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ABSTRACT: Preapheresis peripheral blood (PB) CD34(+) cell count is a strong predictor of hematopoietic stem cell (HSC) mobilization and is routinely used to optimize the timing, cost, and success of HSC collection in patients with multiple myeloma. However, a uniform PB CD34(+) cell count that predicts mobilization failure has not been defined, resulting in the development of institute-specific algorithms for mobilization, particularly regarding the decision of when to use the novel stem cell mobilization agent plerixafor. In this post hoc analysis, we evaluated the mobilization efficacy of plerixafor plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in patients with multiple myeloma, stratified by preapheresis PB CD34(+) cell count: <10, <15, <20, and ≥20 cells/μL. Regardless of the PB CD34(+) cell count, the total yield of CD34(+) cells from apheresis was significantly higher in the plerixafor group than in the placebo group, and significantly more patients in the plerixafor group collected the minimum (≥2 × 10(6) cells/kg) and optimum (≥6 × 10(6) cells/kg) stem cell yields on each day of apheresis. As a corollary, the greater stem cell collection in plerixafor-treated patients resulted in the need for significantly fewer days of apheresis to reach minimum and optimum cell doses across all cell count groups. For all CD34(+) cell count groups, the proportion of patients proceeding to transplantation and the median time to platelet and neutrophil engraftment were similar in the plerixafor and placebo groups. Our findings demonstrate that in patients with multiple myeloma who might be predicted to fail mobilization based on low PB CD34(+) cell count, the addition of plerixafor to G-CSF allows for collection of the minimal and optimal cell doses in a greater proportion of patients compared with G-CSF alone. In addition, plerixafor plus G-CSF significantly improves the likelihood of optimal HSC collection in patients with higher preapheresis PB CD34(+) cell counts (≥20 cells/μL) compared with placebo plus G-CSF. Collectively, this analysis of predicted poor mobilizers validates the superiority of plerixafor plus G-CSF compared with G-CSF alone, which had been demonstrated previously in the overall patient population.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 06/2012; 18(10):1564-72. · 3.15 Impact Factor
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Renato Skerlj, Gary Bridger,
Yuanxi Zhou,
Elyse Bourque,
Ernest McEachern,
Jonathan Langille,
Curtis Harwig,
Duane Veale,
Wen Yang,
Tongshong Li, [......],
Michael Sartori,
Markus Metz,
Renee Mosi,
Kim Nelson,
Veronique Bodart,
Rebecca Wong,
Simon Fricker,
Ron Mac Farland,
Dana Huskens,
Dominique Schols
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ABSTRACT: A series of CCR5 antagonists were optimized for potent inhibition of R5 HIV-1 replication in peripheral blood mononuclear cells. Compounds that met acceptable ADME criteria, selectivity, human plasma protein binding, potency shift in the presence of α-glycoprotein were evaluated in rat and dog pharmacokinetics.
Bioorganic & medicinal chemistry letters 12/2011; 21(23):6950-4. · 2.65 Impact Factor
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Renato Skerlj, Gary Bridger,
Ernest McEachern,
Curtis Harwig,
Chris Smith,
Alan Kaller,
Duane Veale,
Helen Yee,
Krystyna Skupinska,
Rossana Wauthy,
Letian Wang,
Ian Baird,
Yongbao Zhu,
Kate Burrage,
Wen Yang,
Michael Sartori,
Dana Huskens,
Erik De Clercq,
Dominique Schols
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ABSTRACT: A novel series of CXCR4 antagonists were identified based on the substantial redesign of AMD070. These compounds possessed potent anti-HIV-1 activity and showed excellent pharmacokinetics in rat and dog.
Bioorganic & medicinal chemistry letters 03/2011; 21(5):1414-8. · 2.65 Impact Factor
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Renato Skerlj, Gary Bridger,
Yuanxi Zhou,
Elyse Bourque,
Jonathan Langille,
Maria Di Fluri,
David Bogucki,
Wen Yang,
Tongshuang Li,
Letian Wang,
Susan Nan,
Ian Baird,
Markus Metz,
Marilyn Darkes,
Jean Labrecque,
Gloria Lau,
Simon Fricker,
Dana Huskens,
Dominique Schols
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ABSTRACT: A novel series of CCR5 antagonists were identified based on the redesign of Schering C. An SAR was established based on inhibition of CCR5 (RANTES) binding and these compounds exhibited potent inhibition of R5 HIV-1 replication in peripheral blood mononuclear cells.
