Granulocyte Colony-stimulating Factor Regimen Research Articles

Survivors of polymicrobial sepsis are refractory to G-CSF-induced emergency myelopoiesis and hematopoietic stem and progenitor cell mobilization

Sepsis survivors exhibit immune dysfunction, hematological changes, and increased risk of infection. The long-term impacts of sepsis on hematopoiesis were analyzed using a surgical model of murine sepsis, resulting in 50% survival. During acute disease, phenotypic hematopoietic stem and progenitor cells (HSPCs) were reduced in the bone marrow (BM), concomitant with increased myeloid colony-forming units and extramedullary hematopoiesis. Upon recovery, BM HSPCs were increased and exhibited normal function in the context of transplantation. To evaluate hematopoietic responses in sepsis survivors, we treated recovered sham and cecal ligation and puncture mice with a mobilizing regimen of granulocyte colony-stimulating factor (G-CSF) at day 20 post-surgery. Sepsis survivors failed to undergo emergency myelopoiesis and HSPC mobilization in response to G-CSF administration. G-CSF is produced in response to acute infection and injury to expedite the production of innate immune cells; therefore, our findings contribute to a new understanding of how sepsis predisposes to subsequent infection.

On-demand plerixafor added to high-dose cyclophosphamide and pegylated recombinant human granulocyte colony-stimulating factor in the mobilization of patients with multiple myeloma: a treatment with high effectiveness, convenient, and affordable cost.

The combination of high-dose cyclophosphamide (HD-Cy) (3g/m2) plus granulocyte colony-stimulating factor (G-CSF) and on-demand plerixafor (PXF) has been considered an effective mobilization regimen of patients with multiple myeloma(MM). However, the daily multi-injection regimen of G-CSF poses challenges. This study delves into the efficiency and cost implications of a novel approach, using HD-Cy alongside pegylated G-CSF (PEG G-CSF) and on-demand PXF. Unlike G-CSF, which necessitates daily injections, the half-life of PEG G-CSF extended allows for a single injection. A retrospective analysis was conducted on 350 MM patients, which were categorized based on their mobilization regimens: Cy+PEG G-CSF+/-PXF (n=66), Cy+PEG G-CSF (n=91), Cy+ G-CSF (n=169), and G-CSF+PXF (n=24). Mobilization with Cy+PEG G-CSF+/-PXF(8.79)yielded a notably higher median CD34+ cell count compared to the other regimens: Cy+PEG G-CSF(4.96), Cy+G-CSF (4.65), and G-CSF+PXF (2.99) (P<0.001). The percentage of patients who achieved >6×106/kg CD34+ cells was significantly higher in the Cy+PEG G-CSF+/-PXF group (77.3%) than in the other mobilization regimens: Cy+PEG G-CSF (41.8%), Cy+ G-CSF (37.3%), and G-CSF+PXF (8.3%) (P<0.001). From a cost perspective, the Cy+PEG G-CSF+/-PXF approach was more economical than the G-CSF+PXF strategy but was marginally costlier than the other two methods. A multivariate assessment highlighted that the combination of Cy+PEG G-CSF with on-demand PXF had a superior potential to achieve the desired harvest (6×106/kg) compared to the Cy+PEG G-CSF protocol without PXF. The incremental cost-effectiveness ratio for each 1% increase in the probability of achieving a successful optimal harvest was $ 97.02 per patient. The incidence of neutropenic fever was 3.0% in the Cy+PEG G-CSF+/-PXF group. The combination of on-demand PXF with HD-Cy and PEG G-CSF offers a cost-effective approach with a high mobilization success rate, manageable side effects, and the convenience of fewer injections. It stands as a promising mobilization strategy for MM patients.

