A comparison of toxicity following two different doses of cyclophosphamide for mobilization of peripheral blood progenitor cells in 116 multiple myeloma patients

Efficacy of prophylactic antibiotics for the prevention of neutropenic fever in patients with multiple myeloma receiving high-dose cyclophosphamide for stem cell mobilization

High-dose cyclophosphamide (HD-Cy) (3 g/m2) plus granulocyte colony-stimulating factor (G-CSF) is a very effective regimen for peripheral blood stem cell (PBSC) mobilization. Unfortunately, it is associated with an increased risk of neutropenic fever (NF). We analyzed the effect of NF on PBSC apheresis results and the efficacy of prophylactic antibiotics for the prevention of NF associated with HD-Cy plus G-CSF for PBSC mobilization in patients with newly diagnosed multiple myeloma (MM). First, patients were divided into NF ( +) and NF ( -) groups according to whether they suffered from NF during mobilization. Second, we divided patients into an antibiotic prophylaxis group and a nonantibiotic prophylaxis group according to whether antibiotic prophylaxis was used during the mobilization period. Our study showed that NF( +) patients (n = 44) had lower CD34 + cell dose collection (median 2.60 versus 5.34 × 106/kg, P < 0.001) and slower neutrophil engraftment and platelet engraftment (median 11 versus 10 days, P = 0.002, and median 13 versus 11 days, P = 0.043, respectively) than NF( -) patients (n = 234). Of note, the nonantibiotic prophylaxis group patients (n = 30) had a 26.7% incidence of NF. In the patients receiving antibiotic prophylaxis (n = 227), the incidence was reduced to 9.3% (P = 0.01). The antibiotic prophylaxis patients had higher CD34 + cell collection (median 5.41 versus 2.27 × 106/kg, P < 0.001) and lower hospitalization cost of mobilization ($ median 3108.02 versus 3702.39, p = 0.012). Thus, our results demonstrate that NF is associated with lower CD34 + cell collection and that antibiotic prophylaxis can reduce the incidence of NF and improve stem cell mobilization and collection outcomes, which reduces the hospitalization cost of mobilization.

Prolonged infusion time of cyclophosphamide plus granulocyte colony-stimulating factor (G-CSF) as a mobilization regimen may improve mobilization efficiency in newly diagnosed multiple myeloma patients: a single center experience

OBJECTIVES

This study aimed to clarify the effectiveness and safety of two different infusion durations of cyclophosphamide (CTX) plus granulocyte colony-stimulating factor (G-CSF) for peripheral blood stem cell mobilization in patients with newly diagnosed multiple myeloma (NDMM).

METHODS

One hundred and fifty-six consecutive NDMM patients receiving CTX plus G-CSF mobilization and autologous stem cell transplantation during the period of September 2008 to May 2020 were selected for retrospective analysis. According to differences in prolonged infusion time of CTX, they were divided into a 24-h group (24-h continuous infusion) and a control group (4-6 h of infusion). Mobilization and safety of infusion were analyzed. Flow cytometry was used to detect the peripheral blood CD34+ cell count. Multivariate analysis was performed to determine the factors influencing the number of CD34+ cells.

RESULTS

The mean CD34+ cell counts collected in 24-h and control groups were 6.78 (interquartile range [IQR] 3.59-11.69) and 4.48 (IQR 2.39-6.30) ×106/kg, respectively (p < 0.001). Meanwhile, the target number of CD34+ cells/kg (defined as ≥4 × 106/kg) was collected from 51 (75%) of cases in 24-h group vs. 45 (51%) in the control group (p = 0.002). Multivariate analysis identified the independence of CTX infusion time as a factor influencing the target number of CD34+ cells/kg [odds ratio OR, 4.045; 95% CI: 1.630-10.038, p = 0.003]. The post-transplantation time to neutrophil engraftment was 10 (IQR 9-11) in 24-h group and 11 (IQR 10-12) in control group (p < 0.001). Finally, no statistical differences were identified between groups in terms of hematologic and non-hematologic toxicities.

CONCLUSIONS

For patients with NDMM, 24-h continuous infusion of CTX plus G-CSF contributes to improved mobilization efficiency and equivalent toxicity as a stem cell mobilization regimen.

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.

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.

