Comparison of peripheral blood progenitor cell mobilization in patients with multiple myeloma: high-dose cyclophosphamide plus GM-CSF vs G-CSF alone

On-demand plerixafor added to high-dose cyclophosphamide and pegylated recombinant human granulocyte colony-stimulating factor in the mobilization of patients with multiple myeloma: a treatment with high effectiveness, convenient, and affordable cost

Objective

The combination of high-dose cyclophosphamide (HD-Cy) (3g/m2) plus granulocyte colony-stimulating factor (G-CSF) and on-demand plerixafor (PXF) has been considered an effective mobilization regimen of patients with multiple myeloma(MM). However, the daily multi-injection regimen of G-CSF poses challenges. This study delves into the efficiency and cost implications of a novel approach, using HD-Cy alongside pegylated G-CSF (PEG G-CSF) and on-demand PXF. Unlike G-CSF, which necessitates daily injections, the half-life of PEG G-CSF extended allows for a single injection.

Methods

A retrospective analysis was conducted on 350 MM patients, which were categorized based on their mobilization regimens: Cy+PEG G-CSF+/-PXF (n=66), Cy+PEG G-CSF (n=91), Cy+ G-CSF (n=169), and G-CSF+PXF (n=24).

Results

Mobilization with Cy+PEG G-CSF+/-PXF(8.79)yielded a notably higher median CD34+ cell count compared to the other regimens: Cy+PEG G-CSF(4.96), Cy+G-CSF (4.65), and G-CSF+PXF (2.99) (P<0.001). The percentage of patients who achieved >6×106/kg CD34+ cells was significantly higher in the Cy+PEG G-CSF+/-PXF group (77.3%) than in the other mobilization regimens: Cy+PEG G-CSF (41.8%), Cy+ G-CSF (37.3%), and G-CSF+PXF (8.3%) (P<0.001). From a cost perspective, the Cy+PEG G-CSF+/-PXF approach was more economical than the G-CSF+PXF strategy but was marginally costlier than the other two methods. A multivariate assessment highlighted that the combination of Cy+PEG G-CSF with on-demand PXF had a superior potential to achieve the desired harvest (6×106/kg) compared to the Cy+PEG G-CSF protocol without PXF. The incremental cost-effectiveness ratio for each 1% increase in the probability of achieving a successful optimal harvest was $ 97.02 per patient. The incidence of neutropenic fever was 3.0% in the Cy+PEG G-CSF+/-PXF group.

Conclusion

The combination of on-demand PXF with HD-Cy and PEG G-CSF offers a cost-effective approach with a high mobilization success rate, manageable side effects, and the convenience of fewer injections. It stands as a promising mobilization strategy for MM patients.

Pharmacoeconomic issues in stem cell mobilization

BACKGROUND

recently, stem cell mobilization has made dramatic progress, that ended up in an increasing number of aphereses at target for autologous peripheral stem cell transplantation (ASCT). The aim of this research is investigating the cost-effectiveness of stem cell mobilization.

METHODS

a narrative review of the literature was carried out, searching for primary contributions written in English and published during 2000-2023 on cost-effectiveness analysis (CEA) of stem cell mobilization in patients entitled to ASCT. The PubMed database was searched with the following sets of keywords: cost-effectiveness AND apheresis AND myeloma (PubMed_1); cost-effectiveness AND stem cell mobilization (PubMed_2). Articles included in the analysis were assessed via two different checklists.

RESULTS

sixty-six entries were retrieved. Five out of 66 (PubMed_1: 4 out 17; PubMed_2: 1 out of 49), 4 CEAs and 1 cost-utility analysis (CUA) fit the research goal. Four out of 5 contributions proved to be in line with most of the items included in the two assessment grids. However, the most relevant missing features in some of the included contributions were: study perspective, healthcare resources valuation, and sensitivity analyses.

DISCUSSION

most of the articles included in this research show that chemotherapy-free stem cell mobilization is cost-effective according to different standpoints. Future health economic research on this topic should establish local threshold values for incremental apheresis at target and explore the heterogeneity of CEA (and CUA) to determine oncohaematological diseases and patient categories for which chemotherapy-free stem cell mobilization is cost-effective in different healthcare systems, given local budget constraints.

Evaluation of efficacy and safety in the use of cytarabine for mobilization of hematopoietic stem cells in a reference hospital in northeastern Brazil

Autologous hematopoietic stem cell transplantation (Auto-HSCT) is widely used in the treatment of patients with hematological neoplasms. Since these cells circulate in small quantities in the periphery, the use of regimens that promote their mobilization is essential. In this study, we retrospectively evaluated the efficacy and safety of using intermediate doses of cytarabine (1.6 g/m²) + filgrastim (10 mcg/kg/day) in the mobilization of stem cells in 157 patients treated by the Unified Health System at the Hematology and Bone Marrow Transplant Service of the Hospital Real Português de Beneficência, in Recife, Pernambuco. The sample included patients with multiple myeloma (MM) (58.6 %), lymphomas (29.9 %), and other neoplasms (11.5 %). The target of 2.0 × 10 6 CD34+ cells/kg was achieved by 148 (94.3 %) patients, in most cases (84.1 %) in a single apheresis and the median number of cells collected was 9.5 × 10 6 CD34+ cells/kg. No episode of febrile neutropenia was observed, however, 79 patients (50.3 %) required platelet transfusion (no cases attributed to bleeding). The median engraftment time was 11 days. Given these results, we suggest that the use of intermediate doses of cytarabine, combined with filgrastim, is safe and effective in mobilizing hematopoietic stem cells (HSCs).

Non-interventional Study Evaluating the Mobilization of Stem Cells by Plerixafor Before Salvage Autologous Stem Cell Transplant in Relapsed Multiple Myeloma (IFM-2015-03)

INTRODUCTION

Despite the implementation of new therapeutic agents, management of relapsed multiple myeloma (MM) remains a challenge. Salvage autologous hematopoietic cell transplant (AHCT) remains a valid therapeutic option for eligible patients who achieve prolonged response after a first AHCT. However, a second graft is not always available, and these patients may need a second mobilization.

PATIENTS AND METHODS

This prospective, non-interventional, multicenter study aimed to collect data on the feasibility of salvage AHCT using a plerixafor-based hematopoietic cell mobilization in relapsed MM, according to the plerixafor label in France. Adult patients with relapsed MM eligible for a second AHCT and mobilized using granulocyte- colony stimulating factor (G-CSF) and plerixafor were included.

