Haematopoietic stem cell mobilization with plerixafor and G-CSF in patients with multiple myeloma transplanted with autologous stem cells

Stem Cell Mobilization Performed with Different Doses of Cytarabine in Plasma Cell Myeloma Patients Relapsing after Previous Autologous Hematopoietic Cell Transplantation-A Multicenter Report by the Polish Myeloma Study Group

Salvage autologous hematopoietic cell transplantation (auto-HCT) may be used to treat relapse of plasma cell myeloma occurring after previous auto-HCT. When an insufficient number of hematopoietic stem cells have been stored from the initial harvest, remobilization is necessary. Here, we aimed to analyze the efficacy and safety of different doses of cytarabine (total 800 vs. 1600 vs. 2400 mg/m2) for remobilization. Sixty-five patients, 55% male, with a median age at remobilization 63 years, were included. Remobilization was performed with cytarabine_800 in 7, cytarabine_1600 in 36, and cytarabine_2400 in 22 patients. Plerixafor rescue was used in 25% of patients receiving cytarabine_1600 and 27% of those receiving cytarabine_2400. Patients administered cytarabine_800 were not rescued with plerixafor. Remobilization was successful in 80% of patients (57% cytarabine_800; 86% cytarabine_1600; 77% cytarabine_2400; p = 0.199). The yield of collected CD34+ cells did not differ between the different cytarabine doses (p = 0.495). Patients receiving cytarabine_2400 were at the highest risk of developing severe cytopenias, requiring blood product support, or having blood-stream infections. One patient died of septic shock after cytarabine_2400. In summary, remobilization with cytarabine is feasible in most patients. All doses of cytarabine allow for successful remobilization. Cytarabine_2400 is associated with higher toxicity; therefore, lower doses (800 or 1600 mg/m2) seem to be preferable.

Etoposide combined with cytarabine and pegfilgrastim for poorly mobilizing patients with multiple myeloma and lymphoma: A prospective multicentre study

A chemotherapy-based mobilization regimen in patients who mobilize poorly, based on etoposide, cytarabine and pegfilgrastim (EAP), has recently been introduced. The aim of this prospective study was to investigate the efficacy and safety of the EAP regimen in patients with poorly mobilizing multiple myeloma (MM) or lymphoma. This single-arm clinical trial was performed at eight public hospitals in China and was registered as a clinical trial (NCT05510089). The inclusion criteria were; (1) diagnosis of MM or lymphoma, (2) defined as a 'poor mobilizer' and (3) aged 18-75 years. The EAP regimen consisted of etoposide 75 mg/m2/day on days 1-2, cytarabine 300 mg/m2 every 12 h on days 1-2 and pegfilgrastim 6 mg on day 6. The primary endpoint of the study was the ratio of patients achieving adequate mobilization (≥2.0 × 106 CD34+ cells/kg). From 1 September 2022 to 15 August 2023, a total of 58 patients were enrolled, 53 (91.4%) achieved adequate mobilization, while 41 (70.7%) achieved optimal mobilization with a median number of cumulative collected CD34+ cells was 9.2 (range 2.1-92.7) × 106/kg and the median number of apheresis per patient of 1.2. The median time from administration of the EAP regimen to the first apheresis was 12 days. Approximately 8.6% of patients required plerixa for rescue, which was successful. Twelve (20.7%) of the 58 patients suffered grade 2-3 infections, while 25 (43.1%) required platelet transfusions. The duration of neutrophil and platelet engraftment was 11 days. In conclusion, these results suggest that the EAP mobilization regimen might be a promising option for poorly mobilizing patients with MM or lymphoma.

