Poor mobilization is an independent prognostic factor in patients with malignant lymphomas treated by peripheral blood stem cell transplantation

Efficacy and safety of stem cell mobilization with etoposide +cytarabine plus G-CSF in poor mobilizers with relapsed or refractory lymphoma

Background

Autologous stem cell transplantation (ASCT) is a potentially curative strategy for relapse or refractory(r/r) aggressive lymphoma. However, a proportion of lymphoma patients who are at high risk of mobilization failure fail to mobilize stem cells and cannot proceed to ASCT. The aim of this study is to explore the efficacy and safety of Etoposide combined with Cytarabine (EA) plus G-CSF mobilization in poor mobilizers (PMs) with r/r aggressive lymphoma.

Methods

This retrospective study analyzed the outcomes of chemo-mobilization based on EA (Etoposide 0.1 g/m2, qd d1~3; AraC 0.5 g/m2, q12h d1~3) in 98 patients with r/r aggressive lymphoma. Of these, 39 patients met the criteria for predicted PMs as proposed by the Gruppo Italiano Trapianto di Midollo Osseo working group.

Results

Of the 39 PMs, 38(97.4%) patents harvested adequate mobilization (≥2×106 CD34+ cells/kg), while 31(79.5%) patients achieved optimal mobilization (≥5×106 CD34+ cells/kg). Overall, the mean number of CD34+ cells/kg collected was 17.99(range: 1.08~83.07) ×106 with an average of 1.4 apheresis sessions, and the number was 15.86(range: 0.37~83.07) ×106 for the first apheresis, respectively. A single apheresis procedure was sufficient to reach the target yield of adequate mobilization in 35(89.7%) PMs, while 76.9% of PMs achieved optimal collection within two apheresis sessions. We observed acceptable hematological toxicity and antibiotic usage exposure in 26 patients with a mean duration of 3.6 days. No grade 4 infection or mobilization-related mortality was recorded. Most patients underwent ASCT and achieved successful hematopoietic recovery with prompt engraftment duration, except for one NK/T-cell lymphoma patient who succumbed to severe septicemia after receiving conditioning chemotherapy.

Conclusion

Our findings indicate that EA plus G-CSF is an effective and tolerable CD34+ stem cell mobilization strategy for patients with r/r lymphoma, including those predicted to be PMs. This regimen could be an option for patients with r/r lymphoma, particularly those undergoing mobilization for salvage ASCT therapy.

Poor Mobilization-Associated Factors in Autologous Hematopoietic Stem Cell Harvest

Peripheral blood stem cell transplantation (PBSCT) is an important therapeutic measure for both hematologic and non-hematologic diseases. For PBSCT to be successful, sufficient CD34+ cells need to be mobilized and harvested. Although risk factors associated with poor mobilization in patients with hematologic diseases have been reported, studies of patients with non-hematologic diseases and those receiving plerixafor are rare. To identify factors associated with poor mobilization, data from autologous PBSC harvest (PBSCH) in 491 patients were retrospectively collected and analyzed. A multivariate analysis revealed that in patients with a hematologic disease, an age older than 60 years (odds ratio [OR] 1.655, 95% confidence interval [CI] 1.049-2.611, p = 0.008), the use of myelotoxic agents (OR 4.384, 95% CI 2.681-7.168, p < 0.001), and a low platelet count (OR 2.106, 95% CI 1.205-3.682, p = 0.009) were associated with poor mobilization. In patients with non-hematologic diseases, a history of radiation on the pelvis/spine was the sole associated factor (OR 12.200, 95% CI 1.934-76.956, p = 0.008). Among the group of patients who received plerixafor, poor mobilization was observed in 19 patients (19/134, 14.2%) and a difference in the mobilization regimen was noted among the good mobilization group. These results show that the risk factors for poor mobilization in patients with non-hematologic diseases and those receiving plerixafor differ from those in patients with hematologic diseases; as such, non-hematologic patients require special consideration to enable successful PBSCH.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Lactate dehydrogenase as a hematopoietic stem cell mobilization biomarker in autologous transplantation

INTRODUCTION

Pre-apheresis peripheral blood CD34+ cell count (PBCD34+) is the most important predictor of good cell mobilization before hematopoietic stem cell transplantation, albeit flow cytometry is not always immediately available. Identification of surrogate markers can be useful. The CD34+ cells proliferate after mobilization, resulting in elevated lactate dehydrogenase (LDH) activity and correlating with the PBCD34+ count.

OBJECTIVE

To determine the LDH cut-off value at which adequate CD34+ cell mobilization is achieved and its diagnostic yield.

MATERIALS AND METHODS

A total of 103 patients who received an autologous stem cell transplantation (ASCT) between January 2015 and January 2020 were included. Demographic and laboratory characteristics were obtained, including complete blood count, pre-apheresis PBCD34+ and LDH levels. Receiver operating characteristic (ROC) curves were performed to identify the optimal serum LDH activity cut-off points for ≥ 2 and ≥ 4 × 106 cells/kg post-mobilization CD34+ count and their diagnostic yield.

RESULTS

A post-mobilization serum LDH cut-off value of 462 U/L yielded a sensitivity (Se) = 86.8% (positive predictive value [PPV] = 72.7%), a pre- and post-mobilization serum LDH difference cut-off value of 387 U/L, an Se = 45.7% (PPV = 97%) and an LDH ratio of 2.46, with an Se = 47.1% (PPV = 97%) for an optimal mobilization count (CD34+ ≥ 4 × 106).

CONCLUSION

The LDH measurement represents a fast and affordable way to predict PBCD34+ mobilization in cases where flow cytometry is not immediately available. According to the LDH diagnostic yield, it could be used as a surrogate marker in transplant centers, supporting the CD34+ count, which remains the gold standard.