Primary Prevention of Neutropenia by Empegfilgrastim in Patients with Advanced Stages of Classical Hodgkin Lymphoma Treated with Intensive First-Line Chemotherapy with a Modified 6-Cycle Program EACODD-14 Under the Protocol “LKh-Rossiya-1”

Aim. To assess the efficacy of a long-acting form of the granulocyte colony-stimulating factor (G-CSF) empegfilgrastim in primary prevention of neutropenia in patients with advanced stages of classical Hodgkin lymphoma (cHL) who received intensive chemotherapy with reduced inter-cycle interval under the protocol “LKh-Rossiya-1”.&#x0D; Materials &amp; Methods. The study enrolled 35 patients with newly diagnosed cHL. All patients had advanced stages (IIB X/Е and III/IV) of the disease. They were treated at the NI Pirogov National Medical and Surgical Center from March 2013 to August 2022. The primary prevention of neutropenia by long-acting G-CSF (empegfilgrastim) was administered to 21 patients under the protocol “LKh-Rossiya-1”. They received 6 chemotherapy cycles of modified EACODD-14, in total 126 cycles. The control group consisted of 14 patients who received 6 ЕАСОРР-14 chemotherapy cycles (in total 84 cycles) with dacarbazine as substitution for procarbazine. In the control group, the primary prevention of neutropenia was carried out using discrete G-CSF (filgrastim). The median (range) follow-up in the main (n = 21) and control (n = 14) groups was 18 (5–36) and 39 (29–116) months, respectively. The treatment efficacy was assessed based on PET-CT in 31 patients and on CT in 4 patients.&#x0D; Results. By the end of chemotherapy, complete metabolic response was achieved in 28 (80 %) out of 35 patients (95 % in the EACODD-14 and 73 % in ЕАСОРР-14 groups). In 6 (17 %) patients, partial remission was confirmed only by CT scan, and in 1 (3 %) patient, PET/CT showed stabilization. After consolidation radiotherapy, complete remission was reported in all 35 patients. Both groups received the full chemotherapy program per protocol. Without a violation of G-CSF regimen, the EACODD-14 group received 121 (96 %) cycles out of those 126 planned, whereas the ЕАСОРР-14 group received all 84 cycles per protocol. Full implementation of 107 (88.4 %) cycles in the first group and 24 (29 %) cycles in the second group was achieved in 12 (57 %) and 5 (36 %) patients, respectively (p &lt; 0.001). Neutropenia grade 4 was more often identified in filgrastim than in empegfilgrastim recipients (57 % vs. 19 %; p &lt; 0.05) and in a larger number of cycles (15 % vs. 3 %; p &lt; 0.01). The rate of infection episodes in the ЕАСОРР-14 group was higher (50 % vs. 28 %) and in more cycles (15 % vs. 5 %; p &lt; 0.05). Due to the use of long-acting G-CSF (empegfilgrastim) the number of inpatient days could be reduced from 9 to 5.&#x0D; Conclusion. The results of this study demonstrate the advantage of long-acting G-CSF (empegfilgrastim) as compared with its discrete form (filgrastim) in intensified programs with a reduced inter-cycle interval and high risk of febrile neutropenia (EACODD-14 and EACOРР-14). The use of empegfilgrastim allowed to administer three times as many chemotherapy cycles adhering to the principle of dose intensity in a larger number of patients with advanced cHL stages.

Combination regimen of granulocyte colony-stimulating factor and recombinant human thrombopoietin improves the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells

Leukemia ranks as the one of most common causes of death from tumor. 51.4% of patients with leukemia are over 65 years old. However, the median overall survival (OS) of elderly leukemia patients is less than one year. It is urgent to explore more effective treatments for elderly patients with leukemia. Our recent prospective phase II single-arm study has revealed that combination regimen of granulocyte colony-stimulating factor (G-CSF) and recombinant human thrombopoietin (rhTPO) could improve the curative effect on elderly patients with leukemia, yet the precise mechanism remains unknown. This study demonstrated that combination of G-CSF and rhTPO showed greater effect on suppressing leukemia growth than G-CSF or rhTPO alone in vitro and in vivo. Mechanistically, G-CSF induced pyroptosis through ELANE in leukemia cells. Besides, rhTPO triggered ferroptosis by EP300 in leukemia cells. Moreover, rhTPO suppressed glutathione peroxidase 4 (GPX4) expression to induce ferroptosis through blocking the interaction between EP300 and GPX4 gene promoter via associating with EP300. In summary, this study illuminated that combination regimen of G-CSF and rhTPO improved the curative effect on elderly patients with leukemia through inducing pyroptosis and ferroptosis of leukemia cells. Therefore, our results provided a theoretical basis for combination regimen of G-CSF and rhTPO treating leukemia and potential therapeutic targets for leukemia.

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.