Cryopreservation and storage patterns of hematopoietic progenitor stem cells for multiple myeloma

Autologous hematopoietic stem cell transplantation (HCT) has been a standard of care treatment for eligible patients with newly diagnosed multiple myeloma (MM). Guidelines generally recommend hematopoietic progenitor cell (HPC) harvest for two potential HCT. There is a paucity of data reporting use of such collections in the era of novel approved therapies. In this single-center retrospective study, our goal was to determine the HPC utilization rate and costs associated with leukocytapheresis, collection, storage, and disposal to guide future HPC collection planning. We included 613 patients with MM who underwent HPC collection over a nine-year period. The patients were separated into four groups based on HPC utilization: 1) patients who never proceeded to HCT, or Harvest and Hold (14.8 %), 2) patients who proceeded to one HCT with banked HPC remaining (76.8 %), 3) patients who proceeded to one HCT without HPC remaining (5.1 %), and 4) patients who proceeded to two HCTs (3.3 %). After collection, 73.9 % of patients underwent HCT within 30 days. Of patients with banked HPC, defined as not undergoing HCT within 30 days of leukocytapheresis, the overall utilization rate was 14.9 %. At 2- and 5-years post HPC collection, utilization rate was 10.4 % and 11.5 %, respectively. In conclusion, our results suggest very low utilization of stored HPC, raising into question the current HPC collection targets. Given advances in MM therapy, as well as significant costs associated with harvest and storage, collection for unplanned future use warrants reconsideration. As a result of our analysis, our institution has reduced our HPC collection targets.

Higher efficacy of Etoposide + Cytarabine Plus Pegfilgrastim in poorly mobilizing Multiple Myeloma and lymphoma Patients

BACKGROUND AIMS

An optimal strategy for mobilizing hematopoietic stem cells in poorly mobilizing patients with multiple myeloma (MM) and lymphoma has not yet been determined.

METHODS

We retrospectively analyzed the efficacy and safety of etoposide combined with cytarabine (etoposide 75 mg/m2, daily d1∼2; Ara-C 300 mg/m2, every 12 h d1∼2), plus pegfilgrastim (6 mg d6) in 32 patients with MM or lymphoma, among whom 53.1% were defined as "proven poor mobilizers."

RESULTS

This approach resulted in adequate mobilization (≥2.0 × 106 CD34+ cells/kg) in 93.8% of patients and optimal mobilization (≥5.0 × 106 CD34+ cells/kg) in 71.9% of patients. A total of 100% of patients with MM reached at least 5 × 106 CD34+ cells/kg collected, the amount required for double autologous stem cell transplant. In total, 88.2% of patients with lymphoma reached at least 2 × 106 CD34+ cells/kg collected, the amount required for a single autologous stem cell transplant. This was achieved with a single leukapheresis in 78.1% of cases. A median peak number of 42.0/μL circulating CD34+ cells and a median number of blood CD34+ cells counts in 6.7 × 106/L were collected among 30 successful mobilizers. Approximately 6.3% of patients required plerixafor rescue, which was successful. Nine (28.1%) of the 32 patients suffered grade 2∼3 infections, and 50% required platelet transfusions.

CONCLUSIONS

We conclude that chemo-mobilization with etoposide, Ara-C and pegfilgrastim in poorly mobilizing patients with MM or lymphoma is very effective and has acceptable toxicity.

Autologous hematopoietic cell transplantation for relapsed multiple myeloma performed with cells procured after previous transplantation-study on behalf of CMWP of the EBMT

Autologous hematopoietic cell transplantation (auto-HCT) may be performed in multiple myeloma (MM) patients relapsing after a previous auto-HCT. For those without an adequate dose of stored stem cells, remobilization is necessary. This retrospective study included patients who, following disease relapse after the first auto-HCT(s), underwent stem cell remobilization and auto-HCT performed using these cells. There were 305 patients, 68% male, median age at salvage auto-HCT was 59 years. The median time to relapse after the first-line penultimate auto-HCT(s) was 30.6 months, the median follow-up after salvage auto-HCT 31 months. The 2- and 4-year non-relapse mortality (NRM) after the salvage auto-HCT was 5 and 9%, the relapse incidence 56 and 76%, respectively. Overall survival (OS) after 2 and 4 years was 76 and 52%, progression-free survival (PFS) 39 and 15%. In multivariable analysis an increasing interval between the penultimate auto-HCT and relapse was associated with better OS and PFS, later calendar year of salvage auto-HCT with better OS. In conclusion, salvage auto-HCT performed with cells remobilized after a previous auto-HCT was associated with acceptable NRM. The leading cause of failure was disease progression of MM, which correlated with a shorter interval from the penultimate auto-HCT to the first relapse.

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.

