clinical trials concerning correlation of CD34+ cell count/yield, with hematopoietic reconstitution are required.

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.

A multinational, drug utilization study of lipegfilgrastim use in real-world setting in Europe

PURPOSE

Lipegfilgrastim (Lonquex, Teva Pharma B.V.) is approved for reduction in neutropenia duration and febrile neutropenia incidence. In the framework of lipegfilgrastim regulatory approval in the EU, the Health Authorities requested a drug utilization study. This study was conducted to characterize prescribing patterns of lipegfilgrastim and quantify the extent of on- and off-label use of lipegfilgrastim in real-world setting in Europe.

METHODS

Information on lipegfilgrastim use between January 2014 and March 2020 was abstracted from medical records in hospital and outpatient clinical settings. Indication for lipegfilgrastim was classified either as on-label or off-label use according to pre-determined criteria. The primary endpoint was the extent of lipegfilgrastim off-label use based on the most recent lipegfilgrastim cycle.

RESULTS

Records of 481 patients were obtained from five European countries. Lipegfilgrastim was most commonly prescribed for prevention of neutropenia by oncologists and hematologists. Patients who were administered lipegfilgrastim were primarily ≥ 55 years old (65.1%) and female (65.7%). The most frequent underlying diagnosis was breast cancer (38.3%). For the most recent lipegfilgrastim cycle, on-label use was recorded in 452/459 patients with no missing data (98.5%), while off-label use was recorded in 7/459 patients (1.5%). The majority of off-label use was attributed to use with non-cytotoxic chemotherapy (57.1%). Off-label use of lipegfilgrastim across all treatment cycles with no missing data was 11/1547 cycles (0.7%).

CONCLUSION

Using real-world data, these findings confirm the low rate of lipegfilgrastim off-label use as reported in a preceding feasibility study, indicating very high adherence to the approved indication.

Safety and Effectiveness of Plerixafor for Peripheral Blood Stem Cell Mobilization in Autologous Stem Cell Transplantation: Results of a Post-Marketing Surveillance Study

Background

Plerixafor was approved in Japan in 2016 for peripheral blood stem cell (PBSC) mobilization in autologous stem cell transplantation (A-SCT).

Objective

Our objective was to evaluate the safety and effectiveness of plerixafor in Japanese patients undergoing A-SCT for various indications in real-world practice.

Patients and Methods

This post-marketing surveillance study included Japanese patients initiating PBSC mobilization with plerixafor for A-SCT. Safety assessments included the incidence of adverse events (AEs) including serious AEs, adverse drug reactions (ADRs), and laboratory variables. Effectiveness assessments were the proportion of patients with the target CD34+ cell yield (≥2 × 10⁶ cells/kg) ≤4 days after plerixafor administration and the number of days required to reach the target CD34+ cell yield.

Results

In total, 785 patients were registered, and the safety and effectiveness analysis sets comprised 764 and 717 patients, respectively. ADRs occurred in 12.2% of patients, with gastrointestinal disorders (5.5%), laboratory investigations (4.5%), and blood and lymphatic system disorders (3.0%) being the most common. A total of 71.1% of patients had the target CD34+ cell yield within ≤4 days of treatment, with a mean (standard deviation) of 1.3 (0.7) days to reach the target CD34+ cell yield. Over 80% of patients with a baseline CD34+ cell count >2 cells/μL had a target CD34+ cell yield within ≤4 days of treatment.

Conclusions

This large post-marketing surveillance study provided real-world evidence detailing the safety and effectiveness of plerixafor for PBSC mobilization in Japanese patients undergoing A-SCT. Importantly, no new safety concerns were identified, and the safety profile of plerixafor was consistent with the established profile of this drug.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00276-1.