Graft conditioning with fluticasone propionate reduces graft-versus-host disease upon allogeneic hematopoietic cell transplantation in mice

Hematopoietic cell transplantation (HCT) treats many blood conditions but remains underused due to complications such as graft-versus-host disease (GvHD). In GvHD, donor immune cells attack the patient, requiring powerful immunosuppressive drugs like glucocorticoids (GCs) to prevent death. In this study, we tested the hypothesis that donor cell conditioning with the glucocorticoid fluticasone propionate (FLU) prior to transplantation could increase hematopoietic stem cell (HSC) engraftment and reduce GvHD. Murine HSCs treated with FLU had increased HSC engraftment and reduced severity and incidence of GvHD after transplantation into allogeneic hosts. While most T cells died upon FLU treatment, donor T cells repopulated in the hosts and appeared less inflammatory and alloreactive. Regulatory T cells (Tregs) are immunomodulatory and survived FLU treatment, resulting in an increased ratio of Tregs to conventional T cells. Our results implicate an important role for Tregs in maintaining allogeneic tolerance in FLU-treated grafts and suggest a therapeutic strategy of pre-treating donor cells (and not the patients directly) with GCs to simultaneously enhance engraftment and reduce GvHD upon allogeneic HCT.

Effect of Autograft CD34+ Dose on Outcome in Pediatric Patients Undergoing Autologous Hematopoietic Stem Cell Transplant for Central Nervous System Tumors

Consolidation with autologous hematopoietic stem cell transplantation (HSCT) has improved survival for patients with central nervous system tumors (CNSTs). The impact of the autologous graft CD34+ dose on patient outcomes is unknown. We wanted to analyze the relationship between CD34+ dose, total nucleated cell (TNC) dose, and clinical outcomes, including overall survival (OS), progression-free survival (PFS), relapse, non-relapse mortality (NRM), endothelial-injury complications (EIC), and time to neutrophil engraftment in children undergoing autologous HSCT for CNSTs. A retrospective analysis of the CIBMTR database was performed. Children aged <10 years who underwent autologous HSCT between 2008 to 2018 for an indication of CNST were included. An optimal cut point was identified for patient age, CD34+ cell dose, and TNC, using the maximum likelihood method and PFS as an endpoint. Univariable analysis for PFS, OS, and relapse was described using the Kaplan-Meier estimator. Cox models were fitted for PFS and OS outcomes. Cause-specific hazards models were fitted for relapse and NRM. One hundred fifteen patients met the inclusion criteria. A statistically significant association was identified between autograft CD34+ content and clinical outcomes. Children receiving >3.6×106/kg CD34+ cells experienced superior PFS (p = .04) and OS (p = .04) compared to children receiving ≤3.6 × 106/kg. Relapse rates were lower in patients receiving >3.6 × 106/kg CD34+ cells (p = .05). Higher CD34+ doses were not associated with increased NRM (p = .59). Stratification of CD34+ dose by quartile did not reveal any statistically significant differences between quartiles for 3-year PFS (p = .66), OS (p = .29), risk of relapse (p = .57), or EIC (p = .87). There were no significant differences in patient outcomes based on TNC, and those receiving a TNC >4.4 × 108/kg did not experience superior PFS (p = .26), superior OS (p = .14), reduced risk of relapse (p = .37), or reduced NRM (p = .25). Children with medulloblastoma had superior PFS (p < .001), OS (p = .01), and relapse rates (p = .001) compared to those with other CNS tumor types. Median time to neutrophil engraftment was 10 days versus 12 days in the highest and lowest infused CD34+ quartiles, respectively. For children undergoing autologous HSCT for CNSTs, increasing CD34+ cell dose was associated with significantly improved OS and PFS, and lower relapse rates, without increased NRM or EICs.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Poor Mobilizers in Lymphoma but Not Myeloma Patients Had Significantly Poorer Progression-Free Survival after Autologous Stem Cell Transplantation: Results of a Large Retrospective, Single-Center Observational Study

In our single-center study, 357 myeloma and lymphoma patients between 2009 and 2019 were mobilized with granulocyte colony-stimulating factor (G-CSF 7.5 µg/kg bid for four days) plus a fixed dose of 24 mg Plerixafor when indicated (Plerixafor Group, n = 187) or G-CSF alone (G-CSF Group, n = 170). The target CD34 cell yields were ≥2.0 × 10⁶ CD34+ cells/kg in lymphoma and ≥4.0 × 10⁶ CD34+ cells/kg in myeloma patients to enable putative second transplants in the latter. There were no significant differences in engraftment kinetics or transfusion requirements between the Plerixafor Group and the control group in the myeloma cohort, with lymphoma patients not requiring Plerixafor showing significantly faster neutrophil recovery, a trend to faster platelet recovery, and a significantly lower need for platelet transfusions, probably due to the significantly lower number of CD34-positive cells re-transfused. While in myeloma patients the outcome (overall survival, progression-free survival) following autologous stem cell transplantation (ASCT) was similar between the Plerixafor Group and the control group, hard to mobilize lymphoma patients had significantly poorer progression-free survival (47% vs. 74% at 36 months after ASCT, p = 0.003) with a trend also to poorer overall survival (71% vs. 84%). In conclusion, while there seem to be no differences in stemness capacity and long-term engraftment efficiency between the Plerixafor and the G-CSF Group in lymphoma as well as myeloma patients, poor mobilizing lymphoma patients per se constitute a high-risk population with a poorer outcome after ASCT. Whether disease characteristics and/or a more intense or stem cell-toxic pre-mobilization chemo-/radiotherapy burden in this cohort are responsible for this observation remains to be shown in future studies.

Analysis of stem cell collections in adult patients with Ewing sarcoma

BACKGROUND

Ewing sarcoma is one of the most frequent soft-tissue tumors in pediatric patients. The current treatment protocols recommend stem cell apheresis (SCA) after completion of the second course of induction therapy with vincristine, ifosfamide, doxorubicine, and etoposide (VIDE). The feasibility of SCA and graft compositions in adult patients with Ewing sarcoma have not been previously analyzed.

METHODS AND MATERIALS

The authors analyzed 29 stem cell collections of 19 adult patients (9 male, 10 female) at a median age of 27 (range 19-53) years mobilized after VIDE (n = 17), cyclophosphamide/topotecan (n = 1) or vincristine, dactinomycin and ifosfamide (n = 1) chemotherapy. All patients were mobilized with filgrastim 5 μg/kg twice daily from day +7 of chemotherapy. The collections were performed if CD34+ cell count in peripheral blood was >10/μL. The target yields were ≥4×10⁶ CD34+ cells/kg body weight.