Bioorganic & medicinal chemistry letters 02/2011; 21(8):2450-5. · 2.65 Impact Factor
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Renato Skerlj, Gary Bridger,
Ernie McEachern,
Curtis Harwig,
Chris Smith,
Trevor Wilson,
Duane Veale,
Helen Yee,
Jason Crawford,
Krystyna Skupinska,
Rossana Wauthy,
Wen Yang,
Yongbao Zhu,
David Bogucki,
Maria Di Fluri,
Jonathon Langille,
Dana Huskens,
Erik De Clercq,
Dominique Schols
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ABSTRACT: An early lead from the AMD070 program was optimized and a structure-activity relationship was developed for a novel series of heterocyclic containing compounds. Potent CXCR4 antagonists were identified based on anti-HIV-1 activity and Ca(2+) flux inhibition that displayed good pharmacokinetics in rat and dog.
Bioorganic & medicinal chemistry letters 01/2011; 21(1):262-6. · 2.65 Impact Factor
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ABSTRACT: Autologous hematopoietic stem cell transplantation (ASCT) is an established treatment for patients with hematologic malignancies, yet the impact of transplanted CD34(+) cell dose on clinical outcomes is unresolved. We conducted post hoc analyses of transplanted CD34(+) cell dose and hematopoietic recovery following ASCT in 438 patients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), using data from 2 multicenter phase 3 clinical studies that compared plerixafor plus granulocyte-colony stimulating factor (G-CSF) versus placebo plus G-CSF as stem cell mobilization regimens. Days to engraftment and the proportion of patients who reached predetermined blood count thresholds were compared across 3 CD34(+) cell dose levels: 2-4 × 10(6) cells/kg, 4-6 × 10(6) cells/kg, and >6 × 10(6) cells/kg, regardless of mobilization treatment. Short-term neutrophil and platelet engraftment times were similar regardless of cell dose. A significant linear trend was observed between transplanted CD34(+) cell dose and the proportion of patients with platelet count >150 × 10(9)/L at 100 days (P < .001), 6 months (P = .026), and 12 months (P = .020) in patients with NHL, and at 100 days in patients with MM (P = .004). A linear trend was also observed between transplanted cell dose and the proportion of patients with platelet count >100 × 10(9)/L at 100 days (P < .001) and 6 months (P = .023) in patients with NHL. A higher cell dose was associated with a lower percentage of NHL patients requiring red blood cell transfusions (P = .006). Our analyses confirm previous findings that transplanted CD34(+) cell dose may be associated with better long-term platelet recovery after ASCT.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 11/2010; 17(8):1146-53. · 3.15 Impact Factor
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Blood 01/2010; 115(4):916-7. · 9.90 Impact Factor
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ABSTRACT: Pharmacological manipulation of CXCR4 has proven clinically useful for mobilization of stem and progenitor cells and in several preclinical models of disease. It is a key component in the localization of leukocytes and stem cells. For patients with multiple myeloma and non-Hodgkin's Lymphoma, treatment with plerixafor, an inhibitor of CXCL12 binding to CXCR4, plus G-CSF mobilizes stem cells for autologous transplantation to a greater degree than the treatment with G-CSF alone, and in some cases when patients could not be mobilized with cytokines, chemotherapy, or the combination. Stem cells from healthy donors mobilized with single agent plerixafor have been used for allogeneic transplantation in acute myelogenous leukemia (AML) patients, although this is still in the early phase of clinical development. Plerixafor is also undergoing evaluation to mobilize tumor cells in patients with AML and chronic lymphocytic leukemia (CLL) to enhance the effectiveness of chemotherapy regimens. Plerixafor's effect on neutrophils may also restore circulating neutrophil counts to normal levels in patients with chronic neutropenias such as in WHIMs syndrome. Other areas where inhibition of CXCR4 may be useful based upon preclinical or clinical data include peripheral vascular disease, autoimmune diseases such as rheumatoid arthritis, pulmonary inflammation, and HIV.