Stem cell mobilization in multiple myeloma patients relapsing after previous autologous hematopoietic stem cell transplantation: A multicenter report by the Polish Myeloma Study Group

BACKGROUND

Salvage autologous hematopoietic stem cell transplantation (autoHSCT) may be used to treat relapse of multiple myeloma occurring after previous autoHSCT. When insufficient number of hematopoietic stem cells was stored from the initial harvest, remobilization of stem cells is necessary.

PURPOSE

The analysis of stem cell remobilization after previous autoHSCT.

PATIENTS AND METHODS

Fifty-eight patients, 60% males, median 59 years, were included. Median time interval between autoHSCT and remobilization was 42 months. The first remobilization was performed mostly after chemotherapy: cyclophosphamide (33%), cytarabine (43%), and etoposide (19%).

RESULTS

The first remobilization was successful in 67% patients. About 19% patients required plerixafor rescue, among whom it allowed for successful harvesting in 14%. Use of cyclophosphamide, cytarabine, and etoposide allowed for successful remobilization in 53%, 84%, and 55% patients, respectively. Patients treated with cytarabine had the highest yield of CD34+ cells (median 7.5 × 10⁶ /kg vs 5.8 and 2.4 for etoposide and cyclophosphamide, P = .001). Higher percentage of patients was able to collect ≥2 × 10⁶ CD34+ cells/kg during one leukapheresis after cytarabine (76% vs 21% for cyclophosphamide vs 36% for etoposide, P = .001). Cytarabine use was associated with lower risk of remobilization failure OR = 0.217, P = .02. Toxicity comprised mostly hematological toxicity (thrombocytopenia and neutropenia). One patient succumbed to septic shock.

CONCLUSION

Remobilization after previous autoHSCT is feasible only in a proportion of patients. Cytarabine is associated with the highest rate of successful mobilization and the highest yield of mobilized CD34+ cells. The toxicity requires careful surveillance of these patients.

The Efficacy and Safety of Plerixafor in Hematopoietic Stem Cell Mobilization in Patients with Non-Hodgkin Lymphoma, Multiple Myeloma, and Hodgkin Lymphoma Who Failed Mobilization with Granulocyte-Colony-Stimulating Factor Alone: A Single-Center Experience

Plerixafor is a CXCR4 antagonist which is administered along with granulocyte-colony-stimulating factor (G-CSF) to mobilize hematopoietic stem cells in patients with Non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), who failed the mobilization with G-CSF alone.

This was a single-center, retrospective study of the efficacy of the plerixafor and G-CSF in 32 patients with NHL (n = 11), MM (n = 11), and Hodgkin lymphoma (HL) (n = 10) who failed mobilization with G-CSF alone.

A median number of 1.21 × 106, 1.32 × 106, and 6.73 × 106 CD34 + cells were mobilized in patients with MM, NHL, and HL, respectively. Overall, 31 (96.8%) patients mobilized more than 2 × 106 CD34 + stem cells and 21 (33.75%) patients mobilized more than 5 × 106 CD34 + stem cells. All 32 (100%) patients underwent hematopoietic stem cell transplantation. There were no adverse drug events reported.

This retrospective study shows that plerixafor is an effective and safe mobilization agent in patients with NHL, MM, and HL who have failed mobilization with G-CSF alone.

Plerixafor-aided Mobilization of Peripheral Blood Hematopoietic Stem Cells to Support Subsequent High-dose Chemotherapy After a Prior Autologous Transplant

BACKGROUND

An appreciable proportion of patients in need of salvage high-dose chemotherapy (HDC) and autologous peripheral blood stem cell (PBSC) transplantation (PBSCT) fail to mobilize adequate numbers of hematopoietic progenitors, and plerixafor is applied for that purpose. Limited data exist on remobilization of PBSCs in patients who have relapsed after prior HDC + PBSCT. Herein, we report on consecutive patients that had undergone successful prior single or tandem HDC for a variety of malignant neoplasms in our institution, and later required re-mobilization of PBSCs in order to support further HDC cycles.

