Plerixafor is superior to conventional chemotherapy for first-line stem cell mobilisation, and is effective even in heavily pretreated patients

A prospective, multicenter study on hematopoietic stemcell mobilization with cyclophosphamide plus granulocyte colony-stimulating factor and 'on-demand' plerixafor in multiple myeloma patients treated with novel agents

High-dose melphalan plus autologous stem cell transplantation (ASCT) is a standard of care for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM), and adequate hematopoietic stem cell (HSC) collection is crucial to ensure hematologic recovery after ASCT. In this prospective, observational study we evaluated HSC mobilization with granulocyte colony-stimulating factor (G-CSF), cyclophosphamide, and 'on-demand' plerixafor (in patients with <20×106 CD34+ cells/L after at least 4 days of G-CSF or failing to collect ≥1×106 CD34+ cells/kg after the first apheresis) in NDMM patients treated with novel agent-based induction therapy. The primary endpoint was the rate of poor mobilizers (patients collecting <2×106 CD34+ cells/kg or requiring plerixafor rescue to reach an adequate HSC harvest). Secondary endpoints included the rate of patients collecting ≥2×106 CD34+ cells/kg after plerixafor administration and the identification of factors predicting mobilization failure or plerixafor need. Overall, 301 patients (median age 60 years) were enrolled. Two hundred and eighty-seven of 301 (95%) and 274 of 301 (93%) patients collected ≥2×106 and ≥4×106 CD34+ cells/kg, respectively, with a median of 9.9×106 CD34+ cells/kg collected. Poor mobilizers were 48 of 301 (16%): 34 of 301 (11%) required plerixafor rescue, and 14 of 301 (5%) failed HSC collection regardless of plerixafor. Thirty-four of 38 (90%) patients receiving plerixafor collected ≥2×106 CD34+ cells/kg. Bone marrow plasmacytosis at diagnosis >60% (odds ratio [OR]=4.14), lenalidomide use (OR=4.45), and grade 3-4 hematologic toxicities during induction (OR=3.53) were independently associated with a higher risk of mobilization failure or plerixafor need. Cyclophosphamide plus G-CSF and 'on-demand' plerixafor is an effective strategy in NDMM patients treated with novel agents, resulting in a high rate of HSC collection and high HSC yield (clinicaltrials gov. identifier: NCT03406091).

Pharmacoeconomic issues in stem cell mobilization

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION

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

A Review of Advances in Hematopoietic Stem Cell Mobilization and the Potential Role of Notch2 Blockade

Hematopoietic stem cell (HSC) transplantation can be a potential cure for hematological malignancies and some nonhematologic diseases. Hematopoietic stem and progenitor cells (HSPCs) collected from peripheral blood after mobilization are the primary source to provide HSC transplantation. In most of the cases, mobilization by the cytokine granulocyte colony-stimulating factor with chemotherapy, and in some settings, with the CXC chemokine receptor type 4 antagonist plerixafor, can achieve high yield of hematopoietic progenitor cells (HPCs). However, adequate mobilization is not always successful in a significant portion of donors. Research is going on to find new agents or strategies to increase HSC mobilization. Here, we briefly review the history of HSC transplantation, current mobilization regimens, some of the novel agents that are under investigation for clinical practice, and our recent findings from animal studies regarding Notch and ligand interaction as potential targets for HSPC mobilization.

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

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

A retrospective study of autologous stem cell mobilization by G-CSF in combination with chemotherapy in patients with multiple myeloma and lymphoma

Factors affecting peripheral blood hematopoietic stem cell (PBSC) mobilization and collection were investigated in patients with multiple myeloma (MM) and lymphoma who were undergoing chemotherapy. Clinical data from 128 patients, including 53 MM and 75 malignant lymphoma (7 Hodgkin's lymphoma and 68 non-Hodgkin's lymphoma) cases were retrospectively analyzed. Autologous PBSCs were mobilized using granulocyte-colony stimulating factor (G-CSF) during chemotherapy, and collected using a continuous flow cell separation instrument. The yields of CD34+ cells per kilogram of patient body weight <2.0×10⁶/kg, >2.0×10⁶/kg or >5.0×10⁶/kg were defined as a failure, a success or ideal mobilization, respectively. In MM and lymphoma patients, the success rates of CD34+ cell acquisition were 73.6 (39/53) and 58.7% (44/75), the ideal rates were 43.4 (23/53) and 30.7% (23/75), and the failure rates were 26.4 (14/53) and 41.3% (31/75), respectively. Univariate and multivariate statistical analysis revealed that negative factors for PBSC mobilization in patients with MM were lenalidomide treatment, multiple chemotherapies, incomplete disease remission and low-level blood hemoglobin; in patients with lymphoma, the negative factors were the histological disease type, incomplete disease remission, being beyond the first-line of previous chemotherapy, multiple chemotherapies, chemotherapy with the HyperCVAD-B mobilization scheme, high-dose MTX/Ara-c (methotrexate/cytarabine) treatment, prolonged administration of G-CSF and low-hematocrit levels. In the present study, different factors influencing PBSC mobilization and collection in MM and lymphoma cases were identified. PBSC mobilization yielded sufficient CD34+ cell counts both in MM and lymphoma patients; however, the failure rates were relatively high.

