Plerixafor and granulocyte colony-stimulating factor for first-line steady-state autologous peripheral blood stem cell mobilization in lymphoma and multiple myeloma: results of the prospective PREDICT trial

Stem Cells Collection and Mobilization in Adult Autologous/Allogeneic Transplantation: Critical Points and Future Challenges

Achieving successful hematopoietic stem cell transplantation (HSCT) relies on two fundamental pillars: effective mobilization and efficient collection through apheresis to attain the optimal graft dose. These cornerstones pave the way for enhanced patient outcomes. The primary challenges encountered by the clinical unit and collection facility within a transplant program encompass augmenting mobilization efficiency to optimize the harvest of target cell populations, implementing robust monitoring and predictive strategies for mobilization, streamlining the apheresis procedure to minimize collection duration while ensuring adequate yield, prioritizing patient comfort by reducing the overall collection time, guaranteeing the quality and purity of stem cell products to optimize graft function and transplant success, and facilitating seamless coordination between diverse entities involved in the HSCT process. In this review, we aim to address key questions and provide insights into the critical aspects of mobilizing and collecting hematopoietic stem cells for transplantation purposes.

Long-Term Outcomes of Autologous Hematopoietic Stem Cell Transplant (HSCT) for Multiple Myeloma: While New Horizons Emerge, It Is Still Only a Silver Lining for Resource-Constrained Settings

Background Significant hurdles impede the optimal implementation of hematopoietic stem cell transplantation (HSCT) in low-middle income countries (LMICs). Herein, we highlight the challenges faced in LMICs while performing HSCT and report the long-term outcomes of patients with newly diagnosed multiple myeloma (MM) who underwent autologous HSCT (AHSCT) at our center. Besides, we provide a comprehensive review of studies reporting long-term outcomes of AHSCT in MM from the Indian subcontinent. Methodology This study was conducted at the State Cancer Institute, Sher-i-Kashmir Institute of Medical Sciences, Srinagar, India. Case records of all patients with MM who received AHSCT from December 2010 to July 2018 were reviewed retrospectively. A non-systematic literature search was performed using PubMed and Google Scholar databases. Data regarding clinicopathological parameters and long-term follow-up were extracted from relevant studies and for patients included in our study. Results At our center, 47 patients (median age 52.0 years) with MM underwent AHSCT. Majority of patients had stage III disease (ISS) and median time to transplant was 11.5 months. The five-year progression free survival (PFS) and overall survival (OS) were 59.1% and 81.2%, respectively. Studies from the Indian subcontinent have observed a five-year OS of ~50% to ~85%. However, a greater variability in the five-year PFS has been reported, ranging from ~20% to ~75%. The median time to transplant has ranged from seven to 17 months (indicating time delays) with median CD34 cell counts of 2.7-6.3×106 cells/kg (lower than developed countries). Conclusions Despite significant resource limitations in LMICs, AHSCT is increasingly been performed in MM with encouraging long-term outcomes.

A Comparison of Four Leukapheresis Methods to Harvest an Optimal Dose of CD34+ Cells: A Single Center Experience

BACKGROUND

Chemokine receptor CXCR4 antagonist plerixafor (Px) as well as high volume (HV) leukapheresis have been shown to reduce hematopoietic stem progenitor cell (HSPC) mobilization failure rates. However, no direct comparisons of such methods currently exists.

METHODS AND MATERIALS

We compared the HSPC collection yield based on basal peripheral blood CD34+ cell numbers in patients diagnosed with multiple myeloma or non-Hodgkin's lymphoma undergoing autologous stem cell transplantation in a retrospective chart review. The leukapheresis methods used included HV vs. regular volume (RV) with or without Px. There were 116 patients in the study group while the historical control group had 34 patients.

RESULTS AND CONCLUSIONS

Control group underwent RV leukapheresis without Px. Addition of Px or HV in the study group failed to display significant improvement in CD34+ cell collection yield; however, when basal CD34+ cell numbers were taken into account, both Px+RV and HV without Px increased CD34+ cell collection yield. The collection failure rates of HV without Px group were comparable to Px+RV when the basal CD34+ cell numbers were over 20/μL. Of interest, multivariate linear regression analysis did not detect any significant difference between HV vs Px+RV or other leukapheresis methods in CD34 yields or collection failure rates from a single collection after controlling for other factors (sex, age or underlying disease). In multivariate analysis, pre apheresis CD34+ cell number was significantly and positively associated with the CD34+ cell yields from a single apheresis. In our studies, the majority of patients can be rescued without Px by HV alone as a potential cost saving approach. In summary, trend in our studies reflects that both Px and HV are capable of reducing the mobilization failure rates except the poorest mobilizers which will need to be validated in larger studies. This article is protected by copyright. All rights reserved.