PATIENTS AND METHODS

Plerixafor was administered in combination with granulocyte-colony stimulating factor alone, or after mobilizing chemotherapy. Five patients, 2 B-cell non-Hodgkin lymphomas, 1 multiple myeloma, 1 germ-cell tumor, and 1 Ewing sarcoma, having relapsed after prior HDC + PBSCT, were deemed candidates for further cycle(s) of PBSC-supported HDC. Plerixafor was applied in a "just-in-time" strategy after low CD34+ numbers were measured on the first day of anticipated hematopoietic stem cell collection (non-Hodgkin lymphoma, germ-cell tumor, and Ewing sarcoma), or pre-emptively in multiple myeloma.

RESULTS

Successful collection of adequate PBSCs was achieved in all patients, from 1.8 to 3.8 × 10⁶/kg after a median of 2 (range, 1-3) leukaphereses; 4 of 5 patients underwent subsequent HDC + PBSCT and engrafted after a median of 11 days (range, 9-55 days) and 25 days (range, 17-76 days) for neutrophils and platelets, respectively.

CONCLUSION

Plerixafor proved effective to mobilize adequate numbers of PBSCs in individual patients with relapsed malignancies after prior single or tandem HDC + PBSCT. These PBSCs could establish sustained multi-lineage hematopoietic engraftment without any sequelae.

The Biological and Clinical Relevance of G Protein-Coupled Receptors to the Outcomes of Hematopoietic Stem Cell Transplantation: A Systematized Review

Hematopoietic stem cell transplantation (HSCT) remains the only curative treatment for several malignant and non-malignant diseases at the cost of serious treatment-related toxicities (TRTs). Recent research on extending the benefits of HSCT to more patients and indications has focused on limiting TRTs and improving immunological effects following proper mobilization and engraftment. Increasing numbers of studies report associations between HSCT outcomes and the expression or the manipulation of G protein-coupled receptors (GPCRs). This large family of cell surface receptors is involved in various human diseases. With ever-better knowledge of their crystal structures and signaling dynamics, GPCRs are already the targets for one third of the current therapeutic arsenal. The present paper assesses the current status of animal and human research on GPCRs in the context of selected HSCT outcomes via a systematized survey and analysis of the literature.

Etoposide + Granulocyte Colony-Stimulating Factor and Optional Plerixafor in Patients Who Failed Chemomobilization with or without Plerixafor

We conducted a retrospective study of 62 patients undergoing etoposide (2 g/m²) + granulocyte colony-stimulating factor (G-CSF; 10 patients also received additional plerixafor) as a salvage stem cell mobilization regimen after previous unsuccessful chemomobilization with or without plerixafor. The median peak CD34⁺ values after etoposide + G-CSF ± plerixafor was 54.07 CD34⁺/μL compared with 9.6 CD34⁺/μL after previous mobilization attempts (P < .001). The median yield was 6.33 × 10⁶ CD34⁺ cells/kg per 2 apheresis. Etoposide + G-CSF ± plerixafor mobilization regimen resulted in 91.53% successful mobilizations and 89.83% of patients proceeding to autologous stem cell transplantation. All 7 patients who had previously failed plerixafor-based mobilization attempts were successfully mobilized with etoposide + G-CSF ± plerixafor and proceeded to autologous stem cell transplantation. The most common grades 3 to 4 adverse events of etoposide + G-CSF ± plerixafor were febrile neutropenia (69.35%), mucositis (51.62%), and bacteremia (20.97%). No fatal outcomes were observed. Rates of 12-month overall survival and progression-free survival were 88.71% and 70.97%, respectively. Etoposide + G-CSF ± plerixafor is an effective regimen for salvage stem cell mobilization also in patients who failed plerixafor, with most patients undergoing autologous stem cell transplantation. The adverse event rate may warrant a decrease in the dose of etoposide.