Impact of Plerixafor Use at Different Peripheral Blood CD34+ Thresholds on Autologous Stem Cell Collection in Patients with Multiple Myeloma

Patients with multiple myeloma (MM) scheduled for autologous stem cell transplantation must undergo autologous stem cell mobilization; unfortunately, however, many do not obtain an adequate collection yield. Despite the availability of plerixafor, its widespread and uniform use is limited by its cost, and consequently, many institutions have adopted various risk-adapted algorithms. We report our mobilization experience as we have modified our plerixafor algorithm to a more liberal one, with the expectation of greater collection efficiency and mobilization success with higher plerixafor use. A total of 344 mobilization attempts were analyzed over 3 time periods and using 3 different peripheral blood CD34⁺ cell counts to guide plerixafor use: <15/µL (n = 66), <20/µL (n = 130), and <40/µL (n = 148). The primary endpoints were evaluation of changes in mean plerixafor utilization and apheresis days and assessment of the impact on overall mobilization costs. Secondary endpoints were a description of the impact of lenalidomide use on mobilization and evaluation of the rate of mobilization failure. We found that mean plerixafor use increased from 1.32 to 1.65 to 1.74 doses per mobilization (P = .026) and the mean days of apheresis decreased from 2.15 to 2.17 to 1.89 days per mobilization for the <15/µL, <20/µL, and <40/µL cohorts, respectively (P = .011). The combined cost of plerixafor and apheresis procedures at a threshold of 40/µL is close to that at a threshold of 15/µL, while saving 26 apheresis days per 100 patients. In general, there were low rates of mobilization failure across all thresholds. Patients who received more than 6 cycles of lenalidomide demonstrated impaired mobilization and required more apheresis sessions (P < .013) and greater plerixafor use (P < .001) to achieve target stem cell yields. Overall, using plerixafor in patients with MM, with a day 4 pCD34 count of <40/µL is a reasonable and cost-effective strategy to optimize apheresis utilization.

The impact of multiple myeloma induction therapy on hematopoietic stem cell mobilization and collection: 25-year experience

While first-line induction therapy for patients with multiple myeloma has changed over the years, autologous hematopoietic stem cell transplantation still plays a significant role, improving both depth of response and progression-free survival of myeloma patients. Our 25-year experience in mobilizing hematopoietic stem and progenitor cells for 472 transplant-eligible myeloma patients was retrospectively reviewed. Patients were stratified according to the remission induction therapy received, and the outcomes were compared among the cohorts that received vincristine, adriamycin and dexamethasone (VAD) (n = 232), bortezomib and dexamethasone (BD) (n = 86), cyclophosphamide, bortezomib and dexamethasone (CyBorD) (n = 82) and other regimens (n = 67). Cyclophosphamide plus granulocyte colony-stimulating factor was the predominant mobilization regimen given. A greater number of CD34⁺ cells (9.9 × 10E6/kg, p = 0.026) was collected with less hospital admissions in BD patients (13%, p = 0.001), when compared to those receiving VAD (7.5 × 10E6/kg, 29%), CyBorD (7.6 × 10E6/kg, 19%), or other regimens (7.9 × 10E6/kg, 36%). Induction therapy did not influence the overall rate of unscheduled visits or the length of hospitalization because of complications following mobilization. The myeloma response was not significantly deepened following the cyclophosphamide administered for mobilization. This analysis demonstrates the importance of monitoring the impact of initial treatment on downstream procedures such as stem cell mobilization and collection.