Current topics in microbiology and immunology 01/2010; 341:173-91. · 4.93 Impact Factor
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ABSTRACT: In a phase 3 multicenter, randomized, double-blinded, placebo-controlled study of 298 patients with non-Hodgkin lymphoma (NHL), granulocyte colony-stimulating factor (G-CSF) plus plerixafor increased the proportion of patients who mobilized >or=5 x 10(6) CD34(+) hematopoietic stem cells (HSCs)/kg compared with placebo plus G-CSF (P < .001). Patients in either study arm who failed mobilization (< 0.8 x 10(6) CD34(+) cells/kg in 2 collections or <2 x 10(6) CD34(+) cells/kg in 4 collections) were eligible to enter the opened-label rescue protocol. Following a 7-day minimum rest period, these patients received G-CSF (10 microg/kg/day) for 4 days, followed by daily plerixafor (0.24 mg/kg) plus G-CSF and apheresis for up to 4 days. Of the 68 patients failing initial mobilization (plerixafor, n = 11; placebo, n = 57), 62 patients (91%) entered the rescue procedure (plerixafor, n = 10; placebo, n = 52). Four of 10 patients (40%) from the plerixafor group and 33 of 52 (63%) from the placebo group mobilized sufficient CD34(+) cells (>or= 2 x 10(6) cells/kg) for transplantation from the rescue mobilization alone (P = .11). Engraftment of neutrophils (11 days) and platelets (20 days) was similar to that in patients who did not fail initial mobilization, and all patients had durable grafts at the 12-month follow-up. Common plerixafor-related adverse events (AEs) included mild gastrointestinal (GI) effects and injection site reactions. There were no drug-related serious AEs. These data support that plerixafor plus G-CSF can safely and effectively remobilize patients with NHL who have failed previous mobilization.
Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation 12/2009; 15(12):1578-86. · 3.15 Impact Factor
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ABSTRACT: This study evaluates the safety and efficacy of plerixafor (AMD3100), a CXCR4 antagonist, in mobilizing hematopoietic stem cells for autologous stem-cell transplantation in non-Hodgkin's lymphoma (NHL) patients.
This is a phase III, multicenter, randomized (1:1), double-blind, placebo-controlled study. Patients with non-Hodgkin's lymphoma requiring an autologous hematopoietic stem-cell transplantation in first or second complete or partial remission were eligible. Patients received granulocyte colony-stimulating factor (G-CSF; 10 microg/kg) subcutaneously daily for up to 8 days. Beginning on evening of day 4 and continuing daily for up to 4 days, patients received either plerixafor (240 microg/kg) or placebo subcutaneously. Starting on day 5, patients began daily apheresis for up to 4 days or until > or = 5 x 10(6) CD34+ cells/kg were collected. The primary end point was the percentage of patients who collected > or = 5 x 10(6) CD34+ cells/kg in 4 or fewer apheresis days.
This report presents all data for all patients (n = 298) through 12 months follow-up. Eighty-nine (59%) of 150 patients in the plerixafor group and 29 (20%) of 148 patients in the placebo group met the primary end point (P < .001). One hundred thirty-five patients (90%) in plerixafor group and 82 patients (55%) in placebo group underwent transplantation after initial mobilization. Median time to engraftment was similar in both groups. The most common plerixafor-associated adverse events were GI disorders and injection site reactions.
Plerixafor and G-CSF were well tolerated and resulted in a significantly higher proportion of patients with non-Hodgkin's lymphoma achieving the optimal CD34+ cell target for transplantation in fewer apheresis days, compared with G-CSF alone.