Induction therapy prior to autologous stem cell transplantation (ASCT) in newly diagnosed multiple myeloma: an update

The current standard of care model for newly diagnosed fit multiple myeloma (NDMM) patients is the sequential treatment of induction, high dose melphalan, autologous stem cell transplantation (ASCT), and maintenance. Adequate induction is required to achieve good disease control and induce deep response rates while minimizing toxicity as a bridge to transplant. Doublet induction regimens have greatly fallen out of favor, with current international guidelines favoring triplet or quadruplet induction regimens built around the backbone of the proteasome inhibitor bortezomib and dexamethasone (Vd). In fact, the updated 2021 European Haematology Association (EHA) and European Society for Medical Oncology (ESMO) clinical practice guidelines recommend the use of either lenalidomide-Vd (VRd), or daratumumab-thalidomide-Vd (Dara-VTd) as first-line options for transplant-eligible NDMM patients, and when not available, thalidomide-Vd (VTd) or cyclophosphamide-Vd (VCd) as acceptable alternatives. Quadruplet regimens featuring anti-CD38 monoclonal antibodies are extremely promising and remain heavily investigated, as is the incorporation of more recent proteasome inhibitors such as carfilzomib. This review will focus on induction therapies prior to ASCT examining the latest data and guidelines on triplet and quadruplet regimens.

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.

Collection and Processing of Mobilized Mouse Peripheral Blood at Lowered Oxygen Tension Yields Enhanced Numbers of Hematopoietic Stem Cells

Mobilized peripheral blood (mPB) hematopoietic stem (HSCs) and progenitor (HPCs) cells are primary sources for hematopoietic cell transplantation (HCT). Successful HCT requires threshold numbers of high-quality HSCs to reconstitute hematopoiesis long-term. Nevertheless, considerable percentages of patients and healthy donors fail to achieve required thresholds of HSCs with current mobilization regimens. In this present study we demonstrate that similar to mouse bone marrow (BM) and human cord blood, collection and processing of mouse Granulocyte Colony Stimulating Factor (G-CSF)-, AMD3100/Plerixafor- or G-CSF plus AMD3100/Plerixafor-mobilized HSCs in 3% O₂ results in enhanced numbers of rigorously-defined phenotypic and for G-CSF - and G-CSF plus AMD3100/Plerixafor - mPB enhanced functionally-engrafting HSCs. These results may be of potential clinical utility. Graphical Abstract.

Successful autologous peripheral blood stem cell collection using large volume leukapheresis in patients with very low or undetectable peripheral blood CD34+ progenitor cells

Autologous stem cell transplantation provides some patients with hematolymphoid and solid organ malignancies an opportunity for cure. Management of peripheral hematopoietic stem cell (HSC) collections differs among institutions, especially if a very low pre-procedure peripheral blood CD34+ cell count (PBCD34) is demonstrated. This study retrospectively analyzed results of large-volume peripheral HSC collections in 91 patients over approximately two years. Fifteen patients with PBCD34 < 10 × 10e6/l (eleven with undetectable PBCD34) were compared to 76 patients with higher counts on the first collection day (adequate mobilizers). The poor mobilizer group had significantly lower pre-collection WBC and platelet counts as well as collection yields. However, most patients with PBCD34 < 10 × 10e6/l (80 %) collected the minimum target for HSC transplant (2.0 × 10e6 CD34+ cells/kg) in <5 consecutive days of collection, and those who did collect the minimum successfully underwent autologous transplantation, with hematopoietic engraftment and long-term survival comparable to the adequate mobilizers. Successful HSC collection may often be achieved regardless of d 1 PBCD34 counts.

Engraftment after autologous hematopoietic stem cell transplantation in patients mobilized with Plerixafor: A retrospective, multicenter study of a large series of patients

Plerixafor (PLX) appears to effectively enhance hematopoietic stem-cell mobilization prior to autologous hematopoietic stem cell transplantation (auto-HCT). However, the quality of engraftment following auto-HCT has been little explored. Here, engraftment following auto-HCT was assessed in patients mobilized with PLX through a retrospective, multicenter study of 285 consecutive patients. Information on early and 100-day post-transplant engraftment was gathered from the 245 patients that underwent auto-HCT. The median number of PLX days to reach the stem cell collection goal (≥2 × 10⁶ CD34⁺ cells/kg) was 1 (range 1-4) and the median PLX administration time before apheresis was 11 h (range 1-18). The median number of apheresis sessions to achieve the collection goal was 2 (range 1-5) and the mean number of CD34⁺ cells collected was 2.95 × 10⁶/kg (range 0-30.5). PLX administration was safe, with only 2 mild and transient gastrointestinal adverse events reported. The median time to achieve an absolute neutrophil count (ANC) >500/μL was 11 days (range 3-31) and the median time to platelet recovery >20 × 10³/μL was 13 days (range 5-69). At 100 days after auto-HCT, the platelet count was 137 × 10⁹/L (range 7-340), the ANC was 2.3 × 10⁹/L (range 0.1-13.0), and the hemoglobin concentration was 123 g/L (range 79-165). PLX use allowed auto-HCT to be performed in a high percentage of poorly mobilized patients, resulting in optimal medium-term engraftment in the majority of patients in whom mobilization failed, in this case mainly due to suboptimal peripheral blood CD34⁺ cell concentration on day +4 or low CD34⁺ cell yield on apheresis.