Comparison of the efficiency, safety, and survival outcomes in two stem cell mobilization regimens with cyclophosphamide plus G-CSF or G-CSF alone in multiple myeloma: a meta-analysis

Autologous stem cell transplantation as a frontline treatment for patients with multiple myeloma (MM) requires an adequate peripheral blood stem cell (PBSC) collection before processing. Granulocyte-colony stimulating factor (G-CSF) with or without cyclophosphamide (CTX) is a common regimen for PBSC mobilization; their benefits and risks are controversial. To compare the efficiency, safety, and survival outcomes between the two regimens, we conducted a meta-analysis including 18 studies with 4 prospective and 14 retrospective studies; a total of 2770 patients with MM were analyzed. The CTX plus G-CSF regimen had higher yields of total CD34+ cells (SMD = 0.39, 95% CI (0.30, 0.49)), and higher mobilization rates of the target ⩾ 2 × 106/kg (OR = 3.34, 95% CI (1.82, 6.11)) and 4 × 106/kg (OR = 2.16, 95% CI (1.69, 2.76)) cells. A favorable event-free survival (EFS) (HR = 0.73, 95% CI (0.58, 0.93), p = 0.01) and better 3-year EFS rate (OR = 1.65, 95% CI (1.1, 2.47), p = 0.02) were also reached in the patients with CTX plus G-CSF mobilization, although the risks of admission (OR = 26.49, 95% CI (7.31, 95.97)) and fever (OR = 13.66, 95% CI (6.21, 30.03)) during mobilization were increased, the treatment-related mortality was consistent (p = 0.26). The CTX plus G-CSF regimen was superior to the G-CSF-alone regimen for PBSC mobilization in patients with MM.

Stable colony-stimulating factor 1 fusion protein treatment increases hematopoietic stem cell pool and enhances their mobilisation in mice

BackgroundPrior chemotherapy and/or underlying morbidity commonly leads to poor mobilisation of hematopoietic stem cells (HSC) for transplantation in cancer patients. Increasing the number of available HSC prior to mobilisation is a potential strategy to overcome this deficiency. Resident bone marrow (BM) macrophages are essential for maintenance of niches that support HSC and enable engraftment in transplant recipients. Here we examined potential of donor treatment with modified recombinant colony-stimulating factor 1 (CSF1) to influence the HSC niche and expand the HSC pool for autologous transplantation.MethodsWe administered an acute treatment regimen of CSF1 Fc fusion protein (CSF1-Fc, daily injection for 4 consecutive days) to naive C57Bl/6 mice. Treatment impacts on macrophage and HSC number, HSC function and overall hematopoiesis were assessed at both the predicted peak drug action and during post-treatment recovery. A serial treatment strategy using CSF1-Fc followed by granulocyte colony-stimulating factor (G-CSF) was used to interrogate HSC mobilisation impacts. Outcomes were assessed by in situ imaging and ex vivo standard and imaging flow cytometry with functional validation by colony formation and competitive transplantation assay.ResultsCSF1-Fc treatment caused a transient expansion of monocyte-macrophage cells within BM and spleen at the expense of BM B lymphopoiesis and hematopoietic stem and progenitor cell (HSPC) homeostasis. During the recovery phase after cessation of CSF1-Fc treatment, normalisation of hematopoiesis was accompanied by an increase in the total available HSPC pool. Multiple approaches confirmed that CD48−CD150+ HSC do not express the CSF1 receptor, ruling out direct action of CSF1-Fc on these cells. In the spleen, increased HSC was associated with expression of the BM HSC niche macrophage marker CD169 in red pulp macrophages, suggesting elevated spleen engraftment with CD48−CD150+ HSC was secondary to CSF1-Fc macrophage impacts. Competitive transplant assays demonstrated that pre-treatment of donors with CSF1-Fc increased the number and reconstitution potential of HSPC in blood following a HSC mobilising regimen of G-CSF treatment.ConclusionThese results indicate that CSF1-Fc conditioning could represent a therapeutic strategy to overcome poor HSC mobilisation and subsequently improve HSC transplantation outcomes.

A novel treatment regimen of granulocyte colony-stimulating factor combined with ultra-low-dose decitabine and low-dose cytarabine in older patients with acute myeloid leukemia and myelodysplastic syndromes.