Journal of Clinical Oncology 08/2009; 27(28):4767-73. · 18.37 Impact Factor
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John F DiPersio,
Edward A Stadtmauer,
Auayporn Nademanee,
Ivana N M Micallef,
Patrick J Stiff,
Jonathan L Kaufman,
Richard T Maziarz,
Chitra Hosing,
Stefan Früehauf,
Mitchell Horwitz,
Dennis Cooper, Gary Bridger,
Gary Calandra
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ABSTRACT: This phase 3, multicenter, randomized (1:1), double-blind, placebo-controlled study evaluated the safety and efficacy of plerixafor with granulocyte colony-stimulating factor (G-CSF) in mobilizing hematopoietic stem cells in patients with multiple myeloma. Patients received G-CSF (10 microg/kg) subcutaneously daily for up to 8 days. Beginning on day 4 and continuing daily for up to 4 days, patients received either plerixafor (240 microg/kg) or placebo subcutaneously. Starting on day 5, patients began daily apheresis for up to 4 days or until more than or equal to 6 x 10(6) CD34(+) cells/kg were collected. The primary endpoint was the percentage of patients who collected more than or equal to 6 x 10(6) CD34(+) cells/kg in less than or equal to 2 aphereses. A total of 106 of 148 (71.6%) patients in the plerixafor group and 53 of 154 (34.4%) patients in the placebo group met the primary endpoint (P < .001). A total of 54% of plerixafor-treated patients reached target after one apheresis, whereas 56% of the placebo-treated patients required 4 aphereses to reach target. The most common adverse events related to plerixafor were gastrointestinal disorders and injection site reactions. Plerixafor and G-CSF were well tolerated, and significantly more patients collected the optimal CD34(+) cell/kg target for transplantation earlier compared with G-CSF alone. This study is registered at www.clinicaltrials.gov as #NCT00103662.
Blood 04/2009; 113(23):5720-6. · 9.90 Impact Factor
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ABSTRACT: The X4 Antagonist Concept Trial investigates the safety and antiviral activity of AMD11070, a potent inhibitor of X4-tropic human immunodeficiency virus (HIV) in vitro in HIV-infected patients harboring X4-tropic virus.
Patients enrolled in the study had an X4 virus population 2000 relative luminescence units (rlu; by the Monogram Trofile Assay) and an HIV-1 RNA level 5000 copies/mL. Patients received AMD11070 monotherapy for 10 days. Coreceptor tropism, plasma HIV-1 RNA level, and CD4 cell count were measured at study entry, on day 5, and on day 10. Daily predose and serial samples on the last day of treatment were obtained for determination of plasma AMD11070 concentration.
Ten patients were given AMD11070 monotherapy (200 mg to 8 patients and 100 mg to 2 patients) twice daily for 10 days. The median baseline CD4 cell count was 160 cells/mm(3), and the median HIV-1 RNA level was 91,447 copies/mL. Four of 9 evaluable patients achieved a reduction in X4 virus population of >or= rlu. The median change in X4 virus population at the end of treatment was -0.22 log(10) rlu (range, -1.90 to 0.23 log(10) rlu). Three of 4 patients who responded to therapy showed a tropism shift from dual- or mixed-tropic viruses to exclusively R5 virus by day 10. There were no drug-related serious adverse events, adverse events of greater than grade 2, or laboratory abnormalities.
These results demonstrate the activity of AMD11070, the first oral CXCR4 antagonist, against X4-tropic HIV-1. The drug was well tolerated, with no serious safety concerns. AMD11070 is on clinical hold because of histologic changes to the liver observed in long-term animal studies; additional preclinical safety assessments are pending.
Clinical Infectious Diseases 03/2009; 48(6):798-805. · 9.15 Impact Factor
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Bruno Nervi,
Pablo Ramirez,
Michael P Rettig,
Geoffrey L Uy,
Matthew S Holt,
Julie K Ritchey,
Julie L Prior,
David Piwnica-Worms, Gary Bridger,
Timothy J Ley,
John F DiPersio
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ABSTRACT: The CXCR4-SDF-1 axis plays a central role in the trafficking and retention of normal and malignant stem cells in the bone marrow (BM) microenvironment. Here, we used a mouse model of acute promyelocytic leukemia (APL) and a small molecule competitive antagonist of CXCR4, AMD3100, to examine the interaction of mouse APL cells with the BM microenvironment. APL cells from a murine cathepsin G-PML-RARalpha knockin mouse were genetically modified with firefly luciferase (APL(luc)) to allow tracking by bioluminescence imaging. Coculture of APL(luc) cells with M2-10B4 stromal cells protected the leukemia cells from chemotherapy-induced apoptosis in vitro. Upon injection into syngeneic recipients, APL(luc) cells rapidly migrated to the BM followed by egress to the spleen then to the peripheral blood with death due to leukostasis by day 15. Administration of AMD3100 to leukemic mice induced a 1.6-fold increase in total leukocytes and a 9-fold increase of circulating APL blast counts, which peak at 3 hours and return to baseline by 12 hours. Treatment of leukemic mice with chemotherapy plus AMD3100 resulted in decreased tumor burden and improved overall survival compared with mice treated with chemotherapy alone. These studies provide a proof-of-principle for directing therapy to the critical tethers that promote AML-niche interactions.