[Analysis of the efficacy and safety of plerixafor combined with G-CSF in plasma cell disease mobilization]

目的

分析普乐沙福联合G-CSF在浆细胞疾病自体造血干细胞中动员的效果及安全性。

方法

回顾性分析2018年1月至2019年12月在北京大学人民医院使用普乐沙福联合G-CSF进行自体造血干细胞动员的浆细胞疾病患者的基线临床资料、采集成功率及不良反应。

结果

共纳入49例浆细胞疾病患者，多发性骨髓瘤（MM）39例（79.6%），淀粉样变性8例（16.3%），肾脏意义的单克隆免疫球蛋白沉积病（MGRS）2例（4.1%），肾功能不全16例（32.7%）。其他动员方案既往采集失败患者7例（14.3%）。使用普乐沙福动员后，中位采集次数1（1～3）次，中位采集天数2（1～3）d，一次采集成功47例（95.9%），两次采集累积成功率为100%。在16例肾功能不全的患者中，5例（31.3%）患者第1天采集成功，8例（50%）需要第2天采集，3例（18.8%）需要第3天采集。主要不良反应依次为乏力、失眠、腹痛、腹泻、头晕、关节痛。共37例患者行auto-HSCT，白细胞中位植活时间11（8～13）d，血小板中位植活时间11（9～26）d。

结论

普乐沙福联合G-CSF用于浆细胞疾病患者自体造血干细胞动员成功率高，不良反应少，即使在肾功能不全的患者中也具有较高的动员成功率。

Plerixafor added to G-CSF allows mobilization of a sufficient number of hematopoietic progenitors without impacting the efficacy of TCR-alpha/beta depletion in pediatric haploidentical and genoidentical donors failing to mobilize with G-CSF alone

BACKGROUND

Collection of a large number of early hematopoietic progenitors is essential for allogeneic apheresis products intended for TCR-alpha/beta depletion.

MATERIALS AND METHODS

We added plerixafor 0.24 mg/kg body weight (bw) on day 4 of high-dose filgrastim mobilization 10 hours prior to apheresis in 16 (30.5%) pediatric allogeneic donors who failed to recover a sufficient number of CD34+ cells.

RESULTS

On day 4 of G-CSF, the median CD34+ cell count in peripheral blood was 6 per μL (range 4-9 per μL) in 6 poor mobilizers and 16 per μL (range 12-19 per μL) in insufficient mobilizers. In all donors, the threshold of 50 CD34+ cells/μL was achieved, and the median increase was 14.8-fold in poor mobilizers and 6.5-fold in insufficient mobilizers, whereas it was 3.45-fold increase in those mobilized with G-CSF alone.

DISCUSSION

In all donors, a predefined number of >10 × 10⁶ CD34+ cells/kg of recipient bw before depletion was reached in the apheresis product. The use of plerixafor did not affect the purity of further TCR-alpha/beta depletion. Side effects were mild to moderate and consisted of nausea and vomiting.

CONCLUSION

Thus, the safety and high efficacy of plerixafor was proven in healthy pediatric allogeneic hematopoietic cell donors.

YF-H-2015005, a CXCR4 Antagonist, for the Mobilization of Hematopoietic Stem Cells in Non-Hodgkin Lymphoma Patients: A Randomized, Controlled, Phase 3 Clinical Trial

Background: YF-H-2015005, a novel CXCR4 antagonist, has been proven to increase the quantities of circulating hematopoietic stem cells (HSCs), which results in an adequate collection of HSCs in non-Hodgkin lymphoma (NHL) patients.

Methods: This was a multicenter, double-blind, randomized (1:1), placebo-controlled phase III clinical trial. All patients received granulocyte colony-stimulating factor (G-CSF) for up to 8 consecutive days. YF-H-2015005 or placebo was administrated on the evening of day 4 and continued daily for up to 4 days. Apheresis was conducted 9–10 h after each dose of YF-H-2015005 or placebo. The primary endpoint was the proportion of NHL patients procuring ≥5 × 10⁶/kg CD34⁺ HSCs within ≤4 apheresis sessions.

Results: In total, 101 patients with NHL were enrolled. The proportions of patients achieving primary endpoint were 57 and 12% in YF-H-2015005 and placebo groups, respectively (P < 0.001). Moreover, a higher proportion of YF-H-2015005-treated patients reached a minimum target collection of ≥2 × 10⁶/kg CD34⁺ HSCs in ≤4 apheresis days compared to placebo-treated patients (86 vs. 38%, P < 0.001). Furthermore, the median time to collect ≥2 or 5 × 10⁶/kg CD34+ HSCs were 1 and 3 days in YF-H-2015005-treated patients, but 4 days and not reached in placebo-treated patients, respectively. No severe treatment emergent adverse events were observed in both YF-H-2015005 treatment and placebo groups.

Conclusions: YF-H-2015005 plus G-CSF regimen was a tolerable combination with high efficacy, which might be used to rapidly mobilize and collect HSCs in NHL patients.