RESULTS

Of the 23 patients, 17 achieved a successful hematopoietic cell mobilization and 13 were able to proceed to a second AHCT. Median age was 62.9 years (min-max 51-71). Ten patients (77%) were male. Eleven (85%) received AHCT as a third-line treatment or more. Median time between first and second AHCT was 5.4 years (range, 2.6-16.3). Among 18 evaluable patients, mobilization was successful for 17 (94%) of them [95% CI 84-100], with no reported side effects. Among the 13 patients who underwent salvage AHCT, the median time to engraftment was 14 days (min-max 11-29). One-year progression-free and overall survival were 88.9% [95% CI 43.3-98.4] and 100%, respectively.

CONCLUSION

This study demonstrated that plerixafor allows safe and efficient mobilization in relapsed MM patients who are candidates for a salvage AHCT.

TRIAL REGISTRATION

NCT02439476 Registered 8 May 2015, https://clinicaltrials.gov/ct2/show/NCT02439476 .

Intermediate-dose cyclophosphamide and bortezomib for PBSC mobilization in multiple myeloma

Although the incorporation of bortezomib into induction regimens has improved, response rates in patients with multiple myeloma (MM), the role of bortezomib in the, peripheral blood stem cell (PBSC) mobilization remains unclear. We assessed the, PBSC mobilization efficacy, safety, and disease response of intermediate-dose, cyclophosphamide and bortezomib in the PBSC mobilization. Twenty-one patients with, newly diagnosed MM were enrolled in a phase II, non-randomized study that used, bortezomib (1.3 mg/m2/day on days 1, 4, 8, and 11) and intermediate-dose, cyclophosphamide (2 g/m2/day on days 2, 3) (Bor-ID-CY). The data from 15 patients, who received intermediate-dose cyclophosphamide (ID-CY) were used as a historical, control group. The total CD34 + cell yield of Bor-ID-CY and ID-CY groups were not, significantly different (median 6.3 ×106/kg vs. 6.5 ×106/kg, p = 0.19). All three patients, with mobilization failure of two groups had t(11;14). Six patients in Bor-ID-CY group, were upgraded from a status that was less than a very good partial response (VGPR), at the time of PBSC mobilization to a VGPR or better after PBSC mobilization, (p = 0.014). Four patients in Bor-ID-CY group developed sepsis. The time to, engraftment was similar in the two groups. The addition of bortezomib to ID-CY did not, impact the stem cell yield or quality.

Stem Cell Mobilization with Ixazomib and G-CSF in Patients with Multiple Myeloma

(1) Background: High-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) is the standard consolidation strategy for patients with newly diagnosed multiple myeloma (MM) and for a subset of patients with relapsed/refractory disease. For stem cell mobilization, G-CSF alone or in combination with chemotherapy mobilizing agents and/or plerixafor are commonly used. Ixazomib is an oral proteasome inhibitor with less neurotoxic potential, which previously showed the ability to mobilize stem cells in preclinical studies. (2) Methods: Prospective single-center phase 1 study assessing the efficacy and safety of stem cell mobilization with ixazomib and G-CSF in patients with newly diagnosed or relapsed/refractory MM undergoing HDCT and ASCT. Primary endpoint was percentage of patients achieving a yield of at least 6.0 × 10⁶/kg CD34+ cells within the first apheresis. G-CSF (filgrastim) 10 μg/kg/day was administered subcutaneously (s.c.) from day 1 to day 5 (planned apheresis) and ixazomib 4 mg orally at day 4. Plerixafor 24 mg s.c. was administered if the stem cell mobilization with ixazomib and G-CSF was not sufficient. (3) Results: 19 patients were treated within the study between 06/2020 and 02/2021. The primary endpoint was reached in 17 (89%) patients, with a median of 7.1 × 10⁶/kg CD34+ cells collected within the first apheresis, comparable to previously published results, and only 2 (11%) patients required a second apheresis. Median number of circulating CD34+ cells was 14.0 × 10⁶/L (2.0-95.2) before the administration of ixazomib, and 33.0 × 10⁶/L (4.2-177.0) pre-apheresis. However, 9 (47%) patients required the addition of plerixafor to ensure optimal stem cell collection. (4) Conclusions: The combination of ixazomib and G-CSF showed promising stem cell mobilizing activity in patients with MM prior to HDCT and ASCT. Future larger studies might further investigate the role of ixazomib in stem cell mobilization regimens for MM.

The association of mobilising regimen on immune reconstitution and survival in myeloma patients treated with bortezomib, cyclophosphamide and dexamethasone induction followed by a melphalan autograft

G-CSF only mobilisation has been shown to enhance immune reconstitution early post-transplant, but its impact on survival remains uncertain. We undertook a retrospective review of 12 transplant centres to examine overall survival (OS) and time to next treatment (TTNT) following melphalan autograft according to mobilisation method (G-CSF only vs. G-CSF and cyclophosphamide [CY]) in myeloma patients uniformly treated with bortezomib, cyclophosphamide and dexamethasone induction. Six centres had a policy to use G-CSF alone and six to use G-CSF + CY. Patients failing G-CSF only mobilisation were excluded. 601 patients were included: 328: G-CSF + CY, 273: G-CSF only. Mobilisation arms were comparable in terms of age, Revised International Staging System (R-ISS) groups and post-transplant maintenance therapy. G-CSF + CY mobilisation generated higher median CD34 + yields (8.6 vs. 5.5 × 10⁶/kg, p < 0.001). G-CSF only mobilisation was associated with a significantly higher lymphocyte count at day 15 post-infusion (p < 0.001). G-CSF only mobilisation was associated with significantly improved OS (aHR = 0.60, 95%CI 0.39-0.92, p = 0.018) and TTNT (aHR = 0.77, 95%CI 0.60-0.97, p = 0.027), when adjusting for R-ISS, disease-response pre-transplant, age and post-transplant maintenance therapy. This survival benefit may reflect selection bias in excluding patients with unsuccessful G-CSF only mobilisation or may be due to enhanced autograft immune cell content and improved early immune reconstitution.