Background:Older patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) unfit for intensive chemotherapy are emergent for suitable treatment strategies. Hypomethylating agents and low-dose cytarabine have generated relevant benefits in the hematological malignancies over recent decades. We evaluated the efficacy and safety of the novel treatment regimen consisting of ultra-low-dose decitabine and low-dose cytarabine, with granulocyte colony-stimulating factor (G-CSF) in this population of patients.Methods and materials:Patients aged more than 60 years with newly diagnosed AML/MDS were enrolled to receive therapy combined of 300 µg subcutaneously per day for priming, decitabine 5.15–7.62 mg/m2/d intravenously and cytarabine 15 mg/m2/d twice a day subcutaneously and G-CSF for consecutive 10 days every 28 days. The study enrolled 28 patients unfit for standard intensive chemotherapy. The median age of patients was 68 years (range 60–83 years) and 20 (71.4%) patients harbored AML. The primary outcome was to evaluate overall response rate.Results:Overall, this novel ultra-low-dose treatment regimen was well tolerated, with 0% of both 4- and 8-week mortality occurrence. Objective response rate (CR + CRi + PR in AML and CR + mCR + PR in MDS) was 57.1% after the first treatment course. Responses of hematologic improvement (HI) aspect were achieved in 18 of 28 (64.3%) patients, 11 (39.3%), 12 (42.9%), and eight patients (28.6%) achieved HI-E, HI-P, HI-N, respectively.Conclusions:Untreated elderly with AML/MDS were well tolerated and benefited from this novel ultra-low-dose treatment regimen.

In memory of Academician A.I. Vorob'ev, Russian Academy of Medical Sciences and Russian Academy of Sciences Stability of Granulopoiesis Chronology under R(G)-DHAP Immuno-chemotherapy-Induced Cytotoxic Stress in Non-Hodgkin’s Lymphomas

Background. Chronology of granulopoiesis based on periodic hematopoiesis model has been thoroughly studied. However, the pattern of influence of immunotherapy-induced cytotoxic stress on the biological rhythm of a stem cell development requires further investigation. The interaction of antitumor drugs with normal hematopoietic cells is relevant for assessing the intensity of chemotherapy adverse events. Besides, there is a demand for studying hematopoiesis under cytotoxic stress to predict immunological reactivity as a condition for efficacy of immunotherapeutic agents, the effect of which is based on cell immunity. Aim. To study the chronological pattern of leukocyte count dynamics after R(G)-DHAP immunochemotherapy in non-Hodgkin’s lymphomas. Materials &amp; Methods. The dynamics of leukocyte count changes after R(G)-DHAP immunochemotherapy was analyzed using the data of 39 treatment courses in 19 non-Hodgkin’s lymphomas patients. After 18 out of 39 cycles of treatment granulocyte colony-stimulating factor (G-CSF) was administered to prevent granulocytopenia, in other cases the previously planned hematopoietic stem cell mobilization was performed according to the accepted protocol. Results. Time to activation of spontaneous granulopoiesis depends neither on G-CSF stimulation, nor on the total dose of growth-stimulating factor and corresponds on average to Day 10 or Day 11 of the break from the last day of immunochemotherapy. The tendency of shorter agranulocytosis duration on prophylactic use of G-CSF is associated with transient hyperleukocytosis at an early stage after completing immunochemotherapy. Regimens with platinum-based drugs, like R(G)-DHAP, are suggested to be combined with immunochemotherapeutic agents in patients with the failure of first-line chemotherapy. The time interval preceding myelopoiesis activation within the first days of the break between the courses is likely to contribute to the initiation of treatment with immunotherapeutic drugs after second-line chemotherapy. Conclusion. The determination of granulopoiesis dynamics under R(G)-DHAP immunochemotherapy-induced cytotoxic stress enables to plan the optimum G-CSF regimen and to predict the optimum timing of immune antitumor effect combined with chemotherapy.

Haploidentical stem cell transplantation for aplastic anemia: the current advances and future challenges.