Pegfilgrastim improves the outcomes of mobilization and engraftment in autologous hematopoietic stem cell transplantation for the treatment of multiple myeloma

Autologous stem cell transplantation (ASCT) is the only curable therapy for multiple myeloma (MM), while its success primarily relies on mobilization to obtain sufficient hematopoietic stem/progenitor cells (HPC). Although the role of Pegfilgrastim (PEG), a novel PEGylated form of the recombinant G-CSF filgrastim (FIL), in mobilization has been demonstrated, it remains unclear whether this approach is cost-effective in MM treatment. Here, we performed a real-world analysis to evaluate the efficacy and cost of PEG for mobilization in a cohort of MM patients, of which 53% carried high-risk cytogenetic abnormalities. A total of 91 patients who received either a single dose of PEG (6 or 12 mg, n = 42) or multiple dosing of 10 μg/kg/day FIL (n = 49) after chemotherapy for HPC mobilization were included. The yield of MNCs and CD34⁺ cells per milliliter of blood collected via apheresis was significantly greater in the PEG group than that in the FIL group (P = 0.014 and P = 0.038). Mobilization with PEG yielded significantly higher median number of collected CD34⁺ cells than FIL (5.56 vs. 4.82 × 10⁶/kg; P = 0.038). Moreover, the average time-to-recovery of leukocytes and platelets after transplantation was markedly shorter in the PEG group than that in the FIL group (leukocyte, 11.59 ± 1.98 vs 12.93 ± 2.83 days, P = 0.019; platelet, 12.86 ± 2.62 vs 14.80 ± 5.47, P = 0.085). However, the total cost of mobilization and apheresis using PEG or FIL was comparable (P = 0.486). Of note, mobilization with 12 mg PEG further shortened time-to-recovery of leukocytes (10.64 ± 0.51 vs. 12.04 ± 2.26 days, P = 0.05) and platelets (10.60 ± 2.89 vs. 13.33 ± 2.35 days, P = 0.031) compared with 6 mg PEG. Our results support a notion that PEG (especially 12 mg) combined with chemotherapy is a cost-effective and convenient regimen of mobilization, which might improve the outcome of ASCT in MM.

Mobilization and Collection of Peripheral Blood Stem Cells in Adults: Focus on Timing and Benchmarking

Peripheral blood stem cells (PBSCs) are preferentially used as a hematopoietic stem cell source for autologous blood stem cell transplantation (ABSCT) upon high-dose chemotherapy (HDT) in a variety of hemato-oncologic diseases. As a prerequisite, hematopoietic stem cells have to be mobilized into the peripheral blood (PB) and collected by leukapheresis (LP). Despite continuous improvements, e.g., the introduction of plerixafor, current challenges are the further optimization regarding the leukapheresis procedure, preventing collection failures, as well as benchmarking and harmonization of mobilization approaches between institutions.This chapter summarizes the current PBSC mobilization and collection approaches and is focusing on timely orchestration of mobilization therapy, granulocyte colony-stimulating factor (G-CSF) application, and peripheral blood (PB) CD34⁺ cell assessment. Moreover, strategies for prediction and performance assessment of the PBSC collection yield are discussed.

Mobilization of Hematopoietic Progenitor Cells for Autologous Transplantation Using Pegfilgrastim and Plerixafor: Efficacy and Cost Implications

Filgrastim (FIL) is the most common growth factor combined with plerixafor for autologous hematopoietic progenitor cell mobilization, but requires daily, multi-injection administration. We adopted a standardized mobilization regimen with pegfilgrastim (PEG) and upfront plerixafor, allowing for a single injection given the long half-life and slow elimination of PEG. Between 2015 and 2017, a total of 235 patients with lymphoma or plasma cell dyscrasias underwent mobilization with PEG 6 mg on day 1 and upfront plerixafor 24 mg on day 3, followed by apheresis on day 4 regardless of peripheral blood CD34⁺ cells. The median CD34⁺ cells/mm³ in peripheral blood on first day of collection was 48 and median collection yield was 7.27 × 10⁶ CD34⁺ cells/kg (range, 0.32 to 39.6 × 10⁶ CD34⁺ cells/kg) after a mean of 1.6 apheresis collections. Overall, 83% of patients achieved the mobilization target, and 95% reached the minimum necessary CD34⁺ cell yield to proceed with transplantation (2 × 10⁶ CD34⁺ cells/kg). Because FIL is weight-based and dosed daily, the cost comparison with PEG is influenced by patient weight and number of apheresis sessions required. A cost simulation using actual patient data indicates that PEG is associated with lower cost than FIL for the majority of patients. Autologous hematopoietic progenitor cell mobilization with PEG and plerixafor is practical, effective, and not associated with increased cost compared with FIL mobilization.

