Long-Term Outcome after Autologous Stem Cell Transplantation with Adequate Peripheral Blood Stem Cell Mobilization Using Plerixafor and G-CSF in Poor Mobilizer Lymphoma and Myeloma Patients. Adv Hematol. 2011;2011:517561. [PMID: 22190942 PMCID: PMC3235426 DOI: 10.1155/2011/517561]

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.

O-Fucose and Fringe-modified NOTCH1 extracellular domain fragments as decoys to release niche-lodged hematopoietic progenitor cells

Successful hematopoietic progenitor cell (HPC) transplant therapy is improved by mobilizing HPCs from the bone marrow niche in donors. Notch receptor-ligand interactions are known to retain HPCs in the bone marrow, and neutralizing antibodies against Notch ligands, Jagged-1 or Delta-like ligand (DLL4), or NOTCH2 receptor potentiates HPC mobilization. Notch-ligand interactions are dependent on posttranslational modification of Notch receptors with O-fucose and are modulated by Fringe-mediated extension of O-fucose moieties. We previously reported that O-fucosylglycans on Notch are required for Notch receptor-ligand engagement controlling hematopoietic stem cell quiescence and retention in the marrow niche. Here, we generated recombinant fragments of NOTCH1 or NOTCH2 extracellular domain carrying the core ligand-binding regions (EGF11-13) either as unmodified forms or as O-fucosylglycan-modified forms. We found that the addition of O-fucose monosaccharide or the Fringe-extended forms of O-fucose to EGF11-13 showed substantial increases in binding to DLL4. Furthermore, the O-fucose and Fringe-extended NOTCH1 EGF11-13 protein displayed much stronger binding to DLL4 than the NOTCH2 counterpart. When assessed in an in vitro 3D osteoblastic niche model, we showed that the Fringe-extended NOTCH1 EGF11-13 fragment effectively released lodged HPC cells with a higher potency than the NOTCH2 blocking antibody. We concluded that O-fucose and Fringe-modified NOTCH1 EGF11-13 protein can be utilized as effective decoys for stem cell niche localized ligands to potentiate HPC egress and improve HPC collection for hematopoietic cell therapy.

Autograft cellular composition and outcome in myeloma patients: Results of the prospective multicenter GOA study

BACKGROUND

Autologous stem cell transplantation (auto-SCT) is a widely used treatment option in multiple myeloma (MM) patients. The optimal graft cellular composition is not known.

STUDY DESIGN AND METHODS

Autograft cellular composition was analyzed after freezing by flow cytometry in 127 MM patients participating in a prospective multicenter study. The impact of graft cellular composition on hematologic recovery and outcome after auto-SCT was evaluated.

RESULTS

A higher graft CD34⁺ cell content predicted faster platelet recovery after auto-SCT in both the short and long term. In patients with standard-risk cytogenetics, a higher graft CD34⁺ count (>2.5 × 10⁶ /kg) was linked with shorter progression-free survival (PFS; 28 vs. 46 months, p = 0.04), but there was no difference in overall survival (OS) (p = 0.53). In a multivariate model, a higher graft CD34⁺ CD133⁺ CD38^- (>0.065 × 10⁶ /kg, p = 0.009) and NK cell count (>2.5 × 10⁶ /kg, p = 0.026), lenalidomide maintenance and standard-risk cytogenetics predicted better PFS. In contrast, a higher CD34⁺ count (>2.5 × 10⁶ /kg, p = 0.015) predicted worse PFS. A very low CD3⁺ cell count (≤20 × 10⁶ /kg, p = 0.001) in the infused graft and high-risk cytogenetics remained predictive of worse OS.

CONCLUSIONS

Autograft cellular composition may impact outcome in MM patients after auto-SCT. More studies are needed to define optimal graft composition.

How old is too old? In vivo engraftment of human peripheral blood stem cells cryopreserved for up to 18 years - implications for clinical transplantation and stability programs

BACKGROUND

Peripheral blood stem cells (PBSC) are commonly cryopreserved awaiting clinical use for hematopoietic stem cell transplant. Long term cryopreservation is commonly defined as five years or longer, and limited data exists regarding how long PBSC can be cryopreserved and retain the ability to successfully engraft. Clinical programs, stem cell banks, and regulatory and accrediting agencies interested in product stability would benefit from such data. Thus, we assessed recovery and colony forming ability of PBSC following long-term cryopreservation as well as their ability to engraft in NOD/SCID/IL-2Rγ^null (NSG) mice.

AIM

To investigate the in vivo engraftment potential of long-term cryopreserved PBSC units.