RESULTS

Median CD34+ cells/μL in peripheral blood before SCA were 45.8 (range 6.7-614.4)/μL. The median cumulative yields were 10.6 (range 1.5-38.8) CD34+ cells/kg body weight and ≥2×10⁶ in all but two patients (89%). CD34, CD3, and CD56 yields in collections after the third VIDE and after later courses did not differ. Four patients underwent high-dose therapy with autologous transplantation, and all were engrafted.

DISCUSSION

Stem cell mobilization is feasible in most Ewing sarcoma patients. Additionally, the present study's data suggest that it is safe to postpone stem cell collection to a later VIDE chemotherapy cycle if medically indicated.

Single-center results reporting improved hematopoietic stem cell mobilization success in pediatric and young adult patients with solid tumors and lymphoma

BACKGROUND

High-dose chemotherapy with autologous hematopoietic stem cell transplantation (auto-HSCT) is an established treatment for pediatric and young adult patients with solid tumors and lymphomas. Plerixafor is a CXC chemokine receptor type 4 (CXCR4) antagonist that can be used with granulocyte colony stimulating factor (G-CSF) to amplify the mobilization of hematopoietic stem cells (HSCs).

METHODS

We performed a retrospective analysis of 167 pediatric solid tumor and lymphoma patients from January 2010 to July 2020 in whom HSCs were mobilized using G-CSF alone or with plerixafor.

RESULTS

Thirteen heavily pretreated patients (33.3%) required twice-daily dosing of G-CSF compared to five patients (3.9%) in the not heavily pretreated group (p = .0005). Fourteen heavily pretreated patients (35.9%) required plerixafor compared to four patients (3.1%) in the comparison cohort (p = .0002). The number of mobilization days was similar between both cohorts, with 5 days (range 3-11 days) in the heavily pretreated group and 5 days (range 3-13 days) in the not heavily pretreated group (p = .55). The number of harvest days was 2 days (range 1-5 days) in the heavily pretreated group and 1 day (range 1-4 days) in the not heavily pretreated group (p = .0025). The final cluster of differentiation (CD)34⁺ /kilogram (kg) count was 9.52 × 10⁶ /kg among heavily pretreated patients compared to 34.99 × 10⁶ /kg CD34⁺ cells in the comparison group (p < .0001). Three heavily pretreated patients (7.7%) failed HSC mobilization.

CONCLUSIONS

Patients at the highest risk for poor HSC mobilization can be successfully treated with more frequent G-CSF dosing or G-CSF with plerixafor in a large majority of cases.

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

Background

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

Objective

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

Patients and Methods

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

Results

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

Conclusions

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

Supplementary Information

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

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

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

Race/ethnicity and underlying disease influences hematopoietic stem/progenitor cell mobilization response: A single center experience

BACKGROUND

Whether race/ethnicity plays a role in hematopoietic stem/progenitor cells (HSPC) mobilization in autologous donors has not been studied. We hypothesize that donor characteristic including race/ethnicity, age, sex, body mass index, and diagnostic groups influences HSPC mobilization. Diagnostic groups include healthy allogeneic donors, autologous multiple myeloma (MM) and non-MM donors.

STUDY DESIGN AND METHODS

Here, we conducted a single-center retrospective study in 64 autologous patients and 48 allogeneic donors. Autologous donors were patients diagnosed with MM or non-MM. All donors were grouped as African American (AA), White (W), or "Other"(O).

RESULTS

Multivariate analysis demonstrated diagnostic group differences for CD34+ cell yields between race/ethnicity. Specifically, non-MM patients had the lowest CD34+ cell yields in AA and O, but not in W. For pre-apheresis peripheral blood (PB) CD34+ cell numbers, race/ethnicity had a significant effect both in bivariate and multivariate analyses. Non-MM patients had the lowest, and AA patients had the highest PB CD34+ cells. The results support the view that past therapies used in MM are likely more conducive of recovery of HSPC.

CONCLUSIONS

Our study shows that race/ethnicity and diagnostic group differences influenced CD34+ cell mobilization response across donor types. Interestingly, autologous MM donors with the aid of plerixafor displayed comparable CD34 yields to allogeneic donors. Even though both MM and non-MM donors received plerixafor, non-MM donors had significantly lower CD34 yields among AA and O donors but not in W donors. Larger studies would be required to validate the role of diagnostic groups and race/ethnicity interactions.

Is absence of CD56 a predictive factor for peripheral blood stem cell mobilization failure in patients with multiple myeloma?

BACKGROUND

CD56 is believed to play a major role in MM pathogenesis with a 70% to 80% expression rate in malignant plasma cells at the time of diagnosis. Our objective in this study was to investigate the relationship between the characteristics of CD56 expression in bone marrow aspiration material at the time of diagnosis and the success of stem cell mobilization in patients diagnosed with MM.

METHODS

This monocenter study included 94 patients who were diagnosed with MM and had a stem cell mobilization procedure for autologous hematopoietic stem cell transplantation. The primary endpoint of the study was to compare the mobilization success between the groups with and without CD56 expression. The secondary endpoint was to identify other factors affecting mobilization failure outside CD56.

RESULTS

At the time of diagnosis, 49 (52.1%) patients had CD56 expression and 45 (47.9%) did not. Mobilization failed in 11 (11.7%) patients. Age, gender, ISS stage and the number of premobilization treatment regimens were not found predictive of mobilization failure. CD56 negativity was 42.2% in the group that had mobilization success and 90.9% in the group that had mobilization failure (P = .001).

CONCLUSIONS

The fact that CD56 residing on the membrane enables interaction between bone marrow cells and ECM and functions as a signal molecule increases sensitivity to the chemotherapy and G-CSF that are used for mobilization. We found that absence of CD56 can be used as a predictive factor for mobilization failure at the time of diagnosis.

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

BACKGROUND

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

STUDY DESIGN AND METHODS

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

RESULTS

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

CONCLUSION

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

CD34+ cell mobilization, blood graft composition, and posttransplant recovery in myeloma patients compared to non-Hodgkin's lymphoma patients: results of the prospective multicenter GOA study

BACKGROUND

Autologous stem cell transplantation is an established treatment option for patients with multiple myeloma (MM) or non-Hodgkin's lymphoma (NHL).

STUDY DESIGN AND METHODS

In this prospective multicenter study, 147 patients with MM were compared with 136 patients with NHL regarding the mobilization and apheresis of blood CD34+ cells, cellular composition of infused blood grafts, posttransplant recovery, and outcome.