Are we choosing mobilization regimens for autologous stem cell transplantation in multiple myeloma wisely: A single center comparison of GCSF+/-plerixafor vs cyclophosphamide/GCSF+/-plerixafor

BACKGROUND

Autologous stem cell transplantation (ASCT) is a standard consolidation treatment for eligible patients with multiple myeloma (MM). There is no standardized mobilization regimen for collection of CD34+ stem cells, which is crucial to the success of ASCT. Cyclophosphamide/GCSF is an effective regimen, although reported associated toxicities include risk of febrile neutropenia (FN). Since plerixafor was introduced in Canada, this mobilization agent has been increasingly used as needed with GCSF at Kingston Health Science Centre (KHSC), with elimination of cyclophosphamide. This single center, retrospective, quality improvement study evaluates mobilization and ASCT outcomes of MM patients who had undergone stem cell mobilization at KHSC with cyclophosphamide/GCSF+/-plerixafor without antibiotics, cyclophosphamide/GCSF+/-plerixafor with antibiotics, and GCSF+/-plerixafor without antibiotics.

METHODS

A retrospective chart review was conducted evaluating 137 patients. The primary outcome measure was FN rates with mobilization. Balancing measures include CD34+ cell collected, plerixafor usage, days of apheresis and transplant outcomes. Chi-square, ANOVA, or Kruskal-Wallis methods were used to test statistical significance where appropriate.

RESULTS

Our study noted a higher total and day one CD34+ count in the two groups utilizing cyclophosphamide in mobilization. All nine cases of FN occurred in these two groups (P < .05). Addition of antibiotics decreased, but did not eliminate risk of FN. There were no significant differences in the rate of plerixafor usage and number of apheresis days. Difference in transplant outcomes, including engraftment and transfusion support, were statistically but not clinically significant. A larger sample size may be needed to explore this fully. There was no significant difference in length of transplant hospital stay.

CONCLUSION

The elimination of cyclophosphamide from mobilization regimens for MM appears to significantly reduce FN rates, without increasing balancing measures such as total number of apheresis days, plerixafor usage, duration of transplant hospitalization or mortality outcomes.

Safety of outpatient stem cell mobilization with low- or intermediate-dose cyclophosphamide in newly diagnosed multiple myeloma patients

OBJECTIVES

Autologous stem cell transplantation is the gold standard for eligible newly diagnosed multiple myeloma patients. Patients are usually hospitalized for administration of mobilization chemotherapy. We aimed to assess safety and efficacy of mobilization therapy with low-dose (2 g/m² ) and intermediate-dose (3-4 g/m² ) cyclophosphamide administered as outpatient.

METHODS

A total of 176 consecutive newly diagnosed transplant-eligible myeloma patients receiving outpatient mobilization were retrospectively evaluated. Induction therapy was mainly performed with new drugs (91%).

RESULTS

Chemotherapy was very well tolerated with 16.6% of patients having all-grade adverse events (AEs) and only 1.2% having severe AEs. The most frequently reported AEs were nausea and vomiting grade 1-2 (6.8%). Only 5.7% of patients required hospitalization for AEs. Stem cell collection was successful in 93.1% of patients, with a median CD34⁺ harvest of 8.7 × 10⁶ /kg. Target for 2 autologous stem cell transplantation (at least 6 CD34⁺  × 10⁶ /kg) was reached by 76.3% of patients. Administration of plerixafor on demand was necessary in 12.1% of patients.

CONCLUSIONS

Outpatient mobilization with low- and intermediate-dose cyclophosphamide appears an efficient and safe procedure, with minimal and manageable AEs and low rate of hospitalization.

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.

The Efficacy and Safety of Chemotherapy-Based Stem Cell Mobilization in Multiple Myeloma Patients Who Are Poor Responders to Induction: The Mayo Clinic Experience