Comparison and cost analysis of three protocols for mobilization and apheresis of haematopoietic progenitor cells

INTRODUCTION

Autologous bone marrow transplantation is a component of the malignant hemopathy therapy. The preferred mobilization and collection method is apheresis. The aim of this study is to compare three protocols analyzing the effect of plerixafor, higher dose of G-CSF and large volume leukapheresis (LVL).

MATERIALS AND METHODS

A retrospective cohort study including 119 patients referred for mobilization. Three protocols were compared: (a) G-CSF 10 μg/kg/day subcutaneous (sc) × 4 days mobilizing 1 to 1.5 blood volumes. (b) G-CSF 10 μg/kg/day sc × 4 days + plerixafor 0.24 mg/kg/day sc preventively or as a rescue agent mobilizing 1 to 1.5 blood volumes. (c) G-CSF 20 μg/kg/day sc × 4 days ± plerixafor 0.24 mg/kg/day sc preventively or as a rescue agent mobilizing 3 to 4 blood volumes.

RESULTS

The average number of days of apheresis was reduced to 1.37 with protocol 3. The average cost per patient was reduced by 67% compared with protocol 2 and increased by only 5% compared with protocol 1, reducing the failure rate to 0%.

CONCLUSION

Adding preemptive or rescue plerixafor (protocol 2) to G-CSF 10 μg/kg/day alone (protocol 1) did not improve the days of apheresis nor the number of CD34+ cells collected but had higher cost and failure rate. Using LVL, plerixafor and G-CSF 20 μg/kg/day (protocol 3) decreased the number of sessions to 1.37, reduced the failure rate to 0% and led to a significant increase in the number of CD34+ cells collected without toxicity and with a similar cost to protocol 1.

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.

Autologous hematopoietic progenitor cell mobilization and collection in adult patients presenting with multiple myeloma and lymphoma: A position-statement from the Turkish Society of Apheresis (TSA)

Autologous hematopoietic cell transplantation (AHCT) is a routinely used procedure in the treatment of adult patients presenting with multiple myeloma (MM), Hodgkin lymphoma (HL) and various subtypes of non-Hodgkin lymphoma (NHL) in upfront and relapsed/refractory settings. Successful hematopoietic progenitor cell mobilization (HPCM) and collection are the rate limiting first steps for application of AHCT. In 2015, almost 1700 AHCT procedures have been performed for MM, HL and NHL in Turkey. Although there are recently published consensus guidelines addressing critical issues regarding autologous HPCM, there is a tremendous heterogeneity in terms of mobilization strategies of transplant centers across the world. In order to pave the way to a more standardized HPCM approach in Turkey, Turkish Society of Apheresis (TSA) assembled a working group consisting of experts in the field. Here we report the position statement of TSA regarding autologous HPCM mobilization strategies in adult patients presenting with MM and lymphoma.

Dose capping of plerixafor in patients weighing more than 100 kg at one vial led to successful mobilization outcomes and significant cost savings

BACKGROUND

Plerixafor is frequently used as an adjunct agent to improve mobilization of peripheral blood stem cells in many clinical settings. However, its high cost (>$8000 per single-use 24-mg vial) is a significant concern. The manufacturer-recommended dose is 0.24 mg/kg. Therefore, patients weighing more than 100 kg would require a second vial, thus doubling the drug cost per dose. We implemented a policy of capping the dose of plerixafor at 24 mg, or one vial, for patients weighing more than 100 kg. This retrospective study compares the mobilization of patients more than 100 kg who received capped doses, with historical control patients who received full, uncapped doses.

STUDY DESIGN AND METHODS

Consecutive, eligible patients weighing more than 100 kg who received capped (n = 47) and full doses of plerixafor (n = 40) were identified. Plerixafor was given up-front, as a rescue agent due to suboptimal mobilization, or during remobilization. Baseline characteristics and mobilization data were collected and compared.

RESULTS

Patients in the two groups showed comparable baseline characteristics. They collected similar total numbers of CD34+ cells/kg (median, 4.08 × 10⁶ vs. 3.36 × 10⁶ CD34+ cells/kg; p = 0.86) and achieved comparable collection success rates as defined by collecting more than 2.0 × 10⁶ CD34+ cells/kg (98% vs. 90%, p = 0.21). However, patients who received capped doses required only half of the number of vials of plerixafor (median, 3 vials vs. 6 vials; p < 0.0001).

CONCLUSION

Dose capping plerixafor at 24 mg for patients more than 100 kg is a cost-effective strategy, which achieved comparable mobilization outcomes and reduced the total number of vials of plerixafor used by half.