RESULTS

Multiple myeloma patients mobilized CD34+ cells more effectively (6.3 × 10⁶ /kg vs. 3.9 × 10⁶ /kg, p = 0.001). The proportion of poor mobilizers (peak blood CD34+ cell count <20 × 10⁶ /L) was higher in NHL patients (15% vs. 3%, p < 0.001). Plerixafor was added to rescue the mobilization failure in 17 MM patients (12%) and in 35 NHL patients (26%; p = 0.002). The infused grafts contained more natural killer (NK) and CD19+ cells in MM patients. Blood platelet and NK-cell counts were higher in MM patients posttransplant. Early treatment-related mortality was low in both groups, but NHL patients had a higher late (>100 days) nonrelapse mortality (NRM; 6% vs. 0%, p = 0.003).

CONCLUSIONS

Non-Hodgkin's lymphoma and MM patients differ in terms of mobilization of CD34+ cells, graft cellular composition, and posttransplant recovery. Thus, the optimal graft characteristics may also be different.

Evolution of Peripheral Blood Stem Cell Transplantation

Blood-derived progenitors have become the predominant source of hematopoietic stem cells for clinical transplantation. The main advantages compared to the bone marrow are as follows: harvesting blood stem cells is less painful for the donor, utilizes much less resources such as operating theater time and general anesthesia, and, above all, is associated with significantly accelerated reconstitution. The latter has ultimately improved patient safety as a consequence of significantly shortened aplastic phase and hence reduced morbidity and mortality after transplantation. Basic and translational research efforts in the 1960s to the mid-1980s have made the first blood stem cell transplantation in Heidelberg in 1985 possible. Diverse groups around the world have contributed to incremental knowledge that culminated in the first successful attempts in blood stem cell transplantation. These efforts have spawned modern research into stem cell biology and the immune modulatory effects of allogeneic transplantations.

Optimized peripheral blood progenitor cell mobilization for autologous hematopoietic cell transplantation in children with high-risk and refractory malignancies

BACKGROUND

Autologous hematopoietic stem cell transplantation (aHSCT) using hematopoietic progenitor cells (HPCs) has become an important therapeutic modality for patients with high-risk malignancies. Current literature on standardized method for HPC apheresis in children is sparse and failure rate reported as high as 30%.

PATIENTS/METHODS

A retrospective study of 125 pediatric patients with high-risk malignancies undergoing aHSCT in Western Australia between 1997 and 2016 was conducted.

RESULTS

Mobilization was achieved by means of chemotherapy and granulocyte colony-stimulating factor (G-CSF). Patients underwent apheresis the day after CD34⁺ counts reached ≥20/µL and an additional dose of G-CSF. Peripheral arterial and intravenous lines were inserted in pediatric intensive care unit under local anesthetic and/or sedation, omitting the need for general anesthesia as well as facilitating an uninterrupted apheresis flow. Larger apheresis total blood volumes were processed in patients weighing ≤20 kg. The minimal dose of ≥2 × 10⁶ CD34⁺ cells/kg was successfully collected in 98.4% of all patients. The optimal dose of 3-5 × 10⁶ CD34⁺ cells/kg was collected in 96% of patients scheduled for a single aHSCT, 87.5% for tandem, and 100% for triple aHSCT. All HPC collections were completed in one apheresis session. Mobilization after ≤3 chemotherapy cycles and cycles including cyclophosphamide resulted in a significantly higher yield of CD34⁺ cells.

CONCLUSION

Our approach to HPC mobilization by means of chemotherapy and single myeloid growth factor combined with optimal collection timing facilitated by continuous apheresis flow resulted in highly effective HPC harvest in children and adolescents with high-risk cancers.

Analysis of data collected in the European Society for Blood and Marrow Transplantation (EBMT) Registry on a cohort of lymphoma patients receiving plerixafor

Plerixafor + granulocyte-colony stimulating factor (G-CSF) is administered to patients with lymphoma who are poor mobilizers of hematopoietic stem cells (HSCs) in Europe. This international, multicenter, non-interventional registry study (NCT01362972) evaluated long-term follow-up of patients with lymphoma who received plerixafor for HSC mobilization versus other mobilization methods. Propensity score matching was conducted to balance baseline characteristics between comparison groups. The following mobilization regimens were compared: G-CSF + plerixafor (G + P) versus G-CSF alone; G + P versus G-CSF + chemotherapy (G + C); and G-CSF + plerixafor + chemotherapy (G + P + C) versus G + C. The primary outcomes were progression-free survival (PFS), overall survival (OS), and cumulative incidence of relapse (CIR). Overall, 313/3749 (8.3%) eligible patients were mobilized with plerixafor-containing regimens. After propensity score matching, 70 versus 36 patients were matched in the G + P versus G-CSF alone cohort, 124 versus 124 in the G + P versus G + C cohort, and 130 versus 130 in the G + P + C versus G + C cohort. For both PFS and OS, the upper bound of confidence interval for the hazard ratio was >1.3 for all comparisons, implying that non-inferiority was not demonstrated. No major differences in PFS, OS, and CIR were observed between the plerixafor and comparison groups.

The effect of the dexamethasone, cytarabine, and cisplatin (DHAP) regimen on stem cell mobilization and transplant outcomes of patients with non-Hodgkin's lymphoma who are candidates for up-front autologous stem cell transplantation

BACKGROUND/AIMS

Data on dexamethasone, cytarabine, and cisplatin (DHAP) as a mobilization regimen, compared to high-dose cyclophosphamide (HDC), for up-front autologous stem cell transplantation (ASCT) in non-Hodgkin's lymphoma (NHL) is limited.

METHODS

Consecutive patients with aggressive NHL treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or rituximab-CHOP who underwent chemomobilization using HDC or DHAP plus granulocyte-colony stimulating factor (G-CSF) for up-front ASCT were enrolled from three institutions between 2004 and 2014.