Orchestration of Chemomobilization and G-CSF Administration for Successful Hematopoietic Stem Cell Collection

Successful collection of peripheral blood stem cells (PBSCs) depends on the optimal orchestration of mobilization chemotherapy, granulocyte colony stimulating factor (G-CSF) application, and CD34⁺ cell number assessment in the peripheral blood (PB). However, determining the optimal timing in accordance to the applied chemomobilization regimen can be challenging. Although most centers apply their own local timing schedules, a reliable timetable including the currently most often used mobilization regimens is lacking. We present a comprehensive analysis of the timing modalities for 11 of the most commonly used chemomobilization regimens. A retrospective analysis was performed on the clinical and PBSC collection parameters (including duration of G-CSF application, time point of CD34⁺ assessment, PB CD34⁺ cell count, number of leukapheresis [LP] sessions, processed blood volume, and CD34⁺ collection results) of 91 representatively selected patients who had undergone stem cell mobilization at 2 collection centers. Six to 10 patients were analyzed per regimen with a variety of diagnoses, including multiple myeloma, malignant lymphoma, and sarcoma. No collection failures (<2 × 10⁶ CD34⁺ cells/kg body weight) were observed. All analyzed patients successfully reached their individual collection goal in adherence to the given schedule of chemotherapy, application of G-CSF, measurement of CD34⁺ cells, and subsequent LP. The presented data on the timing of chemomobilization, G-CSF application, and stem cell collection may be helpful in clinical decision making and contribute to a more transparent and predictable treatment process.

Pegylated Filgrastim Versus Filgrastim for Stem Cell Mobilization in Multiple Myeloma After Novel Agent Induction

BACKGROUND

The current standard of care for transplant-eligible myeloma patients is novel agent-based induction, followed by high-dose chemotherapy and autologous stem cell rescue. Chemo-mobilization of peripheral blood CD34⁺ stem cells (PBSCs) with pegylated filgrastim (pegfilgrastim), a sustained-duration formulation of filgrastim, has been used as an alternative to filgrastim in several studies involving heterogeneous cohorts of lymphoma and multiple myeloma (MM) patients and shown to be equivalent in PBSC yield and cost-effectiveness. The present study focused on the efficacy of pegfilgrastim in PBSC mobilization compared with filgrastim exclusively after novel agent-based induction in a homogeneous group of MM patients.

PATIENTS AND METHODS

We analyzed the data from 89 patients with MM treated at 2 transplant centers in Singapore who had received novel agent-based induction chemotherapy, PBSC mobilization with vinorelbine/cyclophosphamide, high-dose melphalan conditioning, and autologous stem cell rescue. Of the 89 patients, 61 were included in the pegfilgrastim group and 28 in the filgrastim group, with a similar median age and disease characteristics. PBSC harvesting was performed at a similar median time of 9.51 ± 0.84 days for both, and the peak peripheral blood CD34⁺ stem cell count was 19.90 × 10⁶/kg for pegfilgrastim and 32.50 × 10⁶/kg for filgrastim (95% confidence interval, -4.36 to 0.70 × 10⁶/kg).

RESULTS

No significant difference was found in the median PBSC collection between the 2 groups (pegfilgrastim, 7.90 × 10⁶/kg vs. filgrastim, 10.10 × 10⁶/kg; P = .16).

CONCLUSION

The present study has demonstrated that a single dose of pegfilgrastim is comparable to filgrastim in terms of the timing and efficacy of PBSC harvest and could potentially spare the patient 6 days of filgrastim injections. In addition, ours is the first study to compare these growth factors using vinorelbine/cyclophosphamide as mobilization chemotherapy.