Cyclophosphamide plus etoposide is a safe and effective mobilization regimen in patients with multiple myeloma

High-dose chemotherapy followed by autologous stem cell transplantation is a major component in the treatment of patients with multiple myeloma. As a prerequisite, the successful collection of a sufficient number of viable peripheral blood hematopoietic CD34+ cells is critical. A common standard protocol for mobilization is currently not defined and critically discussed especially in German-speaking Europe. In times of the Covid-19 pandemic, safe and effective strategies have to be chosen to minimize hospitalization times and severe courses. In this single-center retrospective analysis, safety and efficacy of cyclophosphamide plus etoposide (CE) and growth-factor support (n = 33) was compared to cyclophosphamide mono treatment and growth-factor support (n = 49) in 82 patients with multiple myeloma at first diagnosis. CE was superior to cyclophosphamide mono with a significantly higher number of collected CD34+ cells (15.46 × 10⁶ CD34⁺ cells/kg vs. 9.92 × 10⁶ CD34⁺ cells/kg), significantly faster engraftment of granulocytes after stem cell transplantation (day 10.5 vs. day 11.6), shorter duration of the inpatient stay (17.47 days vs. 19.16 days) and significantly less transfusions (8.82 % vs. 30.61 % patients receiving transfusions). The safety profile was comparable in both groups and in line with published data. We conclude that CE is a safe and highly effective mobilization protocol in patients with multiple myeloma at first diagnosis and appears to be superior to the commonly used cyclophosphamide mono regimen.

Filgrastim alone versus cyclophosphamide and filgrastim for mobilization in multiple myeloma patients

BACKGROUND AND OBJECTIVE

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is standard treatment approach in most multiple myeloma (MM) patients. Before ASCT, chemomobilization or only granulocyte-colony stimulating factor (G-CSF) mobilization can be preferred in stem cell mobilization. The primary aim of the study is to compare the effect of the two mobilization regimens on hematopoietic engraftment times, CD34+cell counts and number of apheresis required to harvest stem cells.

MATERIALS AND METHODS

The records of MM patients who applied to our hospital between 2010 and 2020 were analysed retrospectively. Patients were divided into two groups (Group A: Cyclophosphamide plus filgrastim, Group B: Filgrastim alone) according to the mobilization regimen.

RESULTS

A total of 223 MM patients were included in this study (Group A:153, Group B:70 patients). When the patients in Group A and Group B were compared, the number of collected CD34+ cells were higher in Group A (p < 0.001). However, there was no significant difference between the two groups in terms of median times to neutrophil and platelet engraftment, and number of apheresis required to harvest stem cells (p > 0.05). The rate of infection development during mobilization in the patients in group A and the duration of hospitalization of these patients were higher than the patients in group B (p < 0.001). Patients receiving >6 cycles of chemotherapy and immunomodulatory treatment had lower collected CD34+ cells than other patients (p = 0.012 and p = 0.054).

CONCLUSION

Based on our findings, filgrastim alone seems to provide a sufficient amount of stem cells in MM patients.

Chemotherapy-based versus chemotherapy-free stem cell mobilization (± plerixafor) in multiple myeloma patients: an Italian cost-effectiveness analysis

Given the availability and efficacy of the mobilizing agent plerixafor in augmenting hematopoietic progenitor cell mobilization with granulocyte colony-stimulating factor (G-CSF), there is a strong case for comparing the cost-effectiveness of mobilization with G-CSF + cyclophosphamide versus G-CSF alone. This study investigated the cost and effectiveness (i.e., successful 4 million-CD34⁺ collection) of G-CSF alone versus high-dose cyclophosphamide (4 g/m²) + G-CSF mobilization (± on-demand plerixafor) in patients with multiple myeloma (MM) eligible for autograft in Italy. A decision tree-supported cost-effectiveness analysis (CEA) model in MM patients was developed from the societal perspective. The CEA model compared G-CSF alone with cyclophosphamide 4 g/m² + G-CSF (± on-demand plerixafor) and was populated with demographic, healthcare and non-healthcare resource utilization data collected from a questionnaire administered to six Italian oncohematologists. Costs were expressed in Euro (€) 2019. The CEA model showed that G-CSF alone was strongly dominant versus cyclophosphamide + G-CSF ( ± on-demand plerixafor), with incremental savings of €1198.59 and an incremental probability of a successful 4 million-CD34⁺ apheresis (+0.052). Sensitivity analyses confirmed the robustness of the base-case results. In conclusion, chemotherapy-free mobilization (± on-demand plerixafor) is a “good value for money” option for MM patients eligible for autograft.

Low-dose cyclophosphamide and granulocyte colony-stimulating factor are sufficient for peripheral blood stem cell mobilization in patients with multiple myeloma

Autologous stem cell transplantation (ASCT), supported by high-dose chemotherapy, is the prevalent option for multiple myeloma (MM) treatment in candidates suitable for transplantation. Although granulocyte colony-stimulating factor (G-CSF) supported cyclophosphamide (CY) is used as the pre-ASCT mobilization regimen, there is no consensus on the optimal dosage of CY. Thus, in this study, we examined the results of 47 MM patients, who underwent ASCT after mobilization with intermediate (ID) or low-dose (LD) CY treatment supported with G-CSF. As the mobilization regimen, we used ID (2.4 g/m²) of CY in 22 patients, and LD (1 g/m²) of CY in 25 patients. Adequate doses of CD34+ cells were collected in both groups. At the same time, febrile neutropenia was observed to be less common in patients in the LD-CY group. Additionaly 96% of patients in LD-CY group did not need to be hospitalized during the mobilization. In conclusion, we think that mobilization with LD-CY and G-CSF is advantageous since it results in a sufficient amount of stem cells in addition to being advantageous in terms of patient safety and cost.

Cost and efficacy of peripheral stem cell mobilization strategies in multiple myeloma

Mobilization of peripheral blood stem cells (PBSC) can be performed using plerixafor, which is expensive, or high-dose cyclophosphamide (HDCy). We hypothesized that the overall cost of mobilization with plerixafor might not be greater if the cost of complication management was considered. We performed a cost analysis of these two strategies. This multicentric observational study recruited patients with myeloma who underwent a first PBSC mobilization. We considered direct medical costs, including hospitalization, mobilization agents, apheresis, and supportive treatments. We included 111 patients, 54 and 57 in the HDCy and plerixafor groups, respectively. Cost of mobilization with HDCy was 5097 ± 2982€ vs. 10958 ± 1789€ for plerixafor (p < 0.0001). Cost of agents used was 1287 ± 779€ vs. 6552 ± 509€, respectively (p = 0.0009). The mean number of days of hospitalization was 2 and 2.1 days, respectively (p = 0.035). All patients achieved the minimum PBSC collection target (p = 1.0); however, ASCT was performed with HDCy in 67% patients and with plerixafor in 86% (p = 0.02). Plerixafor mobilization incurred a greater cost, mostly due to the greater cost of the drug. Hospitalization length in the two groups was similar in our series. Interestingly, plerixafor appeared to be a very effective and safe mobilizing approach translating into a greater ASCT success.