RESULTS

Ninety-six patients (57 men) were included. Sixty-five patients (67.7%) received HDC; and 31 (32.3%), DHAP. The total CD34+ cells mobilized were significantly higher in patients receiving DHAP (16.1 vs. 6.1 × 106/kg, p = 0.001). More patients achieved successful mobilization with DHAP (CD34+ cells ≥ 5.0 × 106/kg) compared to HDC (87.1% vs. 61.5%, respectively; p = 0.011), particularly within the first two sessions of apheresis (64.5% vs. 32.3%, respectively; p = 0.003). Mobilization failure rate (CD34+ cells < 2.0 × 106/kg) was significantly higher in patients receiving HDC (20.0% vs. 3.2%, p = 0.032). On multivariate analysis, the DHAP regimen (odds ratio, 4.12; 95% confidence interval, 1.12 to 15.17) was an independent predictor of successful mobilization. During chemomobilization, patients receiving HDC experienced more episodes of febrile neutropenia compared to patients receiving DHAP (32.3% vs. 12.9%, p = 0.043).

CONCLUSION

The DHAP regimen was associated with a significantly higher efficacy for stem cell mobilization and lower frequency of febrile neutropenia. Therefore, DHAP plus G-CSF is an effective for mobilization in patients with aggressive NHL who were candidates for up-front ASCT.

Poor mobilizer and its countermeasures

Mobilization failure is a major concern in patients undergoing hematopoietic cell transplantation, especially in an autologous setting, as almost all donor harvests can be accomplished with granulocyte-colony stimulating factor (G-CSF) alone. Poor mobilizers, defined as those with a peripheral blood CD34⁺ cell count ≤20 cells/μl after mobilization preceding apheresis is a significant risk factor for mobilization failure. We recommend preemptive plerixafor plus G-CSF (filgrastim, 10 μg/kg daily) as a first mobilization strategy, which yields sufficient peripheral blood progenitor cells (PBPCs) in almost all patients and avoids otherwise unnecessary remobilization. Preemptive plerixafor is administered in patients with a day-4 peripheral blood CD34⁺ count <15, depending on the disease and the target PBPC amount. Cyclophosphamide is reserved for patients who fail the first PBPC collection. We recommend second mobilization for patients who could not achieve a sufficient PBPC amount with the first mobilization. In these patients, a second attempt with plerixafor plus G-CSF or mobilization with plerixafor in combination with cyclophosphamide and G-CSF is recommended. Increased dose and/or twice daily administration of G-CSF can be considered.

Plerixafor in non-Hodgkin's lymphoma patients: a German analysis of time, effort and costs

Mobilization and collection of peripheral blood stem cells is part of the standard treatment procedure for non-Hodgkin’s lymphoma patients eligible for high-dose chemotherapy with autologous stem cell transplantation. Mobilization is usually achieved with chemotherapy and/or cytokines, but plerixafor might be added in case of poor mobilization. Due to the high cost several institutions have developed their own management pathway to optimize use of plerixafor. Such models are however rarely generalizable; in a multi-center, European, non-interventional study, evaluating the impact of plerixafor in poor mobilizers, country specific differences in patient treatment and cost structure were obvious. For German centers, there was a non-significant reduction in the number of apheresis sessions carried out and in apheresis costs. In contrast to other European countries the majority of German Plerixafor patients were very poor mobilizing patients with initial CD34+ cell count ≤ 10/µl (40/51). In this group the number of apheresis sessions decreased from 2.1 to 1.6 sessions per patient (p = 0.01) and costs decreased from €6246 to €4758 (p = 0.01). Our results show that preemptive plerixafor use has a strong effect in poor mobilizers with an initial CD34+ cell count ≤ 10 cells/µl.

Plerixafor in poor mobilizers with non-Hodgkin's lymphoma: a multi-center time-motion analysis

High-dose chemotherapy alongside peripheral blood stem cell (PBSC) infusion has become the standard of care in different hematologic malignancies. The goal of PBSC mobilization is to allow collection of sufficient CD34+ cells to proceed to transplantation. The current mobilization regimen with granulocyte colony-stimulating factor (G-CSF), alone or in combination with chemotherapy, still fails in 10-25% of patients. Plerixafor is able to rescue most of these patients from mobilization failure. In this study, we investigated the impact of plerixafor on the cost and time spent on apheresis in patients who were considered poor mobilizers, with <20 × 10⁶/µl peripheral CD34+ cells after mobilization but prior to apheresis. Patient hospital records from ten centers in three European countries were reviewed and compared during two time periods, namely prior and after plerixafor introduction to the market. During the plerixafor period, patients spent less time on apheresis (350 vs. 461  min). Poor mobilizers given plerixafor collected more CD34+ cells during the first apheresis session, leading to a decrease in the average number of apheresis sessions needed. The total apheresis yield was unaffected. This analysis shows that the use of plerixafor lessens the time-effort associated with the management of poor mobilizers and reduces apheresis costs.

A novel association between relaxin receptor polymorphism and hematopoietic stem cell yield after mobilization

Mobilization of hematopoietic stem cells (HSCs) from the bone marrow to the peripheral blood is a complex mechanism that involves adhesive and chemotactic interactions of HSCs as well as their bone marrow microenvironment. In addition to a number of non-genetic factors, genetic susceptibilities also contribute to the mobilization outcome. Identification of genetic factors associated with HSC yield is important to better understand the mechanism behind HSC mobilization. In the present study, we enrolled 148 Korean participants (56 healthy donors and 92 patients) undergoing HSC mobilization for allogeneic or autologous HSC transplantation. Among a total of 53 polymorphisms in 33 candidate genes, one polymorphism (rs11264422) in relaxin/insulin-like family peptide receptor 4 (RXFP4) gene was significantly associated with a higher HSC yield after mobilization in Koreans. However, in a set of 101 Europeans, no association was found between circulating CD34+ cell counts and rs11264422 genotype. Therefore, we suggest that the ethnic differences in subjects’ genetic background may be related to HSC mobilization. In conclusion, the relaxin—relaxin receptor axis may play an important role in HSC mobilization. We believe that the results of the current study could provide new insights for therapies that use relaxin and HSC populations, as well as a better understanding of HSC regulation and mobilization at the molecular level.