METHODS

PBSC units which were collected and frozen using validated clinical protocols were obtained for research use from the Cellular Therapy Laboratory at Indiana University Health. These units were thawed in the Cellular Therapy Laboratory using clinical standards of practice, and the pre-freeze and post-thaw characteristics of the units were compared. Progenitor function was assessed using standard colony-forming assays. CD34-selected cells were transplanted into immunodeficient mice to assess stem cell function.

RESULTS

Ten PBSC units with mean of 17 years in cryopreservation (range 13.6-18.3 years) demonstrated a mean total cell recovery of 88% ± 12% (range 68%-110%) and post-thaw viability of 69% ± 17% (range 34%-86%). BFU-E growth was shown in 9 of 10 units and CFU-GM growth in 7 of 10 units post-thaw. Immunodeficient mice were transplanted with CD34-selected cells from four randomly chosen PBSC units. All mice demonstrated long-term engraftment at 12 wk with mean 34% ± 24% human CD45+ cells, and differentiation with presence of human CD19+, CD3+ and CD33+ cells. Harvested bone marrow from all mice demonstrated growth of erythroid and myeloid colonies.

CONCLUSION

We demonstrated engraftment of clinically-collected and thawed PBSC following cryopreservation up to 18 years in NSG mice, signifying likely successful clinical transplantation of PBSC following long-term cryopreservation.

Clinical outcomes of multiple myeloma patients who undergo autologous hematopoietic stem cell transplant with G-CSF or G-CSF and plerixafor mobilized grafts

Impact of Plerixafor (P) mobilized stem cells on immune reconstitution, such as absolute lymphocyte count at day 30 (ALC30), and on long-term outcomes of Multiple Myeloma (MM) patients undergoing autologous stem cell transplant (ASCT) has not been well established. We evaluated total of 469 patients mobilized with G-CSF (G) alone, and 141 patients mobilized with G-CSF plus plerixafor (G+ P). Patients only received plerixafor if they had peripheral blood CD34⁺   blood count <20/μL on first planned day of collection. Primary endpoint, ALC30, was 1.3 K/μL (range, 0.1-4.5) and 1.2 K/μL (range, 0.1-5.1) for G and G + P, respectively (P =. 61). The median PFS was 2.5 years (95% CI, 2.1-3.2) and 2.8 years (95% CI, 2.0-3.3) for G and G + P, respectively (HR: 1.13; 95% CI, 0.84-1.50; P = .42). The median OS was 6.1 years (95% CI, 4.6-NR) for G group compared to 3.7 years (95% CI, 3.2-NR) for the G + P group (HR: 1.64; 95% CI, 1.12-2.40; P = .01). The median follow-up time for OS was 2.53 years (95% CI, 2.13-2.99) and 1.59 years (95% CI, 1.17-2.02) for G and G+ P group, respectively. In this large retrospective analysis of MM patients mobilized with G-CSF vs G-CSF + P, there was no significant difference in lymphocyte recovery or PFS. There was an overall survival difference in patients who were poor mobilizers and could not be mobilized with G-CSF alone.

Mobilization potential of patients with lymphomas and multiple myeloma involved in autologous stem cell transplant

Introduction: High-dose chemotherapy by following autologous stem cell transplant (ASCT) is a standard treatment of multiple myeloma (MM), relapse of Hodgkin's lymphoma (HL) and non-Hodgkin's lymphomas (NHL). Monitoring of clinical and biochemical characteristics, as well as post-transplant parameters, all point to the importance of mobilization potential. Aim: To evaluate the association of early recovery of neutrophil granulocytes ≥0.5 x 109 /L after 11 days of transplantation (ANC500_11), platelets ≥20 x 109 /L after 13 days of transplantation (PLT20_13) with gender, age, duration of mobilization, as well as radiotherapy or chemotherapy, dose CD34+ cells in the apheresis product and therapeutic response. Material and Methods: The retrospective study included 100 patients, out of which 51 patients with MM, 27 with NHL and 22 with HL, in the period from November 2015, ending December 2018. Results: The median age of the patient was 53(20-67) years. According to the DSS, 69% were in IIIA, while 12.5% of patients were in the IIIB clinical stage. According to the Ann-Arbor staging 92% patients were in the II or III clinical stage. The mediana number of CD34+ cells in the apheresis product was 6.7×106 /kgBM. The median in all three mobilization attempts was 6 days. Engraftment is most often detected during the 11th day. In 78% of patients, mobilization was successful in the first attempt (≥2.0x106 /kgBM) among which 86% were MM and 69,4% of lymphomas (p<0.05). The impacts of age, the number of CD34+ cells in the peripheral blood and the duration of the mobilization did not show a significant difference (p>0.05) in relation to the recovery of ANC500_11 and PLT20_13. Conclusion: Satisfactory CD34+ cellular yield can be provided in the first mobilization attempt in most of the patients using of GCS-F, while in the further mobilization attempts plerixafor was necessery. As opposed to gender, age, duration of mobilization and therapeutic response have no impact on ANC500_11 and PLT20_13.