We report the outcomes of 117 patients with newly diagnosed multiple myeloma who received novel agent induction, had a poor response to induction, and were mobilized using intravenous intermediate-dose cyclophosphamide (82%) or VD-PACE (18%) plus granulocyte colony-stimulating factor (G-CSF) and on-demand plerixafor. The median progression-free survival and overall survival of the chemo-mobilized cohort were 21 months (95% confidence interval [CI], 15-71) and 58 months (95% CI, 47-80), respectively. We compared our cohort to a 117-patient cohort matched by the level of response at pretransplant evaluation. The matched patients were mobilized with G-CSF and on-demand plerixafor without chemotherapy. Patients receiving chemo-mobilization had higher stem cell yields than the growth-factor-only cohort (median, 10.7 × 10⁶ cells/kg vs. 8.77 × 10⁶ cells/kg, respectively; P < .001). The safety profile of chemo-mobilization was favorable, and there was no difference between the two groups in length of hospitalization during autologous stem cell transplantation (P = .95), days to neutrophil engraftment (P = .22), days to platelet engraftment (P = .27), or risk of bacteremia (P = .52). Twenty-nine percent of the chemo-mobilized cohort and 65% of the matched cohort required plerixafor for adequate mobilization (P < .001). Chemo-mobilization enhances stem cell collection without adversely impacting the post-transplant clinical course.

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.

Low-Dose Cyclophosphamide versus Intermediate-High-Dose Cyclophosphamide versus Granulocyte Colony-Stimulating Factor Alone for Stem Cell Mobilization in Multiple Myeloma in the Era of Novel Agents: A Multicenter Retrospective Study

The optimal stem cell (SC) mobilization strategy for patients with multiple myeloma (MM) remains a matter of debate. Possible approaches include low or high doses of cyclophosphamide (Cy), other chemotherapeutic agents, or granulocyte colony-stimulating factor (G-CSF) alone. The scope of the study was to compare low-dose Cy plus G-CSF versus intermediate-high-dose Cy plus G-CSF versus G-CSF alone for SC mobilization in MM, in terms of efficacy and safety. We retrospectively analyzed 422 MM patients undergoing SC mobilization in 6 Italian centers, including 188 patients who received low-dose Cy (LD-Cy group, defined as 2 g/m²), 163 patients who received intermediate-high-dose Cy (HD-Cy group, defined as ≥ 3 g/m²), and 71 patients who received G-CSF alone (G-CSF group). The median peak of circulating CD34+ cells was 77/µL in the LD-Cy group, 92/µL in the HD-Cy group, and 55/µL in the G-CSF group (P = .0001). The median amount of SCs collected was 9.1 × 10⁶/kg, 9.7 × 10⁶/kg, and 5.6 × 10⁶/kg in the 3 groups, respectively (P = .0001). The rate of mobilization failure (defined as failure to collect ≥2 × 10⁶/kg) was 3.7% in the LD-Cy group, 3.4% in the HD-Cy group, and 4.3% in the G-CSF group (P = .9). The target SC dose of at least 4 × 10⁶/kg was reached in 90.4%, 91.1%, and 78.6% of the patients in these 3 groups, respectively (P = .014). The "on demand" use of plerixafor was higher in the G-CSF group (76%) compared with the LD-Cy group (19%) and the HD-Cy group (6%). In multivariate analysis, G-CSF mobilization and previous use of melphalan or radiotherapy were independently associated with failure to collect the target SC dose of ≥4 × 10⁶/kg. No impacts of age, blood counts, or previous treatment with lenalidomide, bortezomib, or carfilzomib were observed. Our results suggest that LD-Cy may be considered for successful SC mobilization in patients with MM.

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.

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.

Recombinant human thrombopoietin improves the efficacy of intermediate-dose cyclophosphamide plus granulocyte colony-stimulating factor in mobilizing peripheral blood stem cells in patients with multiple myeloma: A cohort study

The combination of intermediate-dose cyclophosphamide (ID-CTX) and granulocyte colony-stimulating factor (G-CSF) fails to mobilize peripheral blood stem cells (PBSCs) in approximately 20% of treated patients with multiple myeloma (MM).In this cohort study, patients with MM underwent PBSC mobilization with either an ID-CTX plus G-CSF plus recombinant human thrombopoietin (rhTPO) regimen (72 patients; TPO group), or an ID-CTX plus G-CSF regimen (70 patients; non-TPO group).In the TPO group, the median CD34+ harvest was 5.36 × 10 per kg of body weight (0.50-22.39 × 10 per kg of body weight), with a harvest success rate of 91.7% (66/72), and an excellence rate of 55.6% (40/72). In the non-TPO group, the median CD34+ harvest was 3.30 × 10 per kg of body weight (0.20-21.14 × 10 per kg of body weight), with a harvest success rate of 75.7% (53/70), and an excellence rate of 25.7% (18/70). The median count of the CD34+ cells collected, success rate of collection, and excellence rate of collection were significantly higher in the TPO group than in the non-TPO group (P=.0001, P=.01, and P = .0001, respectively). Time to granulocyte and platelet engraftment was faster among patients in the TPO group than that in those from the non-TPO group. No platelet engraftment delay (>21 days) was observed among patients in the TPO group, while 3 patients in the non-TPO group displayed delayed platelet engraftment.Adding rhTPO to the ID-CTX chemotherapy plus G-CSF regimen improved treatment efficacy in mobilizing PBSCs for autologous hematopoietic stem cell transplantation.