Higher efficacy of intermediate dose cytarabine + G-CSF compared to cyclophosphamide + G-CSF in hematopoietic stem cell mobilization in patients with multiple myeloma

BACKGROUND

There are several regimens used in hematopoietic stem cell (HSC) mobilization in multiple myeloma (MM). Cyclophosphamide (Cy) is one of the most commonly used agents, although it does not always result in collecting adequate number of CD34+ cells. Recently, cytarabine (Ara-C) has been proposed as potentially efficient and safe option.

AIMS

Since the data regarding Ara-C in HSC mobilization is limited, the aim of our study was to compare retrospectively the efficiency and toxicity of G-CSF combined with either Ara-C or Cy in MM patients.

MATERIALS & METHODS

Of a total of 89 patients, 43 received low or intermediate doses of Cy, and 46 were treated with 800 mg/m² /day of Ara-C administered for two days.

RESULTS

The mean peak of CD34+ cells/ul in peripheral blood was 132 (range, 84-202) in Ara-C and 51 (range, 29-69) in Cy cohort (p < 0.001). The median number of collected CD34+ cells (×106/kg) was 10.3 (range, 4.2-17.9) vs 4.5 (range, 2.7-8.9), respectively (p < 0.001). Mobilization failure was observed in one patient in Ara-C cohort (2%) and in 8 patients treated with Cy (19%) (p = 0.013). In the Ara-C group 98% of patients obtained more than 4×106 CD34+ cells/kg required for tandem transplantation. Moreover, we observed a trend toward increased paraprotein levels measured at transplant compared to before HSC mobilization in Ara-C cohort and significantly higher transfusion rates in that group.

CONCLUSION

Our findings confirm higher HSC mobilization efficacy of Ara-C compared to Cy in MM patients. However, lower transfusions rate and better disease control of Cy may justify its use in some cases.

Outcomes and Cost-Effectiveness of Autologous Hematopoietic Cell Transplant for Multiple Sclerosis

PURPOSE OF REVIEW

This review presents a critical appraisal of the use of autologous hematopoietic cell transplant (AHCT) for the treatment of multiple sclerosis. We present the reader with a brief review on the AHCT procedure, its immunomodulatory mechanism of action in MS, the most recent evidence in support of its use in patients with relapsing-remitting multiple sclerosis (RRMS), as well as its cost considerations.

RECENT FINDINGS

The first meta-analysis of clinical trials of AHCT for patients with MS demonstrated durable 5-year progression-free survival rates and low treatment-related mortality. Recently, the first randomized controlled phase III clinical trial demonstrated AHCT to be superior to best available therapy for a subset of patients with RRMS. This led to the American society for transplant and cellular therapies (ASTCT) to recommend AHCT "for patients with relapsing forms of MS who have prognostic factors that indicate a high risk of future disability." AHCT should be considered for patients with RRMS with evidence of clinical activity who have failed 2 lines of therapy or at least one highly active disease-modifying therapy.

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.

Stem cell mobilization kinetics in elderly patients with multiple myeloma

In this study, we aimed to investigate whether the procedure and product kinetics differ according to age groups in advanced-age MM patients who underwent autologous HSCT. 59 patients who underwent autologous HSCT were retrospectively analyzed. Then, the patients were divided into two groups as 60-65 years and ≥65 years. It was significantly lower in ≥65 years group (p = 0.008) and proportionally, the procedure duration was also significantly shortened in this group (p = 0.013). Total number of collected CD34 positive stem cells was 6.20 × 106 (±3.83) in 60-65 years group while it was 5.51 × 106 (±2.48) in ≥65 years group with no statistically significant difference (p = 0.825). In conclusion, there was no significant difference in terms of the number of collected CD34-positive stem cells in this study that investigates the mobilization data, procedure and product kinetics, we think that successful stem cell mobilization can be performed in appropriately selected patients regardless of age.

Improved progression-free and event-free survival in myeloma patients undergoing PBSCH receiving a cyclophosphamide + G-CSF regimen than G-CSF alone

Two regimens are commonly used for peripheral blood hematopoietic stem cell harvesting (PBSCH) in multiple myeloma: high-dose cyclophosphamide (HD-CY) + granulocyte-colony stimulating factor (G-CSF), and G-CSF alone. The objective of the present study was to evaluate the anti-myeloma effect of the PBSCH regimen including HD-CY. We retrospectively assessed harvesting efficiency, complications, and anti-myeloma effects in 115 patients receiving HD-CY + G-CSF (HD-CY group) and 32 patients receiving G-CSF alone (G-alone group). We collected > 2 × 10⁶ CD34-positive cells/kg from 93 and 75% of patients in the HD-CY and G-alone groups, respectively (P = 0.0079). The mean HSC count was also higher in the HD-CY group. No severe complications were observed in the G-alone group, whereas 66% of patients in the HD-CY group were treated with intravenous antibiotics. The median progression-free and event-free survival (PFS and EFS) were longer in the HD-CY group than in the G-alone group (28 vs. 18 months and 25 vs. 13 months, respectively; P = 0.0127 and 0.0139), with no difference in median overall survival. HD-CY showed anti-myeloma effect, as verified by prolonged EFS and PFS, when a vincristine, doxorubicin, and dexamethasone regimen was administered as induction before PBSCH.

Mobilization of Hematopoietic Progenitor Cells with Standard- or Reduced-Dose Filgrastim after Vinorelbine in Multiple Myeloma Patients: A Randomized Prospective Single-Center Phase II Study

Vinorelbine combined with filgrastim at a dose of 10 µg/kg of body weight (BW) per day is a reliable and well-tolerated regimen for mobilization of hematopoietic progenitor cells (HPCs) in patients with multiple myeloma. This prospective, randomized, phase II study was initiated to assess the feasibility of a reduced filgrastim dosage. Vinorelbine was combined with either standard-dose filgrastim (10 µg/kg BW per day) or reduced-dose filgrastim (5 µg/kg BW per day). Leukapheresis sessions were planned to start at day 8 and were continued until the predefined target amount of 4 × 10⁶ HPCs/kg BW was collected. The study demonstrated the feasibility of vinorelbine combined with reduced daily filgrastim with a mean of 1.29 leukapheresis sessions necessary per patient (95% confidence interval, .95 to 1.7). All patients could start leukapheresis as planned at day 8, and the collection success rate was 100% for the whole patient collective after a maximum of 2 leukapheresis sessions. No statistically significant differences with regard to the amount of HPCs collected between the 2 groups were observed (P = .99). Accordingly, no differences were seen with regard to length of hospitalization for autotransplant (P = .34) and duration of neutrophil (P = .93) and platelet engraftment (P = .42). Patients receiving reduced-dose filgrastim reported significantly lower peak pain values in a numeric analogue scale (P = .01), and the costs were significantly lower than in patients undergoing standard-dose chemomobilization (P = .001). Vinorelbine 35 mg/m² plus filgrastim 5 µg/kg BW once per day until completion of HPC collection is feasible and appears to be advantageous with respect to the severity of pain intensity and treatment costs.