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

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

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

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

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

Combined G-CSF and Plerixafor enhance hematopoietic recovery of CD34+ cells from poor mobilizer patients in NSG mice

Transplantable CD34⁺ hematopoietic stem/progenitor cells (HSPCs) are currently isolated mainly from peripheral blood after mobilization with granulocyte colony-stimulating factor (G-CSF). These mobilized CD34⁺ cells have the potential to generate all blood cell types. For autologous transplantation, the minimal number of mobilized CD34⁺ cells is 2 × 10⁶ CD34⁺ cells/kg body weight. However, up to 30% of patients fail to mobilize enough peripheral CD34⁺ cells after G-CSF treatment. To overcome this limitation, a combination of G-CSF and Plerixafor, a CXCR4 chemokine receptor inhibitor, is proposed to enhance CD34⁺ cell mobilization in poor mobilizer patients. However, only limited data are available on quantification of the functional quality of such patients' mobilized hematopoietic stem cells. Here, for six poor mobilizer patients, a head-to-head comparison of their CD34⁺ cells mobilized without versus with Plerixafor was performed to assess their properties with respect to the reconstitution of human hematopoiesis in vivo in immune-deficient mice. Our results indicate that mobilized CD34⁺ cells recovered after the G-CSF + Plerixafor mobilization protocol have an enhanced intrinsic hematopoietic reconstitution potential compared with CD34⁺ cells mobilized with G-CSF alone.

Clinical significance of chemokine receptor antagonists

Introduction: Chemokine receptors are important therapeutic targets for the treatment of many human diseases. This study will provide an overview of approved chemokine receptor antagonists and promising candidates in advanced clinical trials.Areas covered: We will describe clinical aspects of chemokine receptor antagonists regarding their clinical efficacy, mechanisms of action, and re-purposed applications.Expert opinion: Three chemokine antagonists have been approved: (i) plerixafor is a small-molecule CXCR4 antagonist that mobilizes hematopoietic stem cells; (ii) maraviroc is a small-molecule CCR5 antagonist for anti-HIV treatment; and (iii) mogamulizumab is a monoclonal-antibody CCR4 antagonist for the treatment of mycosis fungoides or Sézary syndrome. Moreover, phase 3 trials are ongoing to evaluate many potent candidates, including CCR5 antagonists (e.g. leronlimab), dual CCR2/CCR5 antagonists (e.g. cenicriviroc), and CXCR4 antagonists (e.g. balixafortide, mavorixafor, motixafortide). The success of chemokine receptor antagonists depends on the selective blockage of disease-relevant chemokine receptors which are indispensable for disease progression. Although clinical translation has been slow, antagonists targeting chemokine receptors with multifaced functions offer the potential to treat a broad spectrum of human diseases.

Inferior prognosis in poor mobilizing myeloma patients

INTRODUCTION

Induction treatment followed by autologous stem cell transplantation (ASCT) has been accepted as the standard treatment for multiple myeloma (MM) patients. Granulocyte colony stimulating agent (G-CSF), chemotherapy or agents likes plerixafor are being used for the mobilization of stem cells from bone marrow. In this study, we evaluated the impact of the mobilization methods on the outcome of MM patients after ASCT.

METHOD

The data of 205 MM patients who underwent ASCT at our center between December 2009 and January 2019 were retrospectively analyzed. Patients were divided into 2 groups as good mobilizers (patients who were mobilized with G-CSF alone) and poor mobilizers (patients who were failed to mobilize with G-CSF alone and mobilized with G-CSF + cylophosphomide or G-CSF + plerixafor).

RESULTS

The median progression free survival (PFS) was 18.27 ± 3.22 months in good mobilizers and 14.22 ± 3.7 months in poor mobilizers. In G-CSF + cyclophosphamide method median PFS was 15.4 ± 4.9 months wheras it was only 4 months in G-CSF + plerixafor method. We did not find a statistically significant difference between good and poor mobilizers regarding median PFS (p: 0.342). The median overall survival (OS) was found 34.48 ± 4.2 months in good mobilizers and 15.13 ± 5.78 months in poor mobilizers. In G-CSF + cyclophosphamide method median OS was 17 ± 14.01 months wheras it was 10.66 ± 7.68 months in G-CSF + plerixafor method. We found a statistically significant difference between good and poor mobilizers regarding median OS (p: 0.007*).

CONCLUSION

Our study shows that difficulty in stem cell mobilization is correlated with worse outcome.

Preemptive and Upfront Plerixafor: Safe and Effective Strategy for Patients Undergoing Autologous Stem Cell transplant and at High Risk for Mobilization Failure

Introduction: Approximately 10%–30% of patients are unable to collect the minimum number of stem cells to support high-dose chemotherapy and autologous stem cell transplant (hematopoietic stem cell transplantation). Plerixafor alone or in combination with granulocyte colony-stimulating factor (G-CSF) has been shown to significantly increase the CD34 cell collection, especially in patients who failed their initial harvest strategy. This is a retrospective study of 17 preselected patients (relapsed lymphoma and myeloma), who were considered to have high risk of mobilization failure and who had undergone upfront and preemptive plerixafor mobilization. Patients and Methods: The mobilization protocol consisted of G-CSF (10–15 μg/kg) subcutaneously daily for 4 days before the initiation of plerixafor on evening of day 4. The patients then underwent apheresis on day 5. Results: Among 17 patients who underwent apheresis, 16 (93%) yielded the minimum required cell collection of ≥2 × 106 CD34+ cells/kg in a single apheresis session (2 days). Out of these 16 patients, 8 (53%) patients achieved the minimum target dose in a single day. Eight (50%) of all patients achieved the optimum target cell collection in a single apheresis session. Out of these eight patients, five (62%) patients collected optimum yield in a single day. Conclusion: Plerixafor is safe and effective if used upfront and preemptively for patients in whom mobilization of stem cells is considered to be a problem.