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.

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.

Is it feasible to use granulocyte-colony stimulating factor alone to mobilize progenitor cells in multiple myeloma patients induced with a cyclophosphamide, thalidomide and dexamethasone regimen?

BACKGROUND

Cyclophosphamide plus thalidomide as induction for multiple myeloma patients eligible for autologous stem cell transplantation may be a limiting factor for cell mobilization. The minimum acceptable mobilized peripheral blood stem cell count to prevent deleterious effects during transplantation is 2.0×10⁶ CD34⁺ cells/kg. Combining other treatments to granulocyte-colony stimulating factor, such as cyclophosphamide, could overcome the mobilization limitation. The objective of this study was to assess the number of CD34⁺ cells mobilized using granulocyte-colony stimulating factor with and without cyclophosphamide after induction with cyclophosphamide, thalidomide and dexamethasone.

METHODS

A retrospective study was performed of a cohort of multiple myeloma patients submitted to autologous stem cell transplantations at two Brazilian centers between May 2009 and July 2013. The oral cyclophosphamide and thalidomide induction doses used were 1500mg/month and 100-200mg/day, respectively. Mobilization doses were 10-15mcg/kg granulocyte-colony stimulating factor with 2-4g/m² cyclophosphamide, or 15-20mcg/kg granulocyte-colony stimulating factor alone for 5 days. Collection of >2.0×10⁶ CD34⁺ cells/kg was considered sufficient.

RESULTS

Eighty-eight patients were analyzed; only 18 received cyclophosphamide. The median age was 58 years old (range: 51-62) for the granulocyte-colony stimulating factor group and 56.5 years old (range: 54-60) for granulocyte-colony stimulating factor plus cyclophosphamide group. Fifty-two patients were male. Eighty cases (90.9%) were Durie-Salmon Staging System III-A/B and 38 (44.7%) and 20 cases (23.5%) were International Staging System 2 and 3, respectively. The group that received cyclophosphamide collected a higher median number of progenitor cells [3.8 (range: 3.1-4.4) vs. 3.2 (range: 2.3-3.8)] (p-value=0.008). No correlation was observed between better responses or number of induction cycles and the number of cells collected.

CONCLUSION

The number of cells mobilized with granulocyte-colony stimulating factor plus cyclophosphamide was higher. However, in both groups, the median number of CD34⁺ cells was sufficient to perform a single autologous stem cell transplantation; no deleterious effects were reported during harvesting.

Selection of a mobilization regimen for multiple myeloma based on the response to induction therapy: granulocyte-colony stimulating factor (G-CSF) alone versus high-dose cyclophosphamide plus G-CSF

To evaluate the feasibility of selecting a mobilization regimen based on the response to induction therapy, we retrospectively analyzed 179 multiple myeloma patients who underwent stem cell mobilization. In comparison with patients who achieved at least a very good partial response (VGPR) to induction therapy and received granulocyte-colony stimulating factor (G-CSF) alone and patients who did not achieve a VGPR and received cyclophosphamide (CY) + G-CSF, treatment-related toxicity was greater and neutrophil engraftment was slower in the CY than the G-CSF group. The rate of requisite mobilization (≥ 2.0 × 10(6)/kg) was similar in both groups. Overall and progression-free survival was not different between patients in the G-CSF group and patients who achieved at least VGPR and received CY + G-CSF. In conclusion, response-adapted selection of a mobilization regimen is appropriate. G-CSF alone should be the preferred treatment for patients who achieved at least a VGPR to induction therapy.