Peripheral blood stem cell mobilization in multiple myeloma: Growth factors or chemotherapy?

High-dose therapy followed by autologous hematopoietic stem cell (HSC) transplant is considered standard of care for eligible patients with multiple myeloma. The optimal collection strategy should be effective in procuring sufficient HSC while maintaining a low toxicity profile. Currently available mobilization strategies include growth factors alone, growth factors in combination with chemotherapy, or growth factors in combination with chemokine receptor antagonists; however, the optimal strategy has yet to be elucidated. Herein, we review the risks and benefits of each approach.

Stem Cell Transplantation for Multiple Myeloma

BACKGROUND

Multiple myeloma (MM) is the second most common hematologic malignancy, affecting approximately 14,000 new patients in the United State per year. The median overall survival is 5 years, and cure is a realistic goal for only a small minority of patients.

METHODS

A review of the literature was conducted that focused on treatment strategies for MM involving administration of high doses of chemotherapy followed by autologous or allogeneic hematopoietic stem cell transplant.

RESULTS

For over three decades, the standard treatment for MM has been a regimen of melphalan and prednisone (MP). Complete responses (CRs) have been rare, and 50% of patients have had disease that was resistant to treatment with MP. Attempts have been made to improve the outcome of MM by administering other combinations of standard doses of chemotherapy, but these treatments are equivalent in terms of overall survival. For patients who are candidates, high-dose therapy followed by autologous stem cell transplantation results in higher CR rates and improved long-term survival compared to treatment with standard doses of chemotherapy alone. While this strategy represents an advance in the treatment of MM, evidence-based reviews indicate that there are a number of issues to consider regarding the induction therapy, the collection of stem cells, and the timing, type, and number of high-dose therapies to use in this type of treatment strategy.

CONCLUSIONS

Advances have been made in autologous transplantation, allogeneic transplantation, anti-MM agents, and immunotherapy for MM. Combining these different strategies to achieve synergistic responses is an exciting possibility.

Cyclophosphamide-based stem cell mobilization in relapsed multiple myeloma patients: A subgroup analysis from the phase III trial ReLApsE

OBJECTIVE

Analysis of the efficiency and toxicity of cyclophosphamide-based stem cell mobilization in patients with relapsed multiple myeloma (RMM).

METHODS

Peripheral blood stem cells (PBSCs) were mobilized with high dose cyclophosphamide (2 g/m² daily on days 1 and 2) and G-CSF plus pre-emptive/rescue plerixafor in RMM patients (first to third relapse) treated within the ReLApsE trial of the German-Speaking Myeloma Multicenter Group (GMMG).

RESULTS

Mobilization was initiated with high-dose cyclophosphamide (HD-CY) and G-CSF in 30 patients. Fifteen patients received additional pre-emptive/rescue administration of plerixafor. Stem cell collection was successful (≥2×10⁶ CD34+ cells per kg bw) in 77% (23/30 patients). Patients with prior high-dose melphalan collected a significantly lower median total number of PBSCs than patients without prior high-dose melphalan (3.3×10⁶ vs 17×10⁶ CD34+ cells/kg bw). Toxicity of HD-CY was frequent with 12 serious adverse events (SAE) in 37% of patients (11/30 patients). Infections accounted for the majority of SAE reports. In two patients, SAEs were lethal (septic shock).

CONCLUSIONS

These data proof feasibility of PBSC collection at relapse but emphasize the importance of collection and storage of additional PBSC transplants during first-line treatment when mobilization is more efficient and less toxic.

Single Dose Preemptive Plerixafor for Stem Cell Mobilization for ASCT After Lenalidomide Based Therapy in Multiple Myeloma: Impact in Resource Limited Setting

Peripheral blood stem cell mobilization with cytokines for autologous stem cell transplant in multiple myeloma is adversely affected by initial induction therapy consisting of either Lenalidomide or cytotoxic drugs, with failure rates of up to 45%. The use of Plerixafor with G-CSF for PBSC mobilisation significantly improves the chances of a successful mobilization. Plerixafor is a costly therapy and increases the overall costs of ASCT which can affect the number of patients being taken up for ASCT in resource limited settings. We prospectively studied the impact of single dose preemptive Plerixafor for PBSC mobilization in patients with prior Lenalidomide exposure. 26 patients who had received Lenalidomide based induction protocol underwent PBSC mobilisation during the study period with G-CSF 10 μg/kg/day SC for 4 days and single dose preemptive Plerixafor 240 μg/kg SC stat 11 h before the scheduled PB stem cell harvest on D5, based on a D4 PB CD34+ counts of <20/μL. A median of 07 cycles of Lenalidomide based combination therapy was used for induction therapy prior to ASCT. 84% patients underwent successful mobilization with one sitting of stem cell harvest post a single dose of Inj Plerixafor. 7.6% patients failed to mobilise the predefined minimum cell dose of CD34 and could not be taken up for ASCT. The median CD34% of the harvest bag sample was 0.33% (0.1-0.97%). Injection site erythema (34%), paresthesia's (34%) and nausea (30%) were the commonest adverse events reported post Inj Plerixafor. We did a real-world cost analysis for a resource limited setting for PBSC mobilization and found significant cost savings for the preemptive Plerixafor group.

Modified CVAD and modified CBAD compared to high-dose cyclophosphamide for peripheral blood stem cell mobilization in patients with multiple myeloma

BACKGROUND

The optimal regimen for peripheral blood stem cell (PBSC) mobilization in patients with multiple myeloma undergoing autologous hematopoietic stem cell transplantation (auto-HCT) has not been established. Experience at The University of Texas MD Anderson Cancer Center suggests in addition to single-agent cyclophosphamide (Cy), modified cyclophosphamide, vincristine, doxorubicin, and dexamethasone (mCVAD), and modified cyclophosphamide, bortezomib, doxorubicin, and dexamethasone (mCBAD) may be successful chemomobilization regimens.