Blood 01/2009; 113(24):6206-14. · 9.90 Impact Factor
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ABSTRACT: CXC chemokine receptor (CXCR)4 is an HIV coreceptor and a chemokine receptor that plays an important role in several physiological and pathological processes, including hematopoiesis, leukocyte homing and trafficking, metastasis, and angiogenesis. This receptor belongs to the class A family of G protein-coupled receptors and is a validated target for the development of a new class of antiretroviral therapeutics. This study compares the interactions of three structurally diverse small-molecule CXCR4 inhibitors with the receptor and is the first report of the molecular interactions of the nonmacrocyclic CXCR4 inhibitor (S)-N'-(1H-benzimidazol-2-ylmethyl)-N'-(5,6,7,8-tetrahydroquinolin-8-yl)butene-1,4-diamine (AMD11070). Fourteen CXCR4 single-site mutants representing amino acid residues that span the entire putative ligand binding pocket were used in this study. These mutants were used in binding studies to examine how each single-site mutation affected the ability of the inhibitors to compete with (125)I-stromal-derived factor-1alpha binding. Our data suggest that these CXCR4 inhibitors bind to overlapping but not identical amino acid residues in the transmembrane regions of the receptor. In addition, our results identified amino acid residues that are involved in unique interactions with two of the CXCR4 inhibitors studied. These data suggest an extended binding pocket in the transmembrane regions close to the second extracellular loop of the receptor. Based on site-directed mutagenesis and molecular modeling, several potential binding modes were proposed for each inhibitor. These mechanistic studies might prove to be useful for the development of future generations of CXCR4 inhibitors with improved clinical pharmacology and safety profiles.
Molecular pharmacology 10/2008; 74(6):1485-95. · 4.53 Impact Factor
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Steven M Devine,
Ravi Vij,
Michael Rettig,
Laura Todt,
Kiley McGlauchlen,
Nicholas Fisher,
Hollie Devine,
Daniel C Link,
Gary Calandra, Gary Bridger,
Peter Westervelt,
John F Dipersio
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ABSTRACT: Allografts from HLA-matched sibling donors were mobilized and collected without granulocyte colony-stimulating factor (G-CSF) using AMD3100, a direct antagonist of CXCR4/stromal-derived factor 1 (SDF-1/CXCL12). Donors (N = 25) were treated with AMD3100 at a dose of 240 mug/kg by subcutaneous injection, and leukapheresis was then initiated just 4 hours later. Two-thirds of the donors collected an allograft with a CD34(+) cell dose sufficient for transplantation after just one dose of AMD3100. No donor experienced more than grade 1 toxicity. After a myeloablative regimen, 20 patients with hematologic malignancies received allografts collected after AMD3100 alone. All patients engrafted neutrophils (median day 10) and platelets (median day 12) promptly. Acute graft-versus-host disease (GVHD) grades 2 through 4 occurred in 35% of patients. One patient died due to complications related to acute GVHD. No unexpected adverse events were observed in any of the recipients. All 14 patients surviving in remission have robust trilineage hematopoiesis and are transfusion-free with a median follow-up of 277 days (range, 139-964 days). Direct antagonism of CXCR4 by AMD3100 may provide a more rapid and possibly less toxic and cumbersome alternative to traditional G-CSF-based mobilization in normal donors. This trial was registered as no. NCT00241358 at www.ClinicalTrials.gov.