A randomized phase II study of stem cell mobilization with cyclophosphamide+G-CSF or G-CSF alone after lenalidomide-based induction in multiple myeloma

The most common means of mobilizing autologous stem cells is G-CSF alone or combined with cyclophosphamide (CY) to obtain sufficient CD34⁺ cells for one to two transplants. There are few prospective, randomized studies investigating mobilization regimens in multiple myeloma (MM), especially after lenalidomide-based induction. We designed this prospective, randomized study to compare low-dose CY 2 g/m²+G-CSF (arm A) and G-CSF alone (arm B) after lenalidomide-based up-front induction in MM. Of the 80 initially randomized patients, 69 patients were evaluable, 34 and 35 patients in arms A and B, respectively. The primary end point was the proportion of patients achieving a yield of ⩾3 × 10⁶/kg CD34⁺ cells with 1−2 aphereses, which was achieved in 94% and 77% in arms A and B, respectively (P=0.084). The median number of aphereses needed to reach the yield of ⩾3 × 10⁶/kg was lower in arm A than in arm B (1 vs 2, P=0.035). Two patients needed plerixafor in arm A and five patients in arm B (P=0.428). Although CY-based mobilization was more effective, G-CSF alone was successful in a great majority of patients to reach the defined collection target after three cycles of lenalidomide-based induction.

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.

Optimizing mobilization strategies in difficult-to-mobilize patients: The role of plerixafor

Peripheral blood stem cell collection is currently the most widely used source for hematopoietic autologous transplantation. Several factors such as advanced age, previous chemotherapy, disease and marrow infiltration at the time of mobilization influence the efficacy of CD34(+) progenitor cell mobilization. Despite the safety and efficiency of the standard mobilization protocols (G-CSF ± chemotherapy), there is still a significant amount of mobilization failure rate (10-40%), which necessitate novel agents for effective mobilization. Plerixafor, is a novel agent, has been recently approved for mobilization of hematopoietic stem cells (HSCs). The combination of Plerixafor with G-CSF provides the collection of large numbers of stem cells in fewer apheresis sessions and can salvage those who fail with standard mobilization regimens. The development and optimization of practical algorithms for the use Plerixafor is crucial to make hematopoietic stem cell mobilization more efficient in a cost-effective way. This review is aimed at summarizing how to identify poor mobilizers, and define rational use of Plerixafor for planning mobilization in hard-to-mobilize patients.

Peripheral blood stem cell mobilization failure

Autologous hematopoietic stem cell transplantation (HSCT) is an important and often life saving treatment for many hematological malignancies and selected solid tumors. To rescue hematopoiesis after high-dose chemotherapy in autologous HSCT depends on maintaining sufficient stem cells. Hematopoietic stem cells and progenitor cells expressing CD34 in the BM are mobilized into the circulation with granulocyte-colony stimulating factor ± chemotherapy prior to autologous HSCT. One of the most important factors for success of autologous HSCT is hematopoietic stem cell (HSC) count. Minimum threshold for the engraftment of hematopoietic cells is accepted as 2 × 10(6) CD34 + cells/kg especially for platelet engraftment. Below this level it is defined as stem cell mobilization failure. There are several factors affecting stem cell mobilization: prior chemotherapy (such as fludarabine, melphalan, lenalidomide) and radiotherapy, age, type of disease, bone marrow cellularity. We tried to summarize the reasons of peripheral stem cell mobilization failure.

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.

Advances in stem cell mobilization

Use of granulocyte colony stimulating factor (G-CSF)-mobilized peripheral blood hematopoietic progenitor cells (HPCs) has largely replaced bone marrow (BM) as a source of stem cells for both autologous and allogeneic cell transplantation. With G-CSF alone, up to 35% of patients are unable to mobilize sufficient numbers of CD34 cells/kg to ensure successful and consistent multi-lineage engraftment and sustained hematopoietic recovery. To this end, research is ongoing to identify new agents or combinations which will lead to the most effective and efficient stem cell mobilization strategies, especially in those patients who are at risk for mobilization failure. We describe both established agents and novel strategies at various stages of development. The latter include but are not limited to drugs that target the SDF-1/CXCR4 axis, S1P agonists, VCAM/VLA-4 inhibitors, parathyroid hormone, proteosome inhibitors, Groβ, and agents that stabilize HIF. While none of the novel agents have yet gained an established role in HPC mobilization in clinical practice, many early studies exploring these new pathways show promising results and warrant further investigation.