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.

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

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

Notch2 blockade enhances hematopoietic stem cell mobilization and homing

Despite use of newer approaches, some patients being considered for autologous hematopoietic cell transplantation (HCT) may only mobilize limited numbers of hematopoietic progenitor cells (HPCs) into blood, precluding use of the procedure, or being placed at increased risk of complications due to slow hematopoietic reconstitution. Developing more efficacious HPC mobilization regimens and strategies may enhance the mobilization process and improve patient outcome. Although Notch signaling is not essential for homeostasis of adult hematopoietic stem cells (HSCs), Notch-ligand adhesive interaction maintains HSC quiescence and niche retention. Using Notch receptor blocking antibodies, we report that Notch2 blockade, but not Notch1 blockade, sensitizes hematopoietic stem cells and progenitors (HSPCs) to mobilization stimuli and leads to enhanced egress from marrow to the periphery. Notch2 blockade leads to transient myeloid progenitor expansion without affecting HSC homeostasis and self-renewal. We show that transient Notch2 blockade or Notch2-loss in mice lacking Notch2 receptor lead to decreased CXCR4 expression by HSC but increased cell cycling with CXCR4 transcription being directly regulated by the Notch transcriptional protein RBPJ. In addition, we found that Notch2-blocked or Notch2-deficient marrow HSPCs show an increased homing to the marrow, while mobilized Notch2-blocked, but not Notch2-deficient stem cells and progenitors, displayed a competitive repopulating advantage and enhanced hematopoietic reconstitution. These findings suggest that blocking Notch2 combined with the current clinical regimen may further enhance HPC mobilization and improve engraftment during HCT.

Pharmacoeconomic impact of up-front use of plerixafor for autologous stem cell mobilization in patients with multiple myeloma

BACKGROUND AIMS

Stem cell collection can be a major component of overall cost of autologous stem cell transplantation (ASCT). Plerixafor is an effective agent for mobilization; however, it is often reserved for salvage therapy because of its high cost. We present data on the pharmacoeconomic impact of the use of plerixafor as an up-front mobilization in patients with multiple myeloma (MM).

METHODS

Patients with MM who underwent ASCT between January 2008 and April 2011 at the Mount Sinai Medical Center were reviewed retrospectively. In April 2010, practice changes were instituted for patients with MM to delay initiation of granulocyte-colony-stimulating factor (G-CSF) support from day 0 to day +5 and to add plerixafor to G-CSF as an up-front autologous mobilization. Targets of collection were 5-10 × 10(6) CD34(+) cells/kg.

RESULTS

Of 50 adults with MM who underwent ASCT, 25 received plerixafor/filgrastim and 25 received G-CSF alone as an up-front mobilization. Compared with the control, plerixafor mobilization yielded higher CD34(+) cell content (16.1 versus 8.4 × 10(6) CD34(+) cells/kg; P = 0.0007) and required fewer sessions of apheresis (1.9 versus 3.1; P = 0.0001). In the plerixafor group, the mean number of plerixafor doses required per patient was 1.8. Although the overall cost of medications was higher in the plerixafor group, the cost for blood products and overall cost of hospitalization were similar between the two groups.

CONCLUSIONS

Up-front use of plerixafor is an effective mobilization strategy in patients with MM and does not have a substantial pharmacoeconomic impact in overall cost of hospitalization combined with the apheresis procedure.

Plerixafor for mobilization of blood stem cells in autologous transplantation: an update

INTRODUCTION

About 99% of all autologous transplants are now performed with blood stem cells. G-CSF alone or combined with chemotherapy have been used to mobilize CD34(+) cells. Plerixafor is a novel drug used for mobilization purposes.

AREAS COVERED

We have evaluated recent data in regard to plerixafor use in predicted or proven poor mobilizers. In addition, we have looked for preemptive strategies to optimize the use of this expensive drug. Also cost-efficacy issues and effects of plerixafor on graft composition and post-transplant outcomes will be discussed.

EXPERT OPINION

Plerixafor added to G-CSF is superior than G-CSF alone for mobilization of CD34(+) cells. This combination is also efficient in patients who have failed a previous mobilization attempt with other methods or in patients with risk factors for poor mobilization. Addition of plerixafor to G-CSF or chemotherapy plus G-CSF mobilization in patients who appear to mobilize poorly is under active investigation and algorithms for a preemptive use of this expensive agent have been proposed. Grafts collected after plerixafor appear to contain more lymphoid cells than the grafts collected without it. Whether this affects post-transplant outcomes such as immune reconstitution and risk of relapse needs to be evaluated.