METHODS

This retrospective review included 167 patients (66 with Cy, 74 with mCVAD, and 27 with mCBAD) with multiple myeloma undergoing mobilization for auto-HCT between January 1, 2006 and September 30, 2013. The primary objective was to evaluate and compare the successful mobilization of CD34+ cells among high-dose Cy, mCVAD or mCBAD.

RESULTS

Successful mobilization (≥2×10⁶ CD34+ cells/kg) was achieved in all patients, while 65 (98%), 72 (97%), and 27 (100%) patients achieved an optimal mobilization (≥4×10⁶ CD34+ cells/kg) in the Cy, mCVAD, and mCBAD groups, respectively. There was no significant difference in the number of apheresis sessions (P=.63), incidence of febrile neutropenia (P=.57), or hospital admission rates (P=.55).

CONCLUSION

Either Cy, mCVAD, or mCBAD can yield successful PBSC mobilization in patients with multiple myeloma undergoing auto-HCT.

How to manage poor mobilizers for high dose chemotherapy and autologous stem cell transplantation?

Today, peripheral blood stem cells are the preferred source of stem cells over bone marrow. Therefore, mobilization plays a crutial role in successful autologous stem cell transplantation. Poor mobilization is generally defined as failure to achieve the target level of at least 2×10⁶ CD34⁺ cells/kg body weight. There are several strategies to overcome poor mobilization: 1) Larger volume Leukapheresis (LVL) 2) Re-mobilization 3) Plerixafor 4) CM+Plerixafor (P)+G-CSF and 5) Bone Marrow Harvest. In this review, the definitions of successful and poor mobilization are discussed. Management strategies for poor mobilization are defined. The recent research on new agents are included.

Upfront use of plerixafor and granulocyte-colony stimulating factor (GCSF) for stem cell mobilization in patients with multiple myeloma: efficacy and analysis of risk factors associated with poor stem cell collection efficiency

Plerixafor (P), an agent that selectively and reversibly binds to the chemokine receptor CXCR4, has been approved in combination with G-CSF (P + G-CSF) for stem cell (SC) mobilization in patients with multiple myeloma (MM). The goal of this study was to determine the SC collection success rate of P + G-CSF using a clinically relevant outcome defined as the ability to collect at least 5 × 10⁶ CD34⁺ cells/kg to allow safely two transplants, and identify risk factors impacting SC mobilization. One hundred and thirty-eight patients were mobilized with P + G-CSF upfront following induction. The SC collection success rate was 92.8%. We identified exposure to lenalidomide alone (p = .038), WBC count <4 × 10³/mcL prior to mobilization (p = .01) and non-African American race (p = .019), as risk factors for low efficiency by multivariate analysis. This study demonstrates that P + G-CSF is highly efficient in MM patients and provides strong support for its upfront use in SC collection for MM patients.

Combined plerixafor and granulocyte colony-stimulating factor for harvesting high-dose hematopoietic stem cells: Possible niche for plerixafor use in pediatric patients

PB is a source of HSC, especially for autologous HCT in solid tumors. However, there is a risk of failing to achieve the target number of SC after mobilization with growth factors alone in patients who were heavily pretreated with chemotherapy or those in need for tandem transplants. SC were harvested from seven pediatric patients with solid tumors who were in need of autologous HCT following combination GCSF and plerixafor. Six of them received plerixafor after failing to achieve enough SC with GCSF only, while the seventh patient received the combined protocol upfront. All seven patients achieved the target number of SC according to their treatment protocol. There were no adverse events. All patients underwent autologous HCT using the harvested HSC and achieved full engraftment. A protocol for harvesting autologous HCT using GCSF and plerixafor is feasible and safe in children with solid tumors who had been heavily pretreated with chemotherapy or needed tandem transplants.

The High Effect of Chemomobilization with High-Dose Etopside + Granulocyte-Colony Stimulating Factor in Autologous Hematopoietic Peripheral Blood Stem Cell Transplantation: A Single Center Experience

Autologous hematopoietic stem cell transplantation (auto-HSCT) provides hematopoietic support after high-dose chemotherapy and is the standard of care for patients with multiple myeloma (MM), chemo sensitive relapsed high or intermediate grade non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). However, yields of hematopoietic stem cells vary greatly between patients, and the optimal strategy to mobilize hematopoietic stem cells into peripheral blood for collection has not been defined yet. We investigated the efficacy and safety of chemo mobilization with an intermediate dose etoposide (VP-16; 200 mg/m² on days 1-3) and granulocyte-colony stimulating factor (G-CSF)(5 µg/kg twice daily from day 4 through the final day of collection). We reviewed our institutional experience with 91 patients (71 MM, 12 HL, 8 NHL) mobilized with this regimen. VP-16 + G-CSF resulted in successful mobilization in 95.55% of the patients (on one patient stem cell collection with plerixafor was applied), including 76 patients (83.52%) whose stem cells were collected successfully in a single day. Collection was managed between min. D8 and max. D17. Patient age, gender, exposure to previous irradiation and chemotherapy, previous mobilization attempts, and disease characteristics were not considered during selection. Adverse effects of the regimen included supportive transfusions and fevers requiring hospitalization or intravenous antibiotics. VP-16 and G-CSF appears to be a safe and effective mobilization regimen for patients with multiple myeloma, non-Hodgkin’s lymphoma and Hodgkin’s lymphoma undergoing autologous stem cell transplantation, producing excellent stem cell yield with the majority of patients requiring 1 day of apheresis.

Cyclophosphamide plus granulocyte-colony stimulating factor for hematopoietic stem cell mobilization in patients with multiple myeloma

We retrospectively reviewed the results of cyclophosphamide (3 g/m(2) ), doxorubicin and dexamethasone plus granulocyte-colony stimulating factor (G-CSF) (ID-CY/DOX group), low-dose cyclophosphamide (2 g/m(2) ) plus G-CSF (LD-CY group) and G-CSF alone (G-CSF group) for stem cell mobilization in patients with multiple myeloma. A total of 89 patients with 93 mobilizations were included. Apheresis was started when total white blood cell (WBC) count >10 × 10(9) /L for ID-CY/DOX and LD-CY groups and after eight doses of G-CSF (5 μg/kg twice daily) for G-CSF group. For five mobilizations in ID-CY/DOX group, the rate of successful mobilization (≥4.0 × 10(6) /kg CD34+ cells) was 80%. For 78 mobilizations in LD-CY group, the successful rate was 80.8%. For 10 mobilizations in the G-CSF group, the successful rate was 50%. The mean yield of CD34+ cells was higher in ID-CY/DOX and LD-CY groups as compared with that in G-CSF group (P = 0.026 and 0.020, respectively). There was no difference in the yield of CD34+ cells between ID-CY/DOX and LD-CY groups (P = 0.831). After autologous stem cell transplantation, the days to neutrophil and platelet engraftment were similar in these three groups (P = 0.713 and 0.821, respectively). In conclusion, we observed that ID-CY/DOX and LD-CY plus G-CSF for stem cell mobilization resulted in a higher successful rate and higher stem cell yields than G-CSF alone and their engraftment time were similar. Total WBC count >10 × 10(9) /L can be used as a guide to start apheresis in CY-based stem cell mobilization. J. Clin. Apheresis 31:423-428, 2016. © 2015 Wiley Periodicals, Inc.