The effect of gradual increment in rhG-CSF dose on stem cell yields in patients with multiple myeloma mobilized with intermediate dose cyclophosphamide plus rhG-CSF

Cyclophosphamide along with recombinant human granulocyte-colony stimulating factor (rhG-CSF) is a commonly used strategy for mobilization. However, the optimal timing for rhG-CSF initiation after cyclophosphamide has not been determined as conclusively as has the G-CSF dose. In this paper, we aimed to present gradual dose increment of rhG-CSF between the third day of mobilization and time to apheresis that is started with 5 μg/kg (from day 3 to day 7) and continued with 10 μg/kg (from day 8 to time to apheresis) for peripheral blood stem cell (PBSC) mobilization in multiple myeloma (MM) patients and its effect on stem cell yield and mobilization success. Data from 30 consecutive patients with MM who underwent PBSC mobilization between October 2011 and June 2013, were retrospectively reviewed. While twenty-eight of 30 patients (93.3%) were successfully mobilized, 2 patients (6.7%) had mobilization failure. The final median CD34+ cell dose harvested from the patients was 9.5×10(6)/kg. The median number of apheresis was 2.5 (range, 0-3). Twenty-four patients (80%) yielded >2×10(6) CD34+ cells/kg in one apheresis procedure. In conclusion, our regimen might be used to decrease the mobilization failure regarding the low dose rhG-CSF use and provide a cost effective strategy.

Safety and efficacy of upfront plerixafor + G-CSF versus placebo + G-CSF for mobilization of CD34(+) hematopoietic progenitor cells in patients ≥60 and <60 years of age with non-Hodgkin's lymphoma or multiple myeloma

The efficacy and safety of plerixafor + G-CSF in enhancing hematopoietic stem cell mobilization and collection has been demonstrated in two phase III studies involving patients with NHL or MM. In these pivotal studies, plerixafor + G-CSF significantly increased the proportion of patients achieving target stem cell yields, compared to placebo + G-CSF. In this analysis, we compare the efficacy and safety of plerixafor + G-CSF versus placebo + G-CSF in patients enrolled in the two phase III studies, stratified by age: ≥60 years of age and <60 years of age. The proportion of older patients who achieved target stem cell yields was significantly higher in the plerixafor group than in placebo group (NHL: 50.9 vs. 25.4%, P < 0.001; MM: 69.6 vs. 23.7%, P < 0.001). In this older cohort, the median times to neutrophil and to platelet engraftment following autologous stem cell transplant were comparable between the plerixafor and placebo groups. Similar efficacy findings were observed in the younger age group. The most common adverse events (all grades) reported among older patients in the plerixafor group included diarrhea (41.3%), nausea (38.9%), fatigue (30.2%), and injection-site reaction (29.4%). The frequency of adverse events was similar between the older and the younger age groups. Taken together, our subanalysis demonstrate that plerixafor + G-CSF can be safely and effectively used in adult patients of all ages, including those ≥60 years, to support optimal stem cell mobilization for autologous stem cell transplantation.

Peripheral blood stem cell mobilization in multiple myeloma patients treat in the novel therapy-era with plerixafor and G-CSF has superior efficacy but significantly higher costs compared to mobilization with low-dose cyclophosphamide and G-CSF

Studies comparing the efficacy and cost of peripheral blood stem and progenitor cells mobilization with low-dose cyclophosphamide (LD-CY) and granulocyte-colony stimulating factor (G-CSF) against plerixafor and G-CSF, in multiple myeloma (MM) patients treated in the novel therapy-era are not available. Herein, we report mobilization outcomes of 107 patients who underwent transplantation within 1-year of starting induction chemotherapy with novel agents. Patients undergoing mobilization with LD-CY (1.5 gm/m(2)) and G-CSF (n = 74) were compared against patients receiving plerixafor and G-CSF (n = 33). Compared to plerixafor, LD-CY was associated with a significantly lower median peak peripheral blood CD34+ cell count (68/µL vs. 36/µL, P = 0.048), and lower CD34+ cell yield on day 1 of collection (6.9 × 10(6)/kg vs. 2.4 × 10(6)/kg, P = 0.001). Six patients (8.1%) in the LD-CY group experienced mobilization failure, compared to none in the plerixafor group. The total CD34+ cell yield was significantly higher in the plerixafor group (median 11.6 × 10(6)/kg vs. 7 × 10(6)/kg; P-value = 0.001). Mobilization with LD-CY was associated with increased (albeit statistically non-significant) episodes of febrile neutropenia (5.4% vs. 0%; P = 0.24), higher use of intravenous antibiotics (6.7% vs. 3%; P = 0.45), and need for hospitalizations (9.4% vs. 3%; P = 0.24). The average total cost of mobilization in the plerixafor group was significantly higher compared to the LD-CY group ($28,980 vs. $19,626.5 P-value < 0.0001). In conclusion, in MM plerixafor-based mobilization has superior efficacy, but significantly higher mobilization costs compared to LD-CY mobilization. Our data caution against the use of LD-CY in MM patients for mobilization, especially after induction with lenalidomide-containing regimens.