Identification of cell morphology parameters from automatic hematology analyzers to predict the peripheral blood CD34-positive cell count after mobilization

Optimal timing of apheresis initiation is important for maximizing the hematopoietic stem cell (HSC) yield. This study aimed to identify useful parameters from automatic hematology analyzers for predicting the peripheral blood CD34+ cell count after mobilization. We prospectively enrolled 53 healthy donors and 72 patients, and evaluated 43 cell morphology parameters from Unicel DxH800 (Beckman Coulter, USA) and Advia 2120i (Siemens Healthcare Diagnostics, USA). The correlation of each parameter with the CD34+ cell count in pre-apheresis blood samples was analyzed. The delta neutrophil index (DNI) from Advia 2120i, standard deviation of volume of neutrophils and monocytes (SD-V-NE and SD-V-MO), standard deviation of conductivity of neutrophils and monocytes (SD-C-NE and SD-C-MO), mean conductivity of neutrophils and monocytes (MN-C-NE and MN-C-MO), and standard deviation of axial light loss of neutrophils and monocytes (SD-AL2-NE and SD-AL2-MO) from DxH800 showed significant correlations with the CD34+ cell count. SD-V-NE, SD-C-NE, and SD-C-MO showed good or fair area under the curve values for the prediction of the CD34+ cell count. SD-V-NE, SD-C-NE, and SD-C-MO from DxH800 will provide rapid, useful information for the initiation of apheresis after mobilization.

Prospective noninterventional study on peripheral blood stem cell mobilization in patients with relapsed lymphomas

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) to rescue hematopoiesis is considered standard care for patients with a relapsed chemosensitive lymphoma, but diagnosis of lymphoma has been a risk factor for poor mobilization in several studies. The aim of this prospective noninterventional clinical audit was to review the mobilization strategies used by EBMT centers in relapsed lymphoma and to evaluate their efficacy. Between 2010 and 2014, 275 patients with relapsed lymphoma from 30 EBMT centers were prospectively registered. Almost all patients were mobilized with chemotherapy plus G-CSF (96%), but there was a large variation in chemotherapy schedules. Thirty (11%) of them were poor mobilizers (<2 × 10⁶ CD 34+ cells/kg body weight) at the first mobilization. Poor mobilization was not associated with gender, age, bone marrow involvement at diagnosis, primary diagnosis, number of previous chemotherapy lines, previous radiotherapy or mobilization with G-CSF alone. The use of high dose cyclophosphamide alone was associated with mobilization failure (P = 0.0006), whereas the use of a platinum-containing regimen was associated with a good mobilization outcome (P = 0.013). Because failure rate is low, we can conclude from this study that PBSC mobilization failure in relapsed lymphomas is not an important problem in the EBMT centers.

Plerixafor as preemptive strategy results in high success rates in autologous stem cell mobilization failure

Plerixafor in combination with granulocyte-colony stimulating factor (G-CSF) is approved for autologous stem cell mobilization in poor mobilizing patients with multiple myeloma or malignant lymphoma. The purpose of this study was to evaluate efficacy and safety of plerixafor in an immediate rescue approach, administrated subsequently to G-CSF alone or chemotherapy and G-CSF in patients at risk for mobilization failure. Eighty-five patients mobilized with G-CSF alone or chemotherapy were included. Primary endpoint was the efficacy of the immediate rescue approach of plerixafor to achieve ≥2.0 × 10⁶ CD34⁺ cells/kg for a single or ≥5 × 10⁶ CD34⁺ cells/kg for a double transplantation and potential differences between G-CSF and chemotherapy-based mobilization. Secondary objectives included comparison of stem cell graft composition including CD34⁺ cell and lymphocyte subsets with regard to the mobilization regimen applied. No significant adverse events were recorded. A median 3.9-fold increase in CD34⁺ cells following plerixafor was observed, resulting in 97% patients achieving at least ≥2 × 10⁶ CD34+ cells/kg. Significantly more differentiated granulocyte and monocyte forming myeloid progenitors were collected after chemomobilization whereas more CD19⁺ and natural killer cells were collected after G-CSF. Fifty-two patients underwent transplantation showing rapid and durable engraftment, irrespectively of the stem cell mobilization regimen used. The addition of plerixafor in an immediate rescue model is efficient and safe after both, G-CSF and chemomobilization and results in extremely high success rates. Whether the differences in graft composition have a clinical impact on engraftment kinetics, immunologic recovery, and graft durability have to be analysed in larger prospective studies.

Hematopoietic Progenitor Cell Mobilization with Ifosfamide, Carboplatin, and Etoposide Chemotherapy versus Plerixafor-Based Strategies in Patients with Hodgkin and Non-Hodgkin Lymphoma

Studies comparing the efficacy and safety of chemo-mobilization with ifosfamide, carboplatin, and etoposide (ICE) ± rituximab with plerixafor-based approaches in lymphoma patients have not been performed. We analyzed hematopoietic progenitor cell mobilization outcomes in lymphoma patients undergoing chemo-mobilization with ICE (n = 35) compared with either routine plerixafor (n = 30) or "just in time" (JIT) plerixafor-based mobilization (n = 33). Chemo-mobilization provided a significantly higher total CD34(+) cell yield (median collection, 5.35 × 10(6) cells/kg for ICE versus 3.15 × 10(6) cells/kg for routine plerixafor and 3.6 × 10(6) cells/kg for JIT plerixafor, P < .001). The median day 1 yield of CD34(+) cells was not significantly different (median, 2.2 × 10(6) cells/kg in ICE versus 1.9 × 10(6) cells/kg in upfront plerixafor versus 1.7 × 10(6) cells/kg in JIT plerixafor, P = .20). There was no significant difference in the 3 groups in terms of total number of apheresis sessions performed (median, 2 in each group; P = .78). There were no mobilization failures (inability to collect at least 2 × 10(6) cells/kg) in the chemo-mobilization group, whereas 5 patients (16.7%) in the routine plerixafor and 3 patients (9.1%) in JIT group had mobilization failure (P = .04). Mean time to neutrophil engraftment was faster in the chemo-mobilization group, 10.3 days (±1.2) compared with 12.1 days (±3.6) in the routine plerixafor group and 11.6 days (±3.0) in the JIT group (P < .001) and mean time to platelet engraftment was 13.7 days (±.7) in ICE versus 20.3 days (±1.6) in routine plerixafor versus 17.1 days (± .9) in JIT group (P < .001). Red blood cell transfusions were significantly higher in the chemo-mobilization group (34.3% versus 0 versus 3.2% versus 1, P < .001) and so were the platelet transfusions (22.9% versus 0 versus 0, P < .001). Excluding the cost of chemotherapy administration, chemo-mobilization was associated with significantly less mobilization cost (average cost $17,601.76 in ICE versus $28,963.05 in routine and $25,679.81 in JIT, P < .001). Our data suggests that chemo-mobilization with ICE provides a higher total CD34(+) cell yield, lower rates of mobilization failure, faster engraftment, and lower cost compared to plerixafor-based approaches with comparable toxicity profile between the groups, except for higher transfusion requirements with chemo-mobilization.