Current practice of autologous hematopoietic progenitor cell mobilization in adult patients with multiple myeloma and lymphoma: The results of a survey from Turkish hematology research and education group (ThREG)

Autologous hematopoietic cell transplantation (AHCT) is an established treatment option for adult patients presenting with multiple myeloma (MM), Hodgkin lymphoma (HL) and various subtypes of non-Hodgkin lymphoma (NHL) in upfront and/or relapsed/refractory disease settings. Although there are recently published consensus guidelines addressing critical issues regarding autologous hematopoietic progenitor cell mobilization (HPCM), mobilization strategies of transplant centers show high variability in terms of routine practice. In order to understand the current institutional policies regarding HPCM in Turkey and to obtain the required basic data for preparation of a national positional statement on this issue, Turkish Hematology Research and Education Group (ThREG) conducted a web-based HPCM survey. The survey was designed to include multiple-choice questions regarding institutional practice of HPCM in adults presenting MM, HL, and NHL. The representatives of 27 adult HCT centers participated to the study. Here we report the results of this survey shedding light on the real-world experience in Turkey in terms of autologous HPCM mobilization strategies in patients presenting with MM and lymphoma.

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

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

A single center's experience using four different front line mobilization strategies in lymphoma patients planned to undergo autologous hematopoietic cell transplantation

In an otherwise eligible patient with relapsed lymphoma, inadequate mobilization of peripheral blood stem cells is a limiting factor to proceeding with an autologous hematopoietic cell transplantation (auto-HCT). Multiple strategies have been used to mobilize an adequate number of hematopoietic stem cells (HSCs) with no obvious front-line strategy. We report a single institutional experience mobilizing HSCs using four different approaches in lymphoma patients. We prospectively collected mobilization outcomes on patients planning to undergo auto-HCT at Ohio State University. We report results of first mobilization attempt for all relapsed or refractory lymphoma patients between 2008–2014. We identified 255 lymphoma patients who underwent mobilization for planned auto-HCT. The 255 lymphoma patients underwent the following front line mobilization strategies: 95 (37%) GCSF alone, 38 (15%) chemomobilization (GCSF+chemotherapy), 97 (38%) preemptive day 4 plerixafor, and 25 (10%) rescue day 5 plerixafor. As expected, there were significant differences between cohorts including age, comorbid indices, histology, and amount of prior chemotherapy. After controlling for differences between groups, the odds of collecting 2×10⁶/kg HSCs on the first day of collection and 5×10⁶/kg HSCs in total was highest in the cohort undergoing chemomobilization. In conclusion, our experience highlights the effectiveness of chemomobilization.

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.

Blood graft cellular composition and posttransplant outcomes in myeloma patients mobilized with or without low-dose cyclophosphamide: a randomized comparison

BACKGROUND

Autologous stem cell transplantation is a standard treatment in multiple myeloma (MM). Blood grafts are usually collected after mobilization with granulocyte-colony-stimulating factor (G-CSF) alone or in a combination with cyclophosphamide (CY). There is limited knowledge of the possible effects of different mobilization regimens on blood graft characteristics and posttransplant outcomes.

STUDY DESIGN AND METHODS

Thirty-eight patients with MM were included in this study. The patients were randomly assigned at registration to mobilization with either low-dose CY plus G-CSF (Arm A) or G-CSF alone (Arm B) and received three cycles of lenalidomide, bortetzomib, and dexamethasone induction. Flow cytometry analysis of lymphocyte subsets in the blood grafts after cryopreservation was performed. Hematologic and immune recovery were evaluated up to 12 months posttransplant.

RESULTS

The blood grafts in Arm A contained significantly more CD34+ cells but in Arm B there was a greater proportion of CD34+CD38- cells and higher numbers of T and B lymphocytes as well as natural killer (NK) cells. The engraftment was comparable but lymphocyte count at 15 days posttransplant was higher in Arm B (0.8 × 10(9) /L vs. 0.5 × 10(9) /L, p = 0.033). At 3 and 6 months posttransplant the total number of NK cells was also higher in G-CSF-mobilized patients. There was no difference in progression-free survival between the study arms.

CONCLUSION

CY plus G-GSF yields more CD34+ cells but seems to diminish lymphocyte and NK cell counts in the grafts and hampers immune recovery after transplantation. Thus G-CSF alone might be a preferred mobilization method due to more rapid immune recovery posttransplant.

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

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