Pegylated granulocyte-colony stimulating factor versus non-pegylated granulocyte-colony stimulating factor for peripheral blood stem cell mobilization: A systematic review and meta-analysis

Granulocyte-colony stimulating factor (G-CSF) mobilizes and increases the amount of hematopoietic stem cells in peripheral blood, enabling its harvest by few apheresis procedures. The pegylated G-CSF has longer half-life and is given once only, which is more comfortable for patients, whereas the non-pegylated requires multiple daily injection because of its short half-life. We summarized results of randomized trials comparing the efficacy and safety of pegylated and non-pegylated G-CSF for peripheral blood stem cell mobilization. We searched the Cochrane CENTRAL, MEDLINE, EMBASE, and two conference proceedings. Two authors made the selection, extracted data and evaluated methodological quality using GRADE independently. We used random-effects model for meta-analysis. We found 3956 records and retrieved 47 full texts. We included eight randomized trials with a total number of 554 randomized and 532 analyzed subjects. The meta-analysis included five trials because not all trials reported the same outcomes. Pooling data from two studies shows no evidence for a difference in the successful mobilization rate (CD34+ cell ≥ 2 × 10⁶ /kg collected) between pegfilgrastim 6 mg (early administration) and filgrastim 5 µg/kg/day (147 participants; risk ratio (RR) 0.87, 95% confidence interval (95%CI) 0.67-1.11; P = .26). Pooling data from three studies shows no difference in the incidence of adverse events between pegylated and non-pegylated G-CSF (170 participants; RR 0.86, 95%CI 0.34-2.17; P = .75). No difference found on the quantity of CD34+ cells collected, number of apheresis procedure in successful mobilization, level of peak PB CD34+ cells achieved, and day of neutrophil and platelet engraftment.

Pegfilgrastim vs filgrastim in PBSC mobilization for autologous hematopoietic SCT: a systematic review and meta-analysis

Trial outcomes comparing cytokine agents for PBSC mobilization in autologous hematopoietic transplant patients have been controversial. We performed a systematic review and meta-analysis of evidence available on pegfilgrastim vs filgrastim in chemo-cytokine mobilization. Electronic literature searches of PubMed, EMBASE and CENTRAL identified nine articles eligible for qualitative analysis with one randomized controlled trial. Eight articles involving 719 patients were included in the meta-analysis. Results showed similar CD34+ cell collection yields for pegfilgrastim and filgrastim (SDM -0.08, 95% CI: -0.388 to 0.228). On comparison with filgrastim, pegfilgrastim showed a significantly earlier apheresis onset time (SDM: -0.512, 95% CI: -0.973 to -0.050) and reduction in required apheresis procedures (SDM -0.260, 95% CI: -0.466 to -0.054). Times to leukocyte (⩾1.0 × 10(9)/L) and platelet (⩾20 × 10(9)/L) recovery were similar between groups (SDM: 0.015, 95% CI: -0.41 to 0.44 and SDM: 0.309, 95% CI: -0.11 to 0.72, respectively). Both agents were well tolerated and mild bone pain was the most frequently reported adverse event. Pegfilgrastim may be a convenient alternative to filgrastim in PBSC mobilization for multiple myeloma and lymphoma patients, but further studies are required to clarify effects of cytokine dosage and previous cytotoxic exposure in specific subpopulations.

R-ESHAP plus pegfilgrastim as an effective peripheral stem cell mobilization regimen for autologous stem-cell transplantation in patients with relapsed/refractory diffuse large B-cell lymphoma

Stem cell (SC) mobilization is significantly influenced by the mobilization schedule in patients with lymphoma. We evaluated data from 30 patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) undergoing SC mobilization. All received R-ESHAP plus a single dose of pegfilgrastim. All patients collected ⩾ 2 × 10(6) CD34+cells/kg, 80% of them at least 5 × 10(6) CD34+cells/kg. Adverse effects of the regimen included myelosuppression and neutropenic fever. Herein, our results suggest that R-ESHAP plus pegfilgrastim is a highly effective mobilization strategy in patients affected by DLBCL associated with a low incidence of adverse events.

Optimizing autologous stem cell mobilization strategies to improve patient outcomes: consensus guidelines and recommendations

Autologous hematopoietic stem cell transplantation (aHSCT) is a well-established treatment for malignancies such as multiple myeloma (MM) and lymphomas. Various changes in the field over the past decade, including the frequent use of tandem aHSCT in MM, the advent of novel therapies for the treatment of MM and lymphoma, and the addition of new stem cell mobilization techniques, have led to the need to reassess current stem cell mobilization strategies. Mobilization failures with traditional strategies are common and result in delays in treatment and increased cost and resource utilization. Recently, plerixafor-containing strategies have been shown to significantly reduce mobilization failure rates, but the ideal method to maximize stem cell yields and minimize costs associated with collection has not yet been determined. A panel of experts convened to discuss the currently available data on autologous hematopoietic stem cell mobilization and transplantation and to devise guidelines to optimize mobilization strategies. Herein is a summary of their discussion and consensus.