The evolving role of plerixafor in hematopoietic progenitor cell mobilization

The introduction of plerixafor as a peripheral blood stem cell mobilization agent has allowed more patients with multiple myeloma, non-Hodgkin's lymphoma, and Hodgkin's disease to mobilize sufficient hematopoietic progenitor cells (HPCs) to proceed to autologous transplantation. Because of the high cost of plerixafor, it is not routinely used in all patients undergoing HPC mobilization. If cost were not an issue, an argument could be made that plerixafor could be added to every mobilization regimen, but cost is an issue so in an attempt to be more cost-effective, many centers have limited plerixafor use to patients who have failed or who are predicted to fail collection of adequate numbers of cells by other methods. Additionally, plerixafor is now under investigation both for HPC collection of healthy donors for allogeneic stem cell transplantation and as an adjunct therapy (i.e., chemosensitizing agent) for acute leukemias. This article briefly reviews the role of plerixafor in autologous and allogeneic transplantation as well as its emerging role in the treatment of acute leukemias. Emphasis is placed on the choice of appropriate patients for plerixafor use to assure an adequate stem cell yield while maximizing the cost effectiveness of using plerixafor. The role of prophylactic collections and future areas of research are also presented.

Early measurement of CD34+ cells in peripheral blood after cyclophosphamide and granulocyte colony-stimulating factor treatment predicts later CD34+ mobilisation failure and is a possible criterion for guiding "on demand" use of plerixafor

BACKGROUND

Early identification of predictive factors of failure to mobilise CD34+ cells could enable rational use of plerixafor during first mobilisation, avoiding the need for a second mobilisation course. However, "on demand" administration of plerixafor needs to be driven by established parameters to avoid inappropriate use.

MATERIALS AND METHODS

To address this issue, we studied the value of the peripheral blood CD34+ count, measured early (on days +10, +11, +12 and +13), in predicting the mobilisation outcome in the ensuing days. We retrospectively collected data from three Italian centres on 233 patients affected by multiple myeloma or lymphoma who underwent a first or second attempt at mobilisation with cyclophosphamide 4 g/m(2) and granulocyte colony-stimulating factor. To assess the diagnostic value of peripheral blood white blood cell and CD34+ cell counts with respect to "mobilisation failure", we considered failed mobilisation as "disease" and the CD34+ cell count in peripheral blood, on a specific day, as a "diagnostic test". For various thresholds, we measured sensitivity, false positive rate, specificity and positive predictive value (PPV) as well as the area under the receiver-operating characteristic curves (AUC).

RESULTS

A CD34+ cell count <10 × 10(6)/L on day 13 had high sensitivity (1.00) and high specificity (1.00) for predicting subsequent mobilisation failure, with an AUC of 1.0. However, good prediction was also obtained using a lower threshold (CD34+ cell count: <6 × 10(6)/L) at an earlier time (day 12). The PPV of the day 13 threshold was 1.00 while that of the day 12 one was 0.87.

DISCUSSION

We propose that patients with <6 × 10(6)/L CD34+ cells in peripheral blood on day 12 and <10 × 10(6)/L on day 13 following mobilisation with cyclophosphamide 4 g/m(2) and granulocyte colony-stimulating factor are candidates for "on demand" use of plerixafor, making the administration of this expensive agent more efficient and avoiding its inappropriate use.