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.

Efficacy and safety of plerixafor for hematopoietic stem cell mobilization for autologous transplantation in patients with non-Hodgkin lymphoma and multiple myeloma: A systematic review and meta-analysis

Plerixafor in combination granulocyte-colony stimulating factor (G-CSF) has been used for the mobilization of hematopoietic stem cells (HSCs) to the peripheral blood for collection and subsequent autologous transplantation in patients with non-Hodgkin lymphoma (NHL) and multiple myeloma (MM). The aim of this study was to systematically search the published literature and analyze evidence on the efficacy of additional plerixafor for successful HSC mobilization in patients with NHL and MM, and to evaluate the safety of the drug. The PubMed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL) and Google scholar databases were searched electronically for studies published in the English language up to March, 2019. Five studies (3 on NHL and 2 on MM) were included in this review article. The meta-analysis of data of 364 patients in the treatment group and 368 patients in the control group, indicated that the mobilization of ≥5/6×10⁶ CD34⁺ cells/kg in 4 or less apheresis days was superior with plerixafor + G-CSF than with G-CSF alone (RR=2.59, 95% CI: 1.40 to 4.81; P<0.0001). Similarly, a greater proportion of patients in the treatment group exhibited the mobilization of ≥2×10⁶ CD34⁺ cells/kg in 4 or less apheresis days (RR=1.46, 95% CI: 1.01 to 2.12; P=0.04). The addition of plerixafor significantly increased the total collection of CD34⁺ cells (random: MD=4.21; 95% CI: 2.85 to 5.57; P<0.00001). Meta-analysis indicated no significant increase in adverse events with the addition of plerixafor for HSC mobilization (RR=1.03, 95% CI: 0.99 to 1.06; P=0.16). On the whole, the findings of this study indicate that the addition of plerixafor to G-CSF leads to an increased HSC collection in a shorter period of time with no concomitant increase in adverse events. Further randomized controlled trials with a larger sample size evaluating short term efficacy, as well as long term survival would help to further strengthen the evidence on this subject.

Successful hematopoietic stem-cell mobilization with plerixafor plus granulocyte-colony stimulating factor in multiple myeloma patients treated with pomalidomide

Autologous stem-cell transplantation is an effective procedure for the treatment of multiple myeloma, and involves the collection of hematopoietic stem cells (HSCs). However, in some patients, HSCs in the bone marrow fail to mobilize. Pomalidomide upregulates CXCR4 in hematopoietic stem cells, in a manner similar to that of lenalidomide, and is, thus, likely to have a negative impact on hematopoietic stem-cell mobilization in multiple myeloma patients. Here, we report the two cases in which hematopoietic stem cells were mobilized using plerixafor plus granulocyte-colony stimulating factor after exposure to lenalidomide and pomalidomide. Use of plerixafor with a sufficient washout period may lead to successful mobilization following pomalidomide use, although further study of this potential use is needed.

Current status of autologous stem cell transplantation for multiple myeloma

More than 30 years after its introduction, autologous stem cell transplantation (ASCT) remains the standard of care for young patients with newly diagnosed multiple myeloma. Not only did the arrival of novel agents such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PI) and monoclonal antibodies not replace ASCT, instead they solidified its central role as standard of care. Novel agent use is now inarguably essential in induction, maintenance, and possibly consolidation. In light of these new advancements, new challenges arise in deciding on optimal practice. Who is most suited to undergo ASCT? Is there an age threshold that should not be surpassed? Should transplantation be embarked on early or is it reasonable to delay it? What are the optimal induction, consolidation, and maintenance therapies? What is the role of tandem transplantation in the era of novel agents and where do patient-specific cytogenetics come into the equation when deciding on treatment? These are some of the questions addressed in this review which we will attempt to answer with the latest currently available data.

Blood graft composition and post-transplant recovery in myeloma patients mobilized with plerixafor: a prospective multicenter study

The composition of autologous blood grafts after cryopreservation, post-transplant hematological recovery up to 1 year and immune recovery up to 6 months as well as outcome was analyzed in 87 patients with multiple myeloma (MM). The patients receiving added plerixafor due to poor mobilization (11%) were compared to those mobilized with G-CSF or cyclophosphamide (CY) plus G-CSF. The use of plerixafor was found to significantly affect the graft composition as there was a significantly higher proportion of the more primitive CD34⁺ cells, higher number of T and B lymphocytes as well as NK cells in the grafts of patients who received also plerixafor. The hematological recovery after auto-SCT was comparable between the groups. The recovery of CD3⁺CD4⁺ T cells was faster in plerixafor mobilized patients at 1 and 3 months post-transplant. There were no significant differences in progression-free (PFS) or overall survival (OS) according to the plerixafor use.