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

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

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

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

Myeloablative chemotherapy and autologous stem cell transplantation can lead to successful postengraftment mobilization of hematopoietic progenitors to support planned subsequent cycle(s) of high-dose chemotherapy and autografting in a patient with relapsed germ-cell tumor

Salvage high-dose chemotherapy (HDC) together with autologous hematopoietic stem cell (HSC) transplantation (ASCT) represents a curative treatment option for patients with relapsed/refractory germ-cell tumor. Usually, 2-3 cycles of HDC are administered with encouraging results, and a sizeable percentage of patients experience long-term survival. However, an appreciable number of patients fail to mobilize adequate numbers of HSCs, adequate to support more than one HDC cycle. There have been no data so far on remobilization of HSCs after prior autografting. We report a unique case with relapsed germ-cell tumor that had undergone the first cycle of HDC with myeloablative doses of carboplatin-etoposide, and HSCs were mobilized successfully in the early posthematopoietic engraftment period to support further cycles of HDC. Four weeks after the first ASCT, an identical second cycle of myeloablative HDC was administered and rescued successfully with the HSCs collected after engraftment following the previous HDC cycle. The present case report illustrates that HSCs can be mobilized successfully in the early postengraftment period after myeloablative doses of carboplatin-etoposide, and these cells can be applied as the sole source of hematopoietic rescue in planned sequential cycles of myeloablative HDC, leading to successful multilineage engraftment. Provided that more extensive experience is gathered in future studies in large numbers of patients, this strategy could prove helpful in patients who cannot initially collect sufficient HSC numbers, before the first autografting cycle, and are in need of sequential HDC+ASCT cycles. A detailed literature review is provided to highlight the uniqueness of the presented case.

Plerixafor Plus Granulocyte Colony-Stimulating Factor for Patients with Non-Hodgkin Lymphoma and Multiple Myeloma: Long-Term Follow-Up Report

The purpose of this report is to analyze long-term clinical outcomes of patients exposed to plerixafor plus granulocyte colony-stimulating factor (G-CSF) for stem cell mobilization. This was a study of patients with non-Hodgkin lymphoma (NHL; n = 167) and multiple myeloma (MM; n = 163) who were enrolled in the long-term follow-up of 2 pivotal phase III studies (NCT00741325 and NCT00741780) of 240 µg/kg plerixafor plus 10 µg/kg G-CSF, or placebo plus 10 µg/kg G-CSF to mobilize and collect CD34⁺ cells for autologous hematopoietic stem cell transplantation. Overall survival (OS) and progression-free survival (PFS) were evaluated over a 5-year period following the first dose of plerixafor or placebo. The probability of OS was not significantly different in patients with NHL or MM treated with plerixafor or placebo (NHL: 64%; 95% confidence interval [CI], 56% to 71% versus 56%; 95% CI, 44% to 67%, respectively; MM: 64%; 95% CI, 54% to 72% versus 64%; 95% CI, 53% to 73%, respectively). In addition, there was no statistically significant difference in the probability of PFS over 5 years between treatment groups in patients with NHL (50%; 95% CI, 44% to 67% for plerixafor versus 43%; 95% CI, 31% to 54% for placebo) or those with MM (17%; 95% CI, 10% to 24% for plerixafor versus 30%; 95% CI, 21% to 40% for placebo). In this long-term follow-up study, the addition of plerixafor to G-CSF for stem cell mobilization did not affect 5-year survival in patients with NHL or patients with MM.

Plerixafor mobilization of peripheral blood hematopoietic progenitors to support further high-dose chemotherapy cycles in a patient with germ-cell tumor relapsing after previous tandem high-dose chemotherapy and hematopoietic cell transplantation: report of a case

Salvage high-dose chemotherapy (HDC) and autologous hematopoietic stem cell (HSC) transplantation represents a curative treatment option for patients with relapsed/refractory germ-cell tumors (GCTs). However, an appreciable proportion of these fail to mobilize adequate numbers of hematopoietic progenitors; thus, plerixafor is applied for that purpose. Limited data exist on remobilization of HSCs after previous autografting. Here, we report a unique case that had undergone successful previous tandem HDC for relapsed GCT, and 1 year later required remobilization of HSCs to support two further cycles of HDC after subsequent multiple relapses and refractoriness requiring various salvage regimens. Plerixafor in combination with granulocyte-colony stimulating factor showed its efficacy in mobilizing 6×10 CD34+/kg HSCs able to rescue two HDC cycles of carboplatin-etoposide, leading to stable hematopoietic engraftment. Plerixafor showed its potency to mobilize adequate numbers of HSCs in a patient with relapsed/refractory GCT after previous tandem HDC and autografting. The case is discussed in the context of HSC mobilization in patients who have undergone previous HDC and autografting and are deemed to have poor hematopoietic reserves, and a detailed literature review of this topic is provided.