Pegfilgrastim compared with filgrastim for cytokine-alone mobilization of autologous haematopoietic stem and progenitor cells

Haematopoietic stem and progenitor cells (HSPC) mobilization, using cytokine-alone, is a well-tolerated regimen with predictable mobilization kinetics. Single-dose pegfilgrastim mobilizes HSPC efficiently; however, there is surprisingly little comparative data on its use without chemotherapy for HSPC mobilization. Pegfilgrastim-alone and filgrastim-alone mobilization regimens were compared in 52 patients with haematological malignancy. Pegfilgrastim 12 mg (n=20) or 6 mg (n=2) was administered Day 1 (D1) in 22 patients (lymphoma n=17; myeloma n=5). Thirty historical controls (lymphoma n=18; myeloma n=12) received filgrastim 10 mcg/kg daily from D1. Peripheral blood (PB) CD34(+) counts reached threshold (5 × 10(6)/L) and apheresis commenced on D4(4-5) and D4(4-6). Median PB CD34(+) cell count on D1 of apheresis was similar (26.0 × 10(6)/L (2.5-125.0 × 10(6)/L) and 16.2 × 10(6)/L (2.6-50.7 × 10(6)/L); P=0.06), for pegfilgrastim and filgrastim groups, respectively. Target yield (2 × 10(6) per kg CD34(+) cells) was collected in 20/22 (91%) pegfilgrastim patients and 24/30 (80%) in the filgrastim group (P=0.44), in a similar median number of aphereses (3(1-4) versus 3(2-6), respectively; P=0.85). A higher proportion of pegfilgrastim patients tended to yield 4 × 10(6) per kg CD34(+) cells; 16/22 (73%) versus 14/30 (47%) filgrastim patients (P=0.09). One pegfilgrastim patient developed hyperleukocytosis that resolved without incident. Pegfilgrastim-alone is a simple, well-tolerated, and attractive option for outpatient-based HSPC mobilization with similar mobilization kinetics and efficacy to regular filgrastim.

Autologous Hematopoietic Stem Cell Transplantation for Multiple Myeloma without Cryopreservation

High-dose chemotherapy followed by autologous hematopoietic stem cell transplantation is considered the standard of care for multiple myeloma patients who are eligible for transplantation. The process of autografting comprises the following steps: control of the primary disease by using a certain induction therapeutic protocol, mobilization of stem cells, collection of mobilized stem cells by apheresis, cryopreservation of the apheresis product, administration of high-dose pretransplant conditioning therapy, and finally infusion of the cryopreserved stem cells after thawing. However, in cancer centers that treat patients with multiple myeloma and have transplantation capabilities but lack or are in the process of acquiring cryopreservation facilities, alternatively noncryopreserved autologous stem cell therapy has been performed with remarkable success as the pretransplant conditioning therapy is usually brief.

Cellular therapies supplement: strategies for improving transplant efficiency in the context of cellular therapeutics

The field of hematopoietic stem cell transplantation (HSCT) has overcome many obstacles that have led to our current clinical ability to utilize cells collected from marrow, mobilized peripheral blood, or umbilical cord blood for the treatment of malignant and nonmalignant hematologic diseases. It is in this context that it becomes evident that future progress will lie in our development of an understanding of the biology by which the process of HSCT is regulated. By understanding the cellular components and the mechanisms by which HSCT is either enhanced or suppressed it will then be possible to design therapeutic strategies to improve rates of engraftment that will have a positive impact on immune reconstitution post-HSCT. In this review we focus primarily on allogeneic hematopoietic stem cell transplantation (allo-HSCT), the current challenges associated with allo-HSCT, and some developing strategies to improve engraftment in this setting.

Current status of stem cell mobilization

New advances in effective mobilization of peripheral blood stem cells have permitted a greater proportion of patients to benefit from autologous stem cell transplantation. In this review, the relative merits of peripheral blood and mobilized bone marrow are discussed. All available agents are reviewed. A critical assessment of the appropriate dosing and frequency of available growth factors is undertaken, and the most commonly used chemotherapy plus growth factor combinations are covered. Specific recommendations for patients who are poor mobilizers are dealt with including the role of plerixafor.