A Pilot, Exploratory, Randomized, Phase II Safety Study Evaluating Tumor Cell Mobilization and Apheresis Product Contamination in Patients Treated with Granulocyte Colony-Stimulating Factor Alone or Plus Plerixafor

Because of the potential risk of tumor cell mobilization with granulocyte colony-stimulating factor (G-CSF), it is crucial to evaluate any potential effect of plerixafor treatment in the presence of G-CSF on multiple myeloma (MM) cell mobilization. This was an open-label, multicenter, randomized, exploratory, safety study (NCT01753453) that investigated the extent of MM cell mobilization after treatment with G-CSF + plerixafor in patients who were deemed poor mobilizers of hematopoietic stem cells. The primary efficacy outcome was the number of MM cells in peripheral blood and apheresis product after G-CSF + plerixafor treatment versus G-CSF alone. Key secondary efficacy outcomes included overall survival and disease status up to 2 years after the first G-CSF dose. Twenty patients were randomized and received at least 1 dose of study treatment. There were no patients with MM cells in peripheral blood up to day 8 G-CSF administration in either treatment group. Up to day 8 no patient in the G-CSF + plerixafor arm and only 1 patient in the G-CSF arm mobilized at least 4.5 × 10⁵ MM cells in the apheresis product. Nine of 10 patients from each treatment arm proceeded to transplantation. MM cells were detected in 5 patients from each treatment arm before and after transplantation. Adverse events observed in the G-CSF + plerixafor arm were consistent with the known safety profile of plerixafor. No MM cells were detected in peripheral blood of either treatment group up to day 8 of mobilization. Only 1 patient in the G-CSF alone group mobilized at least 4.5 × 10⁵ MM tumor cells in apheresis product up to day 8. However, 50% of patients in both treatment arms had detectable amounts of MM cells in their peripheral blood pre- and post-transplantation. There were no new safety concerns with plerixafor.

Preemptive plerixafor injection added to pegfilgrastim after chemotherapy in non-Hodgkin lymphoma patients mobilizing poorly

Filgrastim is usually combined with chemotherapy to mobilize hematopoietic progenitor cells in non-Hodgkin lymphoma (NHL) patients. Limited information is available on the efficacy of a preemptive plerixafor (PLER) injection in poor mobilizers after chemotherapy and pegfilgrastim. In this prospective study, 72 patients with NHL received chemotherapy plus pegfilgrastim, and 25 hard-to-mobilize patients received also PLER. The usefulness and efficacy of our previously developed algorithm for PLER use in pegfilgrastim-containing mobilization regimen were evaluated as well as the graft cellular composition, hematological recovery, and outcome after autologous stem cell transplantation (auto-SCT) according to the PLER use. A median 3.4-fold increase in blood CD34⁺ cell counts was achieved after the first PLER dose. The minimum collection target was achieved in the first mobilization attempt in 66/72 patients (92%) and 68 patients (94%) proceeded to auto-SCT. An algorithm for PLER use was fulfilled in 76% of the poor mobilizers. Absolute numbers of T-lymphocytes and NK cells were significantly higher in the PLER group, whereas the number of CD34⁺ cells collected was significantly lower. Early neutrophil engraftment was slower in the PLER group, otherwise hematological recovery was comparable within 12 months from auto-SCT. No difference was observed in survival according to the PLER use. Chemotherapy plus pegfilgrastim combined with preemptive PLER injection is an effective and convenient approach to minimize collection failures in NHL patients intended for auto-SCT. A significant effect of PLER on the graft cellular composition was observed, but no difference in outcome after auto-SCT was detected.

Myeloid-derived cells in prostate cancer progression: phenotype and prospective therapies

Prostate cancer is the second most common cause of cancer mortality in men in the United States. As is the case for other tumor types, accumulating evidence suggests an important role for myeloid-derived cells in the promotion and progression of prostate cancer. Here, we briefly describe myeloid-derived cells that interact with tumor cells and what is known about their immune suppressive function. We next discuss new evidence for tumor cell-mediated myeloid infiltration via the PI3K/PTEN/AKT signaling pathway and an alternative mechanism for immune evasion that may be regulated by an endoplasmic reticulum stress response. Finally, we discuss several interventions that target myeloid-derived cells to treat prostate cancer.

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.

Molecular Pathways: Deciphering Mechanisms of Resistance to Macrophage-Targeted Therapies

Tumor-associated macrophages (TAMs) are a major cellular component of numerous tumor types. TAM-targeted therapies include depletion strategies, inhibiting their effector functions or reprogramming toward an antitumorigenic phenotype, with varying degrees of efficacy. Here, we review preclinical and clinical strategies to target macrophages in cancer and discuss potential explanations for why some strategies are effective while other approaches have shown limited success. Clin Cancer Res; 23(4); 876-84. ©2016 AACR.

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

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

A nationwide survey of the use of plerixafor in patients with lymphoid malignancies who mobilize poorly demonstrates the predominant use of the "on-demand" scheme of administration at French autologous hematopoietic stem cell transplant programs

BACKGROUND

High-dose chemotherapy supported with autologous stem cell transplantation is a standard therapeutic option for a subset of patients with lymphoid malignancies. Cell procurement is nowadays done almost exclusively through cytapheresis, after mobilization of hematopoietic stem and progenitor cells (HSPCs) from the marrow to peripheral blood (PB). The egress of HSPCs out of hematopoietic niches occurs in various physiologic or nonhomeostatic situations; pharmacologic approaches include the administration of acutely myelosuppressive agents or hematopoietic growth factors such as recombinant human granulocyte-colony-stimulating factor (rHuG-CSF). The introduction of plerixafor, a first-of-its-class molecule that reversibly inhibits the interaction between the chemokine CXCL-12 (also known as SDF-1) and its receptor CXCR-4, has offered new opportunities for the so-called "poor mobilizers" who achieve insufficient mobilization and/or collection with conventional approaches.