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.

Plerixafor for autologous stem-cell mobilization and transplantation for patients in Ontario

BACKGROUND

High-dose chemotherapy with autologous stem-cell transplantation (asct) is an accepted part of standard therapy for patients with hematologic malignancies. Usually, stem-cell mobilization uses granulocyte colony-stimulating factor (g-csf); however, some patients are not able to be mobilized with chemotherapy and g-csf, and such patients could be at higher risk of failing mobilization. Plerixafor is a novel mobilization agent that is absorbed quickly after subcutaneous injection and, at the recommended dose of 0.24 mg/kg, provides a sustained increase in circulating CD34+ cells for 10-18 hours. The main purpose of the present report was to evaluate the most current evidence on the efficacy of plerixafor in enhancing hematopoietic stem-cell mobilization and collection before asct for patients in Ontario so as to make recommendations for clinical practice and to assist Cancer Care Ontario in decision-making with respect to this intervention.

METHODS

The medline and embase databases were systematically searched for evidence from January 1996 to March 2015, and the best available evidence was used to draft recommendations relevant to the efficacy of plerixafor in enhancing hematopoietic stem-cell mobilization and collection before asct. Final approval of this practice guideline report was obtained from both the Stem Cell Transplant Steering Committee and the Report Approval Panel of the Program in Evidence-Based Care.

RECOMMENDATIONS

These recommendations apply to adult patients considered for asct: ■ Adding plerixafor to g-csf is an option for initial mobilization in patients with non-Hodgkin lymphoma or multiple myeloma who are eligible for asct when chemotherapy cannot be used and only g-csf mobilization is available.■ For patients with a low peripheral blood CD34+ cell count (for example, <10/μL) at the time of anticipated stem-cell harvesting, or with an inadequate first-day apheresis collection, it is recommended that plerixafor be added to the mobilization regimen to maximize stem-cell collection and to prevent the need for remobilization.■ It is recommended that patients who have failed a previous mobilization attempt undergo remobilization with g-csf and plerixafor, with or without chemotherapy.

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.

A plerixafor-based strategy allows adequate hematopoietic stem cell collection in poor mobilizers: results from the Canadian Special Access Program

Plerixafor effectively mobilizes hematopoietic stem cells (HSCs). However, most patients' cells are successfully collected using traditional strategies and there is limited cost-effectiveness data. The objectives of this study were to: (1) summarize the published reports of mobilization using a plerixafor-based strategy during compassionate access programs and (2) describe the Canadian experience with plerixafor during its availability by Health Canada's Special Access Program. A literature search identified reports of plerixafor-based mobilization during compassionate access programs. Overall, successful collection of at least 2 × 10(6) CD34+ cells/kg was achieved in ~75% of patients, and about two-thirds of patients went on to HSCT. A greater proportion of patients had successful collections when plerixafor was used in the upfront or preemptive settings. Plerixafor was made available by Health Canada's SAP from September 2008 to December 2010. In 96 of 132 (73%) patients, there was successful collection of at least 2 × 10(6) CD34+ cells/kg. Ninety-nine (75%) patients went on to receive an autologous transplant. Plerixafor-based mobilization is effective in perceived poor mobilizers. The optimal way to incorporate plerixafor into a mobilization strategy, however, remains to be determined. Centre-specific analysis of resource utilization may help to identify the most cost-effective way to implement various plerixafor-based mobilization strategies.

Factors affecting successful mobilization with plerixafor: an Italian prospective survey in 215 patients with multiple myeloma and lymphoma

BACKGROUND

Although the efficacy of plerixafor in peripheral blood stem cell (PBSC) mobilization has been explored in several studies, factors associated with successful plerixafor mobilization after administration of granulocyte-colony-stimulating factor (G-CSF), with or without chemotherapy, have not been investigated. We analyzed data on PBSC mobilization from a large Italian database of lymphoma and myeloma plerixafor-treated patients.