Decision-tree algorithm for optimized hematopoietic progenitor cell-based predictions in peripheral blood stem cell mobilization

BACKGROUND

Enumerating hematopoietic progenitor cells (HPCs) by using an automated hematology analyzer is a rapid, inexpensive, and simple method for predicting a successful harvest compared with enumerating circulating CD34+ cells. However, the optimal HPC cutoff count and the indicating factors to be considered for improved predicting have not yet been determined.

STUDY DESIGN AND METHODS

Between 2007 and 2012, a total of 189 consecutive patients who proceeded to peripheral blood stem cell (PBSC) harvesting were retrospectively recruited. Baseline characteristics were analyzed to identify the risk factors for a failed harvest, which were defined as less than 2 × 10(6) CD34+ cells/kg. Variables identified by multivariate logistic regression and correlation analysis for predicting a successful harvest were subjected to classification and regression tree (CART) analysis.

RESULTS

PBSCs were successfully harvested in 154 (81.5%) patients. An age of at least 60 years, a diagnosis of a solid tumor, at least five prior chemotherapy cycles, prior radiotherapy, and mobilization with granulocyte-colony-stimulating factor alone or high-dose cyclophosphamide were independent baseline predictors of poor mobilization. In CART analysis, patients with zero to two host risk factors and either higher HPC (≥28 × 10(6) /L) or mononuclear cell (MNC; ≥3.5 × 10(9) /L) counts were categorized as good mobilizers and their harvest success rate was 92.3%. By contrast, 30.3% of harvests were adequate in the patients with three to five host risk factors and lower HPC and MNC counts.

CONCLUSION

A CART algorithm incorporating host predictors and HPC and MNC counts improves predictions in a successful harvest and might reduce the necessity of monitoring peripheral CD34+ cells.

Italian consensus conference for the outpatient autologous stem cell transplantation management in multiple myeloma

Multiple myeloma (MM) is the leading indication for autologous stem cell transplantation (ASCT) worldwide. The safety and efficacy of reducing hospital stay for MM patients undergoing ASCT have been widely explored, and different outpatient models have been proposed. However, there is no agreement on the criteria for selecting patients eligible for this strategy as well as the standards for their clinical management. On the basis of this rationale, the Italian Group for Stem Cell Transplantation (GITMO) endorsed a project to develop guidelines for the management of outpatient ASCT in MM, using evidence-based knowledge and consensus-formation techniques. An expert panel convened to discuss the currently available data on the practice of outpatient ASCT management and formulated recommendations according to the supporting evidence. Evidence gaps were filled with consensus-based statements. Three main topics were addressed: (1) the identification of criteria for selecting MM patients eligible for outpatient ASCT management; (2) the definition of standard procedures for performing outpatient ASCT (model, supportive care and monitoring during the aplastic phase); (3) the definition of the standard criteria and procedures for re-hospitalization during the aplastic phase at home. Herein, we report the summary and the results of the discussion and the consensus.

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

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

Increased efficacy of intermediate-dose cytarabine + G-CSF compared to DHAP + G-CSF for stem cell mobilization in patients with lymphoma: an analysis by the polish lymphoma research group

Salvage regimens, like DHAP (dexamethasone, cytarabine, and cisplatin) are frequently used for stem cell mobilization in lymphoma. The aim of this study was to compare the efficacy of DHAP + G-CSF with intermediate-dose cytarabine (ID-AraC) + G-CSF, recently proposed as an alternative schedule. Consecutive patients with Hodgkin's or non-Hodgkin lymphoma who had received at least 2 lines of chemotherapy, mobilized with either DHAP (n = 51) or ID-AraC (n = 50) + G-CSF were included in the analysis. AraC was administered at the dose of 400 mg/m [1] bid intravenously for 2 days followed by filgrastim starting from day 5. In the AraC group, 96 % of patients collected at least 2 × 10 [2] CD34(+) cells/kg compared to 71 % in the DHAP group (p = 0.0006). The CD34(+) cell yield was 9.3 (0-30.3) × 10 [2]/kg vs. 5.6 (0-24.8) × 10 [2]/kg, respectively (p = 0.006). A single apheresis was sufficient to achieve the threshold number of CD34(+) cells in 82 % of the cases after AraC compared to 45 % after DHAP (p = 0.001). We conclude that stem cell mobilization using ID-AraC is associated with a significantly higher efficacy than DHAP, allowing for collection of the transplant material in almost all patients with lymphoma. Our observation suggests that ID-AraC + G-CSF may be a preferable mobilization regimen in this setting.

Hematopoietic progenitor cell mobilization for autologous transplantation - a literature review

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

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.

Hematopoietic Progenitor Cell Harvesting Is Feasible after Treatment with Brentuximab Vedotin in CD30(+) Lymphoma Patients Who Received Multiple Prior Lines of Treatment

Brentuximab vedotin (BV), an antibody-drug conjugate that targets CD30, induces high response rates in CD30(+) lymphoid malignancies. It is unknown if BV use affects procurement of autologous CD34(+) stem cells and hematopoietic engraftment after autologous stem cell transplantation (ASCT). We examined 42 patients treated with BV before mobilization. Median times from diagnosis to transplantation, from initial BV treatment to transplantation, and from last BV treatment to stem cell collection were 21 months (range, 10 to 210), 5 months (range, 1.5 to 16.8), and 30 days (range, 2 to 280), respectively. Mobilization was successful on the first attempt in 38 patients (90.4%). The median number of infused CD34(+) cells was 5.46 × 10(6)/kg (range, 1.65 to 54.78 × 10(6)/kg). The median times to neutrophil and platelet engraftment were 10 (range, 9 to 13), and 10.5 days (range, 7 to 35), respectively. BV before high-dose chemotherapy-ASCT did not adversely affect peripheral blood stem cell mobilization and subsequent engraftment in a cohort of heavily pretreated patients with CD30(+) lymphomas.