STUDY DESIGN AND METHODS

Because of the lack of consensus on a definition for poor mobilizers and the relatively high cost of plerixafor, French competent authorities have mandated a postmarketing survey on its use in routine practice.

RESULTS AND CONCLUSION

We report here the results of this nationwide survey that confirms the clinical efficacy of plerixafor, even in the subset of patients who barely increased PB CD34+ cell count in response to rHuG-CSF-containing mobilization regimen. Furthermore, analysis of this registry showed that despite heterogeneity in medical practices, the early-"on-demand" or "preemptive"-introduction of plerixafor was widely used and did not result in an excess of prescriptions, beyond its expected use at the time when marketing authorization was granted.

Plerixafor prescription modalities in autologous haematopoietic stem cell mobilization in Belgium

OBJECTIVES

The efficacy and safety of plerixafor, an antagonist of the CXCR4 receptor, in combination with G-CSF has been demonstrated in patients suffering from Iymphoma and multiple myeloma (MM) eligible for autologous haematopoietic stem cell collection. However, different reimbursement criteria have been applied in different countries to select patients eligible for treatment with plerixafor. The objective of this observational study was to describe the plerixafor prescription modalities in daily practice in Belgium.

METHODS

This open-label, prospective, observational study was conducted in 11 Belgian centres in 114 patients with lymphoma (Hodgkin's and non-Hodgkin's lymphoma) or MM who were treated with plerixafor according to the SmPC between April 2011 and October 2012. Patients included in another clinical trial with plerixafor were excluded from the study.

RESULTS

The use of plerixafor in patients with MM or lymphoma was effective, with a success rate (defined as a total yield >2×10(6) CD34+ cells/kg) of 77%, and well tolerated (one SAE reported). Optimal collection (defined as a total yield >4×10(6) CD34+ cells/kg) was obtained for 43% of the study population (31% in lymphoma patients, compared to 61% in patients with MM). The use of plerixafor was in line with the SmPC and the Belgian reimbursement criteria for all patients.

CONCLUSION

This study is showing that the use of plerixafor according to Belgian reimbursement criteria results in similar efficacy and safety as in other centres and countries worldwide.

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

This study (PHANTASTIC) compares first-line plerixafor with granulocyte colony-stimulating factor (G-CSF) in 98 myeloma and lymphoma patients with 151 historic controls mobilised by conventional chemotherapy+G-CSF. Eleven patients developed mild transient symptoms possibly related to plerixafor. No serious adverse events were seen. Seventy (71%) plerixafor-mobilised patients achieved both ⩾4 × 10⁶ CD34⁺ cells/kg in ⩽2 aphereses and no neutropenia (<1.0 × 10⁹/l). This is significantly >48 (32%) of 151 historical chemotherapy+G-CSF-mobilised control patients achieving this end point (P<0.001). Ninety-six (98%) plerixafor-mobilised patients achieved ⩾2 × 10⁶ CD34⁺ cells/kg within one harvest round compared with 114 (75%) of controls (P=0.001). Engraftment times and 12-month outcome were comparable in both groups. Prior treatment was summarised by two scoring systems. Controls mobilising either >2.0 or >4.0 × 10⁶ CD34⁺ cells/kg have significantly lower scores than mobilisation failures (P=0.002), but this relationship was not seen for plerixafor-mobilised patients. Plerixafor is a more effective and less toxic mobilising agent than conventional chemotherapy (especially in heavily pretreated patients), with comparable subsequent outcome, and merits consideration as the first-line standard of care for stem cell mobilisation.

Plerixafor plus pegfilgrastim is a safe, effective mobilization regimen for poor or adequate mobilizers of hematopoietic stem and progenitor cells: a phase I clinical trial

The safety, kinetics and efficacy of plerixafor+pegfilgrastim for hematopoietic stem and progenitor cell (HSPC) mobilization are poorly understood. We treated 12 study patients (SP; lymphoma n=10 or myeloma n=2) with pegfilgrastim (6 mg SC stat D1) and plerixafor (0.24 mg/kg SC nocte from D3). Six SP were 'predicted poor-mobilizers' and six were 'predicted adequate-mobilizers'. Peripheral blood (PB) CD34(+) monitoring commenced on D3. Apheresis commenced on D4. Comparison was with 22 historical controls (HC; lymphoma n=18, myeloma n=4; poor mobilizers n=4), mobilized with pegfilgrastim alone. Eight (67%) SP had PB CD34(+) count ⩽5 × 10(6)/L D3 post pegfilgrastim; all SP surpassed this threshold the morning after plerixafor. In SP, PBCD34(+) counts peaked D4 6/12 (50%), remaining ⩾5 × 10(6)/L for 4 days in 8/12 (67%). All SP successfully yielded target cell numbers (⩾2 × 10(6)/kg) within four aphereses. After maximum four aphereses, median total CD34+ yield was higher in SP than HC; 8.0 (range 2.4-12.9) vs 4.8 (0.4-14.0) × 10(6)/kg (P=0.04). Seven of twelve (58%) SP achieved target yield after one apheresis. Flow cytometry revealed no tumor cells in PB or apheresis product of SP. Plerixafor+pegfilgrastim was well tolerated with bone pain (n=2), diarrhoea (n=2) and facial paraesthesiae (n=3). Plerixafor+pegfilgrastim is a simple, safe and effective HSPC mobilization regimen in myeloma and lymphoma, in both poor and good mobilizers, and is superior to pegfilgrastim alone.