Blood 05/2008; 112(4):990-8. · 9.90 Impact Factor
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Anne Faber,
Christoph Roderburg,
Frederik Wein,
Rainer Saffrich,
Anja Seckinger,
Kerstin Horsch,
Anke Diehlmann,
Donald Wong, Gary Bridger,
Volker Eckstein,
Anthony D Ho,
Wolfgang Wagner
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ABSTRACT: Stromal cell-derived factor-1alpha (SDF-1alpha) has pleiotropic effects on hematopoietic progenitor cells (HPCs). We have monitored podia formation, migration, proliferation, and cell-cell adhesion of human HPC under the influence of SDF-1alpha, a peptide agonist of CXCR4 (CTCE-0214), a peptide antagonist (CTCE-9908), and a nonpeptide antagonist (AMD3100). Whereas SDF-1alpha induced migration of CD34(+) cells in a dose-dependent manner, CTCE-0214, CTCE-9908, and AMD3100 did not induce chemotaxis in this concentration range albeit the peptides CTCE-0214 and CTCE-9908 increased podia formation. Cell-cell adhesion of HPC to human mesenchymal stromal cells was impaired by the addition of SDF-1alpha, CTCE-0214, and AMD3100. Proliferation was not affected by SDF-1alpha or its analogs. Surface antigen detection of CXCR4 was reduced upon treatment with SDF-1alpha or AMD3100 and it was enhanced by CTCE-9908. Despite the fact that all these molecules target the same CXCR4 receptor, CXCR4 agonists and antagonists have selective effects on different functions of the natural molecule.
Journal of Biomedicine and Biotechnology 02/2007; 2007(3):26065. · 2.44 Impact Factor
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Stefan Fruehauf,
Timon Seeger,
Patrick Maier,
Li Li,
Stephan Weinhardt,
Stephanie Laufs,
Wolfgang Wagner,
Volker Eckstein, Gary Bridger,
Gary Calandra,
Frederick Wenz,
W Jens Zeller,
Hartmut Goldschmidt,
Anthony D Ho
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ABSTRACT: AMD3100 is a new CXCR4 antagonist that induces a rapid release of hematopoietic progenitors from the bone marrow to the peripheral blood. We conducted a clinical study where patients with multiple myeloma and non-Hodgkin's lymphoma were treated with AMD3100 (A) to increase the number of peripheral blood progenitor cells (PBPCs) when given a mobilization regimen of granulocyte colony-stimulating factor (G-CSF, G). Because experimental data suggest that A+G-mobilized PBPCs are functionally different from G-mobilized PBPCs, we were interested in an intraindividual comparison of the gene expression profile of CD34+ cells in the two different settings.
To this end peripheral blood CD34+ cells of three patients (three G, three A+G samples) were isolated by immunomagnetic followed by flow cytometric sorting to a purity of >99%. Total RNA was purified. Differentially expressed genes were analyzed by using the Affymetrix GeneChip Human Genome U133 Plus2.0 and the software package Micro Array Solutions 1.3 (SAS Institute Inc.).
We found a pattern of unanimously higher (81 genes, log2 ratio > 0.5; p < 0.0001) or lower (29 genes, log2 ratio < -0.4; p < 0.0001) expressed genes in the A+G-mobilized vs G-mobilized CD34+ PBPCs. Significant changes of four selected genes noted in the microarray analysis were validated by quantitative real-time polymerase chain reaction. Genes were grouped according to gene function. Only increased expression was found in the categories antiapoptosis (e.g., MPO, HSPA1B), cell cycle (e.g., MS4A3, RRM2), replication/DNA repair (e.g., MPO, HSPA1B), cell motility (e.g., TNFSF4, HMMR), and oxygen transport. Decreased expression occurred in the proapoptosis gene group (e.g., MDA5, BCL10). CXCR4 receptor gene expression itself was significantly 1.5-fold higher in the A+G vs G group.
We conclude that A+G-mobilized CD34+ PBPCs express significantly higher amounts of genes that potentially promote superior engraftment after myeloablative therapy than G-mobilized CD34+ PBPCs.