STUDY DESIGN AND METHODS

Two endpoints were established to define successful mobilization: patients with at least 2 × 10(6) CD34+ cells/kg collected by three leukapheresis procedures and patients achieving a peak count of at least 20 × 10(6) CD34+ cells/L during mobilization.

RESULTS

Plerixafor achieved successful mobilization in both predicted (n = 64) and proven poor mobilizers (PMs; n = 143), classified according to the Gruppo Italiano Trapianto di Midollo Osseo (GITMO) criteria. Successful mobilization was independent of type of mobilization (steady state or chemotherapy); age; sex; disease; number or type of chemotherapy regimens preceding plerixafor; radiation therapy; prior treatment with melphalan, carmustine, lenalidomide, and radioimmune conjugates; and laboratory variables. Multivariate analysis identified previous fludarabine treatment and premobilization platelet count as predictors of successful mobilization.

CONCLUSION

This large, prospective, nationwide study confirmed plerixafor efficacy for mobilizing PBSCs when added to G-CSF with or without chemotherapy. Plerixafor can overcome negative effects of most predictors of poor mobilization to achieve satisfactory harvest both in predicted and proven PM.

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.

Predictive factors for poor peripheral blood stem cell mobilization and peak CD34(+) cell count to guide pre-emptive or immediate rescue mobilization

BACKGROUND AIMS

Failure in mobilization of peripheral blood (PB) stem cells is a frequent reason for not performing hematopoietic stem cell transplantation (HSCT). Early identification of poor mobilizers could avoid repeated attempts at mobilization, with the administration of pre-emptive rescue mobilization.

METHODS

Data from the first mobilization schedule of 397 patients referred consecutively for autologous HSCT between 2000 and 2010 were collected. Poor mobilization was defined as the collection of < 2 × 10(6) CD34(+)cells/kg body weight (BW).

RESULTS

The median age was 53 years (range 4-70) and 228 (57%) were males. Diagnoses were multiple myeloma in 133 cases, non-Hodgkin's lymphoma in 114, acute myeloid leukemia or myelodysplastic syndrome in 81, Hodgkin's lymphoma in 42, solid tumors in 17 and acute lymphoblastic leukemia in 10. The mobilization regimen consisted of recombinant human granulocyte-colony-stimulating factor (G-CSF) in 346 patients (87%) and chemotherapy followed by G-CSF (C + G-CSF) in 51 (13%). Poor mobilization occurred in 105 patients (29%), without differences according to mobilization schedule. Diagnosis, previous therapy with purine analogs and three or more previous chemotherapy lines were predictive factors for poor mobilization. A CD34(+)cell count in PB > 13.8/μL was enough to ensure ≥ 2 × 10(6) CD34(+)cells/kg, with high sensitivity (90%) and specificity (91%).

CONCLUSIONS

The prevalence of poor mobilization was high, being associated with disease type, therapy with purine analogs and multiple chemotherapy regimens. The threshold of CD34(+) cell count in PB identified poor mobilizers, in whom the administration of immediate or pre-emptive plerixafor could be useful to avoid a second mobilization.

Novel strategies for blood stem cell mobilization: special focus on plerixafor

INTRODUCTION

More than 98% of autologous stem cell transplants are now performed with the support of mobilized blood stem cells, and the proportion of allogeneic blood stem cell transplants has risen to more than 70%. Blood stem cell mobilization strategies are therefore important components of all transplant programs.

AREAS COVERED

Stem cell mobilization strategies are evaluated based on current literature, with special focus on the use of plerixafor, a CXCR4 chemokine receptor antagonist. Mobilization methods in autologous settings include the use of G-CSF alone or following chemotherapy (chemomobilization), and the use of G-CSF alone in allogeneic transplants. A combination of G-CSF + plerixafor has been shown to be effective in patients who have failed a previous mobilization. This combination has also been found to be superior to G-CSF alone in Phase III studies in myeloma and non-Hodgkin lymphoma patients as the first-line mobilization.

EXPERT OPINION

Addition of plerixafor to chemomobilization or G-CSF mobilization may be more cost-effective than its routine use, and it is worth considering in predicted or proven poor mobilizers. Novel mobilization strategies have allowed more successful stem cell collection in autologous setting, although the effect of plerixafor on graft content and long-term patient outcomes needs further investigation.