Haematopoietic stem cell transplantation (HSCT) is a curative option for severe aplastic anemia (SAA). Finding a suitable matched donor in a timely manner is a challenge. The availability of haploidentical donors and their successful use in transplantation have expanded valid choices for SAA. In recent decades, haploidentical HSCT (haplo-HSCT) for the treatment of SAA has been continuously attempted, and great strides have been made. Nowadays, haplo-HSCT using different regimens has overcome the difficulty of graft failure and severe graft-versus-host disease (GvHD), and achieved inspiring survival outcomes in SAA. The regimens consist mainly of granulocyte colony-stimulating factor (G-CSF) plus antithymocyte globulin (ATG), posttransplantation cyclophosphamide (PT-Cy), and ex vivo graft T-cell depletion (TCD). In particular, the G-CSF and ATG-based regimen includes the largest sample size and the successful wide use of the G-CSF and ATG-based regimen has promoted haplo-HSCT a higher priority in SAA patients without matched related or unrelated donors in China. Recent studies have also indicated that haplo-HSCT using PT-Cy or TCD regimen is a practicable alternative, but the sample size is relatively small. Here, we offer an overview of clinical results obtained through the use of haploidentical transplantation in SAA, mainly focusing on current advances and future challenges.

Mgta-145, in Combination with Plerixafor in a Phase 1 Clinical Trial, Mobilizes Large Numbers of Human Hematopoietic Stem Cells and a Graft with Immunosuppressive Effects for Allogeneic Transplant

Background . The majority of hematopoietic stem cell (HSC) transplants are performed using peripheral blood mobilized with granulocyte-colony stimulating factor (G-CSF) given over 5 days. The goal of a successful transplant is to reliably mobilize optimal numbers of HSCs necessary for rapid and consistent multilineage engraftment. Infusion of mobilized allogeneic grafts results in significant acute and chronic graft-versus-host disease (GvHD) in up to 80% of allogeneic transplant recipients. A reliable and rapid method to mobilize HSC-rich grafts with reduced GvHD potential would be clinically meaningful. In a Phase 1 study of normal volunteers, MGTA-145 (GroβT), a CXCR2 agonist, when combined with plerixafor, a CXCR4 inhibitor, robustly and rapidly mobilized sufficient HSCs for a safe transplant after only a single day of dosing and apheresis/collection. Here, we phenotypically and functionally profile these mobilized grafts obtained from human volunteers and show that MGTA-145 + plerixafor mobilizes grafts with &amp;gt;10-fold higher engraftment potential (as measured by SCID-repopulating units in NSG mice), a marked reduction in xenogeneic GvHD, and enhanced overall survival compared to G-CSF or plerixafor alone grafts. Results . In healthy donors, a peak of 40 CD34+ cells/μL were mobilized with MGTA-145 + plerixafor (n=12 donors). 11 of 12 (92%) of these donors mobilized &amp;gt;20 CD34+ cells/μL with single day dosing compared to only 8 of 14 (57%) achieving the same CD34+ cell target treated with plerixafor alone. Eight donors were mobilized with a single dose of MGTA-145 + plerixafor and apheresed on the same day. A median of 4x106 (1.5-7.0x106) CD34+ cells/kg were obtained (n=8 donors) from a median 20 (13-20) L collection. 35.8 (18.5-40.9)% of these cells were CD90+CD45RA-, a CD34+ subset enriched for HSCs, compared to only 6.9 (5.3-9.0)% with G-CSF (p&amp;lt;0.001, n=3 donors). Mechanistically, MGTA-145 bound to CXCR2 on neutrophils and led to a modest and transient increase in plasma concentrations of matrix metalloproteinase 9 (MMP- 9), a downstream target on neutrophils. To assess engraftment, we transplanted mobilized peripheral blood cells from healthy donors after a 5-day regimen of G-CSF or a single dose of plerixafor alone or MGTA-145 + plerixafor at limit dilution into sublethally irradiated primary and secondary NSG mouse recipients (n=3 cell doses, n=7-8 mice/group). Multilineage human engraftment was measured by flow cytometry 16 weeks post-transplant and SCID-repopulating cell (SRC) number was calculated (Figure 1A). MGTA-145 + plerixafor mobilized grafts (n=4 donors) led to a 23-fold increase in engraftment compared to G-CSF mobilized grafts (p&amp;lt;0.001, n=3 donors) and 11-fold higher engraftment compared to plerixafor mobilized grafts (p&amp;lt;0.001, n=3 donors). Immune cell subsets (B, T, and NK cells and cell subsets) mobilized by MGTA-145 + plerixafor were similar to those mobilized by plerixafor alone. While CD3+ T-cell numbers were comparable between MGTA-145 + plerixafor and plerixafor alone, MGTA-145 + plerixafor mobilized 0.2 (0.0-0.6) x108/kg CD8+ T-cells, constituting 1.8 (0.5-4.8)% of the graft, a number and proportion significantly lower than that mobilized by either G-CSF or plerixafor alone. To determine the effect of the mobilization regimen on xenogeneic GvHD, we developed a xenograft GvHD model in NSG mice where 6x106 PBMCs from various graft sources were infused into sublethally-irradiated animals (n=3-6 donors per graft source). Notably, MGTA-145 + plerixafor mobilized grafts resulted in significantly less GvHD than G-CSF (p&amp;lt;0.01) or plerixafor (p&amp;lt;0.001) grafts (Figure 1B). In vivo cellular subset depletion studies suggested that the GvHD protective effect in MGTA-145 + plerixafor grafts may be in part due to immunosuppressive monocytes which were not present, or present to a lesser degree, in grafts from donors mobilized with G-CSF or plerixafor. Conclusions . These data demonstrate that MGTA-145 + plerixafor is a rapid, reliable, and G-CSF free method to obtain high numbers of HSCs with durable engraftment potential and a graft with highly immunosuppressive properties. These data suggest that MGTA-145 + plerixafor is an effective single-day mobilization/collection regimen for both autologous and allogeneic stem cell transplantation resulting in enhanced engraftment and reduced GvHD in this xenograft model. Disclosures Goncalves: Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company, Patents &amp; Royalties. Hyzy:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Hammond:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Falahee:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Howell:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Pinkas:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Schmelmer:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Hoggatt:Magenta Therapeutics: Consultancy, Current equity holder in publicly-traded company. Scadden:Magenta Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Devine:Magenta Therapeutics: Consultancy. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees. Savage:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company. Davis:Magenta Therapeutics: Current Employment, Current equity holder in publicly-traded company.