Clinical impact and resource utilization after stem cell mobilization failure in patients with multiple myeloma and lymphoma

High-dose chemotherapy in conjunction with auto-SCT is the preferred treatment of relapsed Hodgkin disease and non-Hodgkin lymphoma and newly diagnosed multiple myeloma. Failure to achieve optimal stem cell mobilization results in multiple subsequent attempts, which consumes large amounts of growth factors and potentially requires antibiotics and transfusions. We retrospectively reviewed the natural history of stem cell mobilization attempts at our institution from 2001 to 2007 to determine the frequency of suboptimal mobilization in patients with hematologic malignancy undergoing autologous transplant and analyzed the subsequent resource utilization in patients with initially failed attempts. Of 1775 patients undergoing mobilization during the study period, stem cell collection (defined by the number of CD34+ cells/kg) was 'optimal' (> or = 5 x 10(6)) in 53%, 'low' (> or = 2-5 x 10(6)) in 25%, 'poor' (<2 x 10(6)) in 10%, and 'failed' (<10 CD34+ cells/microl) in 12%. In the 47% of collections that were less than optimal, increased resource consumption included increased use of growth factors and antibiotics, subsequent chemotherapy mobilization, increased transfusional support, more apheresis procedures, and more frequent hospitalization. This usually unappreciated resource utilization associated with stem cell mobilization failure highlights the need for more effective mobilization strategies.

Pegfilgrastim compared to lenograstim after allogeneic peripheral blood stem-cell transplantation from unrelated donors

We compared a single, subcutaneous fixed dose of 6 mg pegfilgrastim on day +5 with daily lenograstim 263 microg from day +5 and continued until neutrophils were >or=0.5 x 10(9)/L after allogeneic peripheral blood stem-cell transplantation (PBSCT) from unrelated donors for various hematological disorders. Neutrophil engraftment was significantly faster (p = 0.006) in the pegfilgrastim than in the lenograstim group. There was also a tendency towards achieving a faster platelet engraftment (p = 0.06) in the pegfilgrastim group (median 16 vs. 19 days). The duration of thrombocytopenia (<20 x 10(9)/L) was shorter in the pegfilgrastim group (p = 0.05). There were no significant differences in the duration of neutropenia (p = 0.14) and febrile neutropenia (p = 0.25). Differences were not observed in the treatment related mortality, disease free and overall survival between both groups. We conclude that Pegfilgrastim ensured rapid neutrophil engraftment after unrelated allogeneic peripheral SCT, which was at least as effective as daily lenograstim.

Mobilization of peripheral blood stem cells for autologous transplant in non-Hodgkin's lymphoma and multiple myeloma patients by plerixafor and G-CSF and detection of tumor cell mobilization by PCR in multiple myeloma patients

This report describes the first investigational use of plerixafor in Europe and the determination of tumor cell mobilization by polymerase chain-reaction after plerixafor treatment in a subset of patients with multiple myeloma (MM). Thirty-five patients (31 MM and 4 NHL) received granulocyte colony-stimulating factor (G-CSF) (10 microg/kg) each morning for 4 days. Starting the evening of Day 4, patients recieved plerixafor 0.24 mg/kg. Apheresis was initiated 10-11 h later, in the morning of Day 5. This regimen of G-CSF treatment each morning before apheresis and plerixafor treatment in the evening was repeated for up to 5 consecutive days. Mobilization with plerixafor and G-CSF resulted in a median 2.6-fold increase in peripheral blood (PB) CD34+ cell count compared with before plerixafor treatment. All patients collected > or =2 x 10(6) CD34+ cells/kg and 32 of 35 patients collected > or =5 x 10(6) CD34+ cells/kg. After plerixafor treatment, 3 of 7 patients had a small increase and 4 of 7 patients had a small decrease in PB tumor cells. No G-CSF was given post transplant. The median number of days to polymorphonuclear leukocyte and platelet engraftment was 14.0 and 11.0, respectively. There were no reports of graft failure. Plerixafor was generally well tolerated. Mobilization of PB CD34+ cells was consistent with previous clinical trials. The addition of plerixafor did not significantly increase the relative number of PB MM tumor cells.