Rescue stem cell mobilization with plerixafor economizes leukapheresis in patients with multiple myeloma

While extensive data demonstrated that plerixafor improves stem cell harvest in difficult-to-mobilize patients, economic concerns limit a broader application. We retrospectively assessed the effect of an early plerixafor rescue regimen for mobilization in patients with multiple myeloma. Patients were intended for high-dose chemotherapy followed by autologous peripheral blood stem cell transplantation (ABSCT) and therefore received cyclophosphamide-based mobilization chemotherapy and consecutive stimulation with granulocyte colony-stimulating factor (G-CSF). Fifteen patients with poor stem cell harvest in the first leukapheresis session received plerixafor. Data were compared with a matched historic control group of 45 patients who also had a poor stem cell yield in the first apheresis session, but continued mobilization with G-CSF alone. Patients in the plerixafor group collected significantly more CD34+ cells in total (median 4.9 vs. 3.7 [range 1.6-14.1 vs. 1.1-8.0] × 10(6) CD34+ cells /kg bw; P < 0.05), and also more CD34+ cells per leukapheresis procedure (P < 0.001). Consequently, they required a significantly lower number of leukapheresis procedures to achieve the collection goal (median 2.0 vs. 4.0 [range 2-3 vs. 2-9] procedures; P < 0.001). The efficiency of the collected stem cells in terms of hematologic engraftment after ABSCT was found to be equal in both groups. These data demonstrate that rescue mobilization with plerixafor triggered by a low stem cell yield in the first leukapheresis session is effective. Although the actual economic benefit may vary depending on the local leukapheresis costs, the median saving of two leukapheresis procedures offsets most of the expenses for the substance in this setting. An exemplary cost calculation is provided to illustrate this effect.

The role of CXCR4 in highly malignant human gliomas biology: current knowledge and future directions

Given the extensive histomorphological heterogeneity of high-grade gliomas, in terms of extent of invasiveness, angiogenesis, and necrosis and the poor prognosis for patients despite the advancements made in therapeutic management. The identification of genes associated with these phenotypes will permit a better definition of glioma heterogeneity, which may ultimately lead to better treatment strategies. CXCR4, a cell surface chemokine receptor, is implicated in the growth, invasion, angiogenesis and metastasis in a wide range of malignant tumors, including gliomas. It is overexpressed in glioma cells according to tumor grade and in glioma tumor initiating cells. There have been various reports suggesting that CXCR4 is required for tumor proliferation, invasion, angiogenesis, and modulation of the immune response. It may also serve as a prognostic factor in characterizing subsets of glioblastoma multiforme, as patients with CXCR4-positive gliomas seem to have poorer prognosis after surgery. Aim of this review was to analyze the current literature on biological effects of CXCR4 activity and its role in glioma pathogenesis. A better understanding of CXCR4 pathway in glioma will lead to further investigation of CXCR4 as a novel putative therapeutic target.

Characterization of peripheral blood stem cell grafts mobilized by granulocyte colony-stimulating factor and plerixafor compared with granulocyte colony-stimulating factor alone

BACKGROUND AIMS

This study aimed to characterize the immune effectors contained in apheresis samples obtained from patients with grafts mobilized with plerixafor and granulocyte colony-stimulating factor (G-CSF) (P+G) compared with grafts mobilized with G-CSF alone (G).

METHODS

Aliquots of apheresis samples were obtained from 36 patients with malignant diseases after mobilization with G (n = 18) or P+G (n = 18). The phenotype and cytokine secretion profile of T cell and dendritic cell subsets were characterized by multicolor cytometry including intracellular cytokine staining.

RESULTS

In grafts collected after mobilization with P+G, there was a significantly higher percentage of CD3(+) T cells compared with samples collected after mobilization with G alone. On a functional level, a significant increase of interferon-γ and tumor necrosis factor-α secreting CD8(+) T cells was observed in the P+G group compared with the G group. CD4(+)Foxp3(+) regulatory T cells were similar in both groups but exhibited a lower expression of inducible costimulatory molecule and a significantly higher expression of CD127 in the P+G group. Myeloid dendritic cells (MDCs) and BDCA3(+) dendritic cells were similar in both groups. In contrast, plasmacytoid dendritic cells (PDCs) (CD123(+)BDCA2(+)HLA-DR(+)) were significantly increased in the P+G grafts, leading to a higher PDC-to-MDC ratio. PDCs mobilized by P+G displayed different functional markers--a higher percentage of ILT7(+) PDCs and decreased expression of CD86--suggesting a potential regulatory capacity of PDCs mobilized by P+G.

CONCLUSIONS

Grafts mobilized with P+G exhibited major different functional features compared with grafts mobilized with G alone, suggesting that such grafts may have an impact on patient outcome after autologous stem cell transplantation.