New strategies for stem cell mobilization

Mobilized peripheral blood (PB) is widely used as source of stem cells (PBSCs) for autologous stem cell transplantation (ASCT). The use of cytokines, alone or in combination with chemotherapy (chemomobilization), is the most common strategy applied to mobilize and collect PBSCs. However, a significant proportion of cancer patients fail to mobilize enough PBSCs to proceed to ASCT. Plerixafor is a small molecule that reversibly and transiently disrupts the interaction between the chemokine receptor CXCR4 and its ligand CXCL12 (formerly known as stroma derived factor 1, SDF-1) leading to the rapid release of CD34⁺ hematopoietic stem cells from the bone marrow (BM) to PB. Plerixafor has been recently approved to enhance PBSC mobilization in adult patients with multiple myeloma or non-Hodgkin lymphoma and has been shown to be more effective than G-CSF alone. There is limited experience on combining plerixafor with chemotherapy plus G-CSF in patients who mobilize poorly. Current evidence suggests that the addition of plerixafor is safe and effective in the large majority of the patients with low blood CD34⁺ cell count after mobilization and/or poor yield after the first collection(s). Circulating CD34⁺ cells can be increased by several folds with plerixafor and the majority of the patients considered “poor mobilizers” can be successfully collected. Overall, its mechanism of action inducing the rapid release of CD34⁺ cells from the BM to the circulation makes plerixafor suitable for the ‘preemptive’ use in patients who are hard-to-mobilize.

[Hematopoietic stem cells mobilization: state of the art in 2011 and perspectives]

High-dose chemotherapy with stem cells support has largely improved in terms of hematopoietic stem and progenitor cells harvest procedures as well as in those, which target or manipulate the cellular composition of autologous graft. Optimal preparative regimens and supportive care had lead to better use of autologous transplantation procedure. For other patients assigned to hematopoietic transplantation, availability of allogeneic donors appears to be an interesting alternative source of hematopoietic stem cells. Since three decades, hematopoietic growth factors development has allowed mobilization optimization and collection of peripheral hematopoietic stem cells leading to reduced days of hospitalization and less blood products requirements, being more cost-effective for patients in autologous transplantation settings and for stem cell collection facilities in allogeneic ones. New perspectives include, besides ex vivo manipulation of graft, development of mobilizing drugs in order to perform transplantation even in poor mobilizers patients. An important goal is achieved with the description of genetic polymorphisms related to optimal mobilization of stem cells. New approach using more promising and selective agents called chemokines, such as plerixafor the main leader among these agents are now available and appear complementary for alternative approach using cytokines alone (G-CSF, GM-CSF, SCF). The aim of this review is to assess the evolution of theses biotechnologies and their role in different steps of autologous transplantation and allogeneic stem cells collection.

Assessing the charges associated with hematopoietic stem cell mobilization and remobilization in patients with lymphoma and multiple myeloma undergoing autologous hematopoietic peripheral blood stem cell transplantation

BACKGROUND

The purpose of this study was to perform a detailed analysis of the charges associated with chemomobilization and remobilization of autologous hematopoietic stem cells (HSCs) and to quantify medical costs and resource utilization associated with these procedures.

STUDY DESIGN AND METHODS

Patients with lymphoma underwent chemomobilization with ifosfamide and etoposide with or without rituximab (IE ± R). Patients with multiple myeloma (MM) received a modified hyperfractionated cyclophosphamide, vincristine, doxorubicin, dexamethasone (hyper-CVAD) regimen after failing to mobilize with growth factors only.

RESULTS

Between January 2004 and October 2006, 98 patients with lymphoma underwent HSC mobilization with IE ± R. Mobilization with IE ± R was effective, with 90.8% of patients collecting at least 2 × 10(6) CD34+ cells/kg. The total charges for treatment were $27,996 and $37,667 for patients mobilized with IE and IE + R, respectively. Hospital readmission for complications occurred in 26.5% of patients, resulting in additional charges of $10,356. The preapheresis procedure charge was estimated to be $2522, the charge for a 2-day apheresis session was $5160, and the postapheresis phase resulted in charges of $8040. Our analysis determined that reducing apheresis by 1 day has the potential to save $6600. We also performed a retrospective analysis of 16 patients with MM remobilized with a modified hyper-CVAD regimen. Remobilization was successful, with 87.5% of patients. Our analysis determined that mobilization, preapheresis, apheresis, and postapheresis phase charges were $24,968, $2522, $6158, and $12,060, respectively.

CONCLUSIONS

Optimization of HSC mobilization regimens to reduce failure rates would not only benefit patients but also reduce the overall medical costs.

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.