Contribution of chemotherapy mobilization to disease control in multiple myeloma treated with autologous hematopoietic cell transplantation

In patients with multiple myeloma (MM) undergoing autologous hematopoietic cell transplantation (auto-HCT), peripheral blood progenitor cells (PBPCs) may be collected following mobilization with growth factor alone (GF) or cytotoxic chemotherapy plus GF ( (CC+GF). It is uncertain whether the method of mobilization affects post-transplant outcomes. We compared these mobilization strategies in a retrospective analysis of 968 patients with MM from the Center for International Blood and Marrow Transplant Research database who received an auto-HCT in the US and Canada between 2007 and 2012. The kinetics of neutrophil engraftment (≥ 0.5 × 10⁹/L) was similar between groups (13 vs. 13 days, P=0.69) while platelet engraftment (≥ 20 × 10⁹/L) was slightly faster with CC+GF (19 vs. 18 days, P=0.006). Adjusted 3-years PFS was 43% (95% C.I. 38–48) in GF and 40% (95% C.I. 35–45) in CC+GF, P=0.33. Adjusted 3-years OS was 82% (95% C.I. 78–86) vs. 80% (95% C.I. 75–84), P=0.43 and adjusted 5-year OS was 62% (95C.I. 54–68) vs. 60% (95% C.I. 52–67), P=0.76, for GF and CC+GF respectively. We conclude that MM patients undergoing auto-HCT have similar outcomes irrespective of the method of mobilization and found no evidence that the addition of chemotherapy to mobilization contributes to disease control.

Hematopoietic progenitor cell mobilization for autologous transplantation - a literature review

The use of high-dose chemotherapy with autologous support of hematopoietic progenitor cells is an effective strategy to treat various hematologic neoplasms, such as non-Hodgkin lymphomas and multiple myeloma. Mobilized peripheral blood progenitor cells are the main source of support for autologous transplants, and collection of an adequate number of hematopoietic progenitor cells is a critical step in the autologous transplant procedure. Traditional strategies, based on the use of growth factors with or without chemotherapy, have limitations even when remobilizations are performed. Granulocyte colony-stimulating factor is the most widely used agent for progenitor cell mobilization. The association of plerixafor, a C-X-C Chemokine receptor type 4 (CXCR4) inhibitor, to granulocyte colony stimulating factor generates rapid mobilization of hematopoietic progenitor cells. A literature review was performed of randomized studies comparing different mobilization schemes in the treatment of multiple myeloma and lymphomas to analyze their limitations and effectiveness in hematopoietic progenitor cell mobilization for autologous transplant. This analysis showed that the addition of plerixafor to granulocyte colony stimulating factor is well tolerated and results in a greater proportion of patients with non-Hodgkin lymphomas or multiple myeloma reaching optimal CD34⁺ cell collections with a smaller number of apheresis compared the use of granulocyte colony stimulating factor alone.

G-CSF plus preemptive plerixafor vs hyperfractionated CY plus G-CSF for autologous stem cell mobilization in multiple myeloma: effectiveness, safety and cost analysis

The optimal stem cell mobilization regimen for patients with multiple myeloma (MM) remains undefined. We retrospectively compared our experience in hematopoietic cell mobilization in 83 MM patients using fractionated high-dose CY and G-CSF with G-CSF plus preemptive plerixafor. All patients in the CY group (n=56) received fractionated high-dose CY (5 g/m(2) divided into five doses of 1 g/m(2) every 3 h) with G-CSF. All patients in the plerixafor group (n=27) received G-CSF and plerixafor preemptively based on an established algorithm. Compared with plerixafor, CY use was associated with higher total CD34+ cell yield (7.5 × 10(6) vs 15.5 × 10(6) cells/kg, P=0.005). All patients in both groups yielded ⩾4 × 10(6) CD34+ cells/kg. Conversely, CY use was associated with high frequency of febrile neutropenia, blood and platelet transfusions need and hospitalizations. The average total cost of mobilization in Lebanon was slightly higher in the plerixafor group ($7886 vs $7536; P=0.16). Our data indicate robust stem cell mobilization in MM patients with either fractionated high-dose CY and G-CSF or G-CSF alone with preemptive plerixafor. The chemo-mobilization approach was associated with twofold stem cell yield, slightly lower cost but significantly increased toxicity.

Cyclophosphamide-based hematopoietic stem cell mobilization before autologous stem cell transplantation in newly diagnosed multiple myeloma

High-dose cyclophosphamide (Cy) is frequently employed for peripheral blood mobilization of hematopoietic stem cells before high-dose chemotherapy with autologous stem cell transplantation (ASCT) in multiple myeloma (MM). The benefit of mobilization with Cy over filgrastim (granulocyte colony-stimulating factor; G-CSF) alone is unclear. Between 2000 and 2008, 167 patients with newly diagnosed MM underwent single ASCT after melphalan conditioning at our institution. Seventy-three patients were mobilized with G-CSF alone, and 94 patients with Cy plus G-CSF (Cy+G-CSF). We retrospectively analyzed Cy's impact on both toxicity and efficacy. Mobilization efficiency was augmented by Cy; a mean total of 12 versus 5.8 × 10(6) CD34+ cells/kg were collected from patients mobilized with Cy+G-CSF versus G-CSF, respectively, (P < 0.01), over a mean of 1.6 versus 2.2 days of peripheral blood apheresis (p = 0.001). Mobilization-related toxicity was also, however, augmented by Cy; 14% of Cy+G-CSF patients were hospitalized because of complications versus none receiving G-CSF (P < 0.0001). Toxicity, including death, related to ASCT was similar between cohorts. Regarding long-term outcomes, multivariate analysis revealed no difference for Cy+G-CSF versus G-CSF (hazard ratio 0.8 for event-free survival [95% confidence interval {CI} 0.57-1.25] and 0.96 for overall survival [95% CI 0.61-1.54]). In summary, we show that mobilization with Cy increases toxicity without positively impacting long-term outcomes in MM. Our findings place into question Cy's benefit as a routine component of stem cell mobilization regimens in MM. Randomized trials are needed to elucidate the risks and benefits of Cy more definitively.