Concise review: Sowing the seeds of a fruitful harvest: hematopoietic stem cell mobilization

Hematopoietic stem cell transplantation is the only curative option for a number of malignant and nonmalignant diseases. As the use of hematopoietic transplant has expanded, so too has the source of stem and progenitor cells. The predominate source of stem and progenitors today, particularly in settings of autologous transplantation, is mobilized peripheral blood. This review will highlight the historical advances which led to the widespread use of peripheral blood stem cells for transplantation, with a look toward future enhancements to mobilization strategies.

Ex vivo expansion of human mobilized peripheral blood stem cells using epigenetic modifiers

BACKGROUND

Epigenetic modifications likely control the fate of hematopoietic stem cells (HSCs). The chromatin-modifying agents (CMAs), 5-aza-2'-deoxycytidine (5azaD) and trichostatin A (TSA), have previously been shown to expand HSCs from cord blood and marrow. Here we assessed whether CMA can also expand HSCs present in growth factor-mobilized human peripheral blood (MPB).

STUDY DESIGN AND METHODS

5azaD and TSA were sequentially added to CD34+ MPB cells in the presence of cytokines, and the cells were cultured for 9 days.

RESULTS

After culture, a 3.6 ± 0.5-fold expansion of CD34+CD90+ cells, a 10.1 ± 0.5-fold expansion of primitive colony-forming unit (CFU)-mix, and a 2.2 ± 0.5-fold expansion of long-term cobblestone-area-forming cells (CAFCs) was observed in 5azaD/TSA-expanded cells. By contrast, cells cultured in cytokines without 5azaD/TSA displayed no expansion; rather, a reduction in CD34+CD90+ cells (0.7 ± 0.1-fold) and CAFCs (0.3 ± 0.1-fold) from their initial numbers was observed. Global hypomethylation corresponding with increased transcript levels of several genes implicated in HSC self-renewal, including HOXB4, GATA2, and EZH2, was observed in 5azaD/TSA-expanded MPB cells in contrast to controls. 5azaD/TSA-expanded MPB cells retained in vivo hematopoietic engraftment capacity.

CONCLUSION

MPB CD34+ cells from donors can be expanded using 5azaD/TSA, and these expanded cells retain in vivo hematopoietic reconstitution capacity. This strategy may prove to be potentially useful to augment HSC numbers for patients who fail to mobilize.

The prognostic impact of peripheral blood progenitor cell dose following high-dose therapy and autologous stem cell transplant for hematologic malignancies

High-dose chemotherapy (HDT) followed by autologous peripheral blood progenitor cell transplant (PBPCT) has become a standard intervention in certain clinical settings of hematologic malignancies, particularly multiple myeloma and relapsed/refractory lymphoma. While the minimal required PBPCs infused, as defined by number of CD34 + cells, has been relatively well delineated for adequate hematopoietic recovery post-HDT, optimal PBPC dose has not been clearly defined. This is particularly relevant in the context of retrospective data suggesting improved survival outcomes with increased PBPC doses. The potential confounding of these data as they relate to disease risk is discussed within this review. Additionally, other retrospective data have suggested that enhanced quantitative lymphocyte subset reconstitution post-HDT-PBPCT may confer progression-free and overall survival advantage. These reported series herein reviewed may inform discussion of future, prospective clinical trials with the intent of defining optimal autologous PBPC dose following HDT, especially as it may relate to metrics beyond hematopoietic recovery.

Peripheral blood stem cell yield calculated using preapheresis absolute CD34+ cell count, peripheral blood volume processed, and donor body weight accurately predicts actual yield at multiple centers

BACKGROUND

Accurate prediction of stem cell yield is important for planning leukapheresis procedures. A formula has been published (Pierelli et al., Vox Sang 2006;91:126-34) to estimate the CD34+ dose collected on the first day of leukapheresis that was based on the preapheresis peripheral blood (PB) CD34+ counts, the blood volume processed, and the donor's weight. The aim of this study was to assess the predictive value of this formula.

STUDY DESIGN AND METHODS

Data were retrospectively collected on 1126 consecutive PB stem cell harvests conducted at five institutions. Information on age, sex, diagnosis, weight, preapheresis absolute peripheral CD34+ count, total blood volume processed, and CD34+ cells harvested per kilogram of body weight on the first day of apheresis was collected.

RESULTS

Among donors at least 18 years old, Pearson's correlation coefficient (r) between actual yield (AY) and predicted yield (PY) was 0.76. To characterize this correlation, AY and PY were classified as being within the conventionally acceptable CD34+ doses (>2 × 10(6) -5 × 10(6) cells/kg), below this range (≤2 × 10(6) cells/kg), or above it (>5 × 10(6) cells/kg). The positive predictive value (PPV) of PY was estimated considering the distribution of AY as the "gold standard." PPV was relatively high for PY of more than 5 × 10(6) cells/kg (85%), moderate for PY of not more than 2 × 10(6) cells/kg (72%), and low for PY more than 2 × 10(6) to 5 × 10(6) cells/kg (56%). A consistent pattern was observed within institutions.

CONCLUSION

The formula of Pierelli et al. is associated with a PPV that is high, moderate, and relatively low for the corresponding predicted CD34+ doses.

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.

Hematopoietic stem and progenitor cell mobilization in mice

Hematopoietic stem cell transplantation (HSCT) can be performed with hematopoietic stem and progenitor cells (HSPC) acquired directly from bone marrow, from umbilical cord blood or placental tissue, or from the peripheral blood after treatment of the donor with agents that enhance egress of HSPC into the circulation, a process known as "mobilization." Mobilized peripheral blood stem cells (PBSC) have become the predominate hematopoietic graft for HSCT, particularly for autologous transplants. Despite the success of PBSC transplant, many patients and donors do not achieve optimal levels of mobilization. Thus, accurate animal models and basic laboratory investigations are needed to further investigate the mechanisms that lead to PBSC mobilization and define improved or new mobilizing agents and/or strategies to enhance PBSC mobilization and transplant. This chapter outlines assays and techniques for exploration of hematopoietic mobilization using mice as a model organism.

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.

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

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