Single-dose pegfilgrastim is comparable to daily filgrastim in mobilizing peripheral blood stem cells: a case-matched study in patients with lymphoproliferative malignancies.Ann Hematol. 2009;88:673-680. [PMID: 19139894 DOI: 10.1007/s00277-008-0675-5]

Pegfilgrastim (PEGFIL) has been found to be comparable to daily filgrastim (FIL) in managing chemotherapy-induced neutropenia. In the present study, we evaluated the ability of PEGFIL to mobilize stem cells in 38 consecutive patients with lymphoproliferative diseases (multiple myeloma, n = 18; lymphomas, n = 15; chronic lymphocytic leukemia, n = 5). Patients were mobilized using PEGFIL (6-18 mg as a single dose) during 2005-2006; 32 then received high-dose chemotherapy followed by autologous stem cell transplantation. PEGFIL-mobilized patients were matched by age, disease, and treatment line at a ratio of 1:2 to historical FIL-mobilized controls. The primary study endpoint was the blood CD34(+) concentration at onset of leukapheresis. Leukapheresis began a median of 10 days from the beginning of mobilization chemotherapy in both groups. At the onset of leukapheresis, median blood CD34(+) cell counts did not differ significantly in the FIL group compared with the PEGFIL group (79 x 10(6)/L vs 64 x 10(6)/L, respectively; p = 0.44). In the different disease categories, the respective CD34(+) cell counts after FIL and PEGFIL mobilization were 72 x 10(6)/L vs 123 x 10(6)/L (p = 0.08) in myeloma, 51 x 10(6)/L vs 62 x 10(6)/L (p = 0.6) in lymphomas, and 27 x 10(6)/L vs 30 x 10(6)/L (p = 0.62) in CLL, respectively. The target CD34(+) cell yield was harvested with one leukapheresis in 53% of PEGFIL-mobilized patients. Engraftment after autografting did not differ significantly in the two groups. Stem cell mobilization with a single dose of PEGFIL was, therefore, comparable to that achieved using daily FIL in patients with lymphoproliferative diseases. PEGFIL is a more practical way to mobilize stem cells than daily FIL.

Peripheral blood stem cell mobilization: new regimens, new cells, where do we stand. Curr Opin Hematol. 2008;15:285-292. [PMID: 18536564 DOI: 10.1097/moh.0b013e328302f43a]

PURPOSE OF REVIEW

Granulocyte colony-stimulating factor-mobilized peripheral blood stem cells are widely used to reconstitute hematopoiesis; however, preclinical and clinical studies show that improvements to this mobilization can be achieved. We discuss the development of new mobilizing regimens and evaluation of new findings on mobilized stem cell populations that may improve the utility and convenience of peripheral blood stem cell transplant.

RECENT FINDINGS

Chemokines and their receptors regulate leukocyte trafficking, and altering chemokine signaling pathways mobilizes stem cells. In recent trials, combination use of the chemokine (C-X-C motif) receptor 4 antagonist AMD3100 and granulocyte colony-stimulating factor mobilized more CD34 cells in fewer days than granulocyte colony-stimulating factor alone and allowed more patients to proceed to autotransplant. In preclinical studies the chemokine GRObeta synergizes with granulocyte colony-stimulating factor and when used alone or with granulocyte colony-stimulating factor mobilizes more primitive hematopoietic stem cells with less apoptosis, higher integrin activation, lower CD26 expression and enhanced marrow homing compared with granulocyte colony-stimulating factor. Hematopoietic stem cells mobilized by GRObeta or AMD3100 demonstrate superior engraftment and contribution to chimerism in primary and secondary transplant studies in mice, and peripheral blood stem cells mobilized by AMD3100 and granulocyte colony-stimulating factor in patients demonstrate enhanced engraftment capabilities in immunodeficient mice.

SUMMARY

Alternate regimens differentially mobilize stem cell populations with unique intrinsic properties with the potential to expand the utility of hematopoietic transplantation. Continued mechanistic evaluation will be critical to our understanding of mechanisms of mobilization and their use in regenerative medicine.