Impact of granulocyte colony-stimulating factor on FOLFIRINOX-induced neutropenia prevention: A population pharmacokinetic/pharmacodynamic approach.

Granulocyte colony-stimulating factor (G-CSF) is frequently prescribed to prevent chemotherapy-induced neutropenia, but the administration schedule remains empirical in case of bimonthly chemotherapy such as FOLFIRINOX regimen. This pharmacokinetic/pharmacodynamic (PK/PD) study was performed to determine the effect of different G-CSF regimens on the incidence and duration of neutropenia following FOLFIRINOX administration in order to propose an optimal G-CSF dosing schedule. A population PK/PD model was developed to describe individual neutrophil time course from absolute neutrophil counts (ANC) obtained in 40 advanced cancer patients receiving FOLFIRINOX regimen. The structural model considered ANC dynamics, neutropenic effect of cytotoxics and the stimulating effect of G-CSF on neutrophils. Final model estimates were used to simulate different G-CSF dosing schedules for 1000 virtual subjects. The incidence and duration of neutropenia were then calculated for different G-CSF dosing schedules. The final model successfully described the myelosuppressive effect induced by the 3 cytotoxics for all patients. Simulations showed that pegfilgrastim administration reduced the risk of severe neutropenia by 22.9% for subjects with low ANC at the start of chemotherapy. Median duration in this group was also shortened by 3.1 days when compared to absence of G-CSF. Delayed G-CSF administration was responsible for higher incidence and longer duration of neutropenia compared to absence of administration. The PK/PD model well described our population's ANC data. Simulations showed that pegylated-G-CSF administration 24 hours after the end of chemotherapy seems to be the optimal schedule to reduce FOLFIRINOX-induced neutropenia. We also underline the potential negative effect of G-CSF maladministration.

A Novel Hematopoietic Progenitor Cell Mobilization Regimen Comprising Bortezomib, G-CSF, and Preemptive Plerixafor for Multiple Myeloma.

Adequate hematopoietic progenitor cell collection is critical for autologous peripheral blood stem cell transplantation. Conventionally, patients with multiple myeloma are treated with high-dose cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) or G-CSF alone to mobilize their peripheral blood stem cells. However, some patients exhibit insufficient stem cell recruitment in response to these regimens. Recently, plerixafor has been approved for coverage by insurance in Japan. Combination treatment with plerixafor and G-CSF is now a standard procedure. In addition, treatment with bortezomib and G-CSF results in efficient stem cell recruitment. On the basis of the results from mouse studies, we hypothesized that combination treatment with bortezomib ensures efficient mobilization and mediates in vivo purging of malignant cells. Therefore, we administered a regimen of bortezomib, G-CSF, and preemptive plerixafor to 10 patients with multiple myeloma, and analyzed its efficacy and safety. The median patient age was 68 years. We collected CD34-positive cells (median: 4.9×106/kg) in a single session of apheresis from all patients. We observed no obvious myeloma cell contamination in the collected product or serious toxicity during treatment and collection. After collection, we performed autologous peripheral blood stem cell transplantation and confirmed engraftment in all patients (median: day 10). We found that the regimen is safe and reliably facilitated the collection of sufficient autologous peripheral blood stem cells by apheresis from all patients in a single day. Despite the small patient group size, we conclude that the regimen is promising for safe and efficient collection of peripheral blood stem cells for autologous transplantation in patients with multiple myeloma.

Viagra Enables Efficient, Single-Day Hematopoietic Stem Cell Mobilization.

SummaryHematopoietic stem cell (HSC) transplantation is a curative treatment for a variety of blood and immune disorders. Currently available methods to obtain donor HSCs are suboptimal, and the limited supply of donor HSCs hampers the success and availability of HSC transplantation therapies. We recently showed that manipulation of vascular integrity can be employed to induce HSC mobilization from the bone marrow to the blood stream, facilitating non-invasive collection of HSCs. Here, we tested whether FDA-approved vasodilators are capable of mobilizing HSCs. We found that a rapid, 2-h regimen of a single oral dose of Viagra (sildenafil citrate) combined with a single injection of the CXCR4 antagonist AMD3100 leads to efficient HSC mobilization at levels rivaling the standard-of-care 5-day regimen of granulocyte-colony stimulating factor (G-CSF/Filgrastim/Neupogen). Our findings solidify vascular integrity as an essential regulator of HSC trafficking and provide an attractive, single-day regimen for HSC mobilization using already FDA-approved drugs.

3174 – TANDEM MYELOID GROWTH FACTOR TREATMENT ENHANCED THE TOTAL HAEMATOPOIETIC STEM CELL (HSC) POOL AND MAGNITUDE OF HSC MOBILISATION

Autologous HSC transplant is a common therapeutic strategy for some haematological malignancies but is unachievable in up to 40% of cases due to insufficient mobilisation of HSCs for successful transplantation. The monocyte-macrophage colony stimulating factor-1 (CSF1) improves HSC transplantation outcomes in preclinical models and clinical trials, but the underlying mechanism of CSF1 induced benefit is unclear. BM macrophages are a key component of the HSC niches and a primary target of granulocyte colony-stimulating factor (G-CSF) induced HSC mobilisation. We examined CSF1 impacts on HSC frequency using a modified CSF1-Fc molecule that has improved drug qualities. Haematopoietic progenitor cells (HPC), but not HSCs or multipotent progenitors (MPP), expressed the CSF1 receptor. Acute CSF1-Fc treatment (4 x daily injection) induced a robust myeloproliferative response that was evident 1 week post the initial injection. At this time, BM HSCs (17 fold) and MPP (19 fold), but not HPC, were significantly reduced. However, at 2 weeks post the first CSF1-Fc injection, after the myeloproliferative event had resolved, the overall pool of HSCs in BM (1.6 fold), and unexpectedly spleen (9.2 fold), was significantly elevated compared to controls. A mobilising regimen of G-CSF started at 2 weeks post CSF1-Fc treatment enhanced HSC mobilisation (2.5 fold) into blood when compared to mice treated with G-CSF only. This increase in mobilised HSCs was verified via competitive secondary transplantation. The data suggest that CSF1 has complex indirect effects on HSCs to increase HSC frequency and promote formation of extramedullary HSC niches. CSF1-induced increased in the total HSC pool may contribute to the reported improvement in transplantation outcomes associated with CSF1 therapy and reveals a novel strategy to increase HSCs prior to mobilisation.

Efficacy and toxicity of cladribine for the treatment of refractory acute myeloid leukemia: a meta-analysis.

Purpose: To investigate the overall efficacy and toxicity of cladribine and cladribine-based chemotherapy in the treatment of patients with refractory acute myeloid leukemia (AML) based on meta-analysis.Methods: PubMed, EMBASE database, and the Cochrane Library were searched for relevant studies. Eligible studies were clinical trials of refractory AML assigned to cladribine with