Efficacy of vinorelbine plus granulocyte colony-stimulation factor for CD34+ hematopoietic progenitor cell mobilization in patients with multiple myeloma

We aimed to assess the efficacy of vinorelbine plus granulocyte colony-stimulating factor (G-CSF) for chemo-mobilization of CD34(+) hematopoietic progenitor cells (HPC) in patients with multiple myeloma and to identify adverse risk factors for successful mobilization. Vinorelbine 35 mg/m(2) was administered intravenously on day 1 in an outpatient setting. Filgrastim 5 μg/kg body weight (BW) was given twice daily subcutaneously from day 4 until the end of the collection procedure. Leukapheresis was scheduled to start on day 8 and be performed for a maximum of 3 consecutive days until at least 4 × 10(6) CD34(+) cells per kg BW were collected. Overall, 223 patients were mobilized and 221 (99%) patients proceeded to leukapheresis. Three (1.5%) patients required an unscheduled hospitalization after chemo-mobilization because of neutropenic fever and renal failure (n = 1), severe bone pain (n = 1), and abdominal pain with constipation (n = 1). In 211 (95%) patients, the leukaphereses were started as planned at day 8, whereas in 8 (3%) patients the procedure was postponed to day 9 and in 2 (1%) patients to day 10. In the great majority of patients (77%), the predefined amount of HPC could be collected with 1 leukapheresis. Forty-four (20%) patients needed a second leukapheresis, whereas only 6 (3%) patients required a third leukapheresis procedure. The median number of CD34(+) cells collected was 6.56 × 10(6) (range, .18 to 25.9 × 10(6)) per kg BW at the first day of leukapheresis and 7.65 × 10(6) (range, .18 to 25.9 × 10(6)) per kg BW in total. HPC collection was successful in 212 (95%) patients after a maximum of 3 leukaphereses. Patient age (P = .02) and prior exposition to lenalidomide (P < .001) were independent risk factors for a lower HPC amount collected in multiple regression analysis. Vinorelbine plus G-CSF enables a very reliable prediction of the timing of leukapheresis and results in successful HPC collection in 95% of the patients.

New insights in the mobilization of hematopoietic stem cells in lymphoma and multiple myeloma patients

Following chemotherapy and/or the administration of growth factors, such as granulocyte-colony stimulated factor (G-CSF), hematopoietic stem cells (HSC) mobilize from bone marrow to peripheral blood. This review aims to systematically present the structure of the HSC "niche" and elucidate the mechanisms of their mobilization. However, this field is constantly evolving and new pathways and molecules have been shown to contribute to the mobilization process. Understanding the importance and the possible primary pathophysiologic role of each pathway is rather difficult, since they share various overlapping components. The primary initiating event for the mobilization of HSC is chemotherapy-induced endogenous G-CSF production or exogenous G-CSF administration. G-CSF induces proliferation and expansion of the myelomonocytic series, which leads to proteolytic enzyme activation. These enzymes result in disruption of various receptor-ligand bonds, which leads to the disanchorage of HSC from the bone marrow stroma. In everyday clinical practice, CXC chemokine receptor-4 (CXCR4) antagonists are now being used as mobilization agents in order to improve HSC collection. Furthermore, based on the proposed mechanisms of HSC mobilization, novel mobilizing agents have been developed and are currently evaluated in preclinical and clinical studies.

Autologous haematopoietic stem cell mobilisation in multiple myeloma and lymphoma patients: a position statement from the European Group for Blood and Marrow Transplantation

Autologous haematopoietic SCT with PBSCs is regularly used to restore BM function in patients with multiple myeloma or lymphoma after myeloablative chemotherapy. Twenty-eight experts from the European Group for Blood and Marrow Transplantation developed a position statement on the best approaches to mobilising PBSCs and on possibilities of optimising graft yields in patients who mobilise poorly. Choosing the appropriate mobilisation regimen, based on patients' disease stage and condition, and optimising the apheresis protocol can improve mobilisation outcomes. Several factors may influence mobilisation outcomes, including older age, a more advanced disease stage, the type of prior chemotherapy (e.g., fludarabine or melphalan), prior irradiation or a higher number of prior treatment lines. The most robust predictive factor for poor PBSC collection is the CD34(+) cell count in PB before apheresis. Determination of the CD34(+) cell count in PB before apheresis helps to identify patients at risk of poor PBSC collection and allows pre-emptive intervention to rescue mobilisation in these patients. Such a proactive approach might help to overcome deficiencies in stem cell mobilisation and offers a rationale for the use of novel mobilisation agents.

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.

Hematopoietic progenitor cell mobilization using low-dose cyclophosphamide and granulocyte colony-stimulating factor for multiple myeloma

High-dose chemotherapy (HDT) supported by autologous stem cell transplantation (ASCT) has long been one of the standards of care for younger patients with multiple myeloma (MM). Cyclophosphamide (CY) plus granulocyte colony-stimulating factor (G-CSF) has been the conventional preparation for hematopoietic progenitor cell (HPC) mobilization, although the optimal dosage of CY in this setting has not yet been clearly defined. This study investigated the efficacy and safety of low-dose (LD-)CY (1.5 g/m(2)) plus G-CSF for conditioning for HPC apheresis harvest (HPC-A) in 18 MM patients, and compared it with a regimen consisting of intermediate-dose (ID)-CY (4 g/m(2)) plus G-CSF for 13 MM patients. Eleven patients in the former and six in the latter were treated with bortezomib (BTZ) during the induction therapy. Both regimens were comparably effective in terms of CD34(+) cell yields, while adverse events, such as leukopenia, thrombocytopenia, and febrile neutropenia, occurred significantly less frequently in the LD-CY cohort. All patients in LD-CY cohort started and completed their apheresis on day 7 or 8, whereas for the ID-CY cohort the day of first apheresis varied widely from day 8 to 15. These findings indicate that the LD-CY regimen is as effective as ID-CY for HPC mobilization, while the former is clearly more practicable and convenient than the ID-CY regimen for patients with MM.