Experimental Hematology 09/2006; 34(8):1052-9. · 2.90 Impact Factor
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ABSTRACT: AMD3100, a bicyclam antagonist of the chemokine receptor CXCR4, has been shown to induce rapid mobilization of CD34(+) hematopoietic cells in mice, dogs, and humans, offering an alternative to G-CSF mobilization of peripheral-blood hematopoietic stem cells. In this study, AMD3100-mobilized CD34(+) cells were phenotypically analyzed, marked with Neo(R)-containing retroviral vectors, and subsequently transplanted into myeloablated rhesus macaques. We show engraftment of transduced AMD3100-mobilized CD34(+) cells with Neo(R) gene marked myeloid and lymphoid cells up to 32 months after transplantation, demonstrating the ability of AMD3100 to mobilize true long-term repopulating hematopoietic stem cells. More AMD3100-mobilized CD34(+) cells are in the G(1) phase of the cell cycle and more cells express CXCR4 and VLA-4 compared with G-CSF-mobilized CD34(+) cells. In vivo gene marking levels obtained with AMD3100-mobilized CD34(+) cells were better than those obtained using CD34(+) cells mobilized with G-CSF alone. Overall, these results indicate that AMD3100 mobilizes a population of hematopoietic stem cells with intrinsic characteristics different from those of hematopoietic stem cells mobilized with G-CSF, suggesting fundamental differences in the mechanism of AMD3100-mediated and G-CSF-mediated hematopoietic stem cell mobilization. Thus, AMD3100-mobilized CD34(+) cells represent an alternative source of hematopoietic stem cells for clinical stem cell transplantation and genetic manipulation with integrating retroviral vectors.
Blood 06/2006; 107(9):3772-8. · 9.90 Impact Factor
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ABSTRACT: Current myeloablative conditioning regimens for hematopoietic stem cell (HSC) transplantation are associated with significant morbidity and mortality. Thus, alternative strategies to promote engraftment of infused HSCs with increased safety warrant investigation. Using parabiotic mice, we determined that, after mobilization with AMD3100 (a CXCR4 antagonist), HSCs exited from marrow, transited blood, and engrafted in open niches in partner marrow. We then hypothesized that mobilization before transplantation might vacate niches and improve HSC engraftment. When PeP3(b) mice were treated with AMD3100 at 2 hours before the transplantation of 4 x 10(7) marrow cells, donor cell engraftment was higher (4.6% +/- 1.1%) than in control animals (no AMD3100; 1.0% +/- 0.24%, P < .001). When mice received weekly injections of AMD3100 on 3 consecutive weeks and marrow cells were transplanted 2 hours after each mobilization, donor cell engraftment further increased (9.1% +/- 1.7%, P = .001). In contrast, in similar experiments with Balb/cByJ mice that mobilize poorly, there was no difference between the donor cell engraftment of AMD3100-treated and control recipients. These results indicate that the number of available niches regulates the number of HSCs. In addition, mobilization with AMD3100 may provide a safer preparative approach for HSC transplantation in genetic and other nonmalignant disorders.
Blood 05/2006; 107(9):3764-71. · 9.90 Impact Factor
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ABSTRACT: Peripheral-blood mononuclear cells (PBMCs) mobilized with AMD3100, a CXCR4 antagonist, combined with granulocyte colony-stimulating factor (G-CSF) have reconstituted autologous hematopoiesis in cancer patients following myeloablative conditioning. The engraftment potential of PBMCs mobilized with AMD3100 alone, however, has remained unproven. We therefore studied AMD3100-mobilized PBMCs in a canine model. Four dogs received 920 cGy total body irradiation (TBI) before infusion of autologous AMD3100-mobilized PBMCs (median CD34 cell count, 3.9 x 10(6)/kg). Neutrophil (> 0.5 x 10(9)/L [500/microL]) and platelet (> 20 x 10(9)/L [> 20 000/microL]) recoveries occurred at medians of 9 (range, 7-10) days and 25 (range, 23-38) days, respectively, after TBI, and all dogs had normal marrow function at 1 year after transplantation. To evaluate the long-term engraftment potential of AMD3100-mobilized PBMCs, 5 dogs were given 920 cGy TBI followed by infusion of AMD3100-mobilized PBMCs (median CD34 cell dose, 4.7 x 10(6)/kg) from their dog leukocyte antigen (DLA)-identical littermates. Neutrophil and platelet recoveries occurred at medians of 8 (range, 8-10) days and 26 (range, 26-37) days, respectively, after TBI. With a median follow-up of 53 (range, 33-61) weeks, recipients' marrow function was normal, and blood-donor chimerism levels were 97% to 100%. In summary, both autologous and allogeneic AMD3100-mobilized PBMCs led to prompt and durable engraftment in dogs after 920 cGy TBI.
Blood 01/2006; 106(12):4002-8. · 9.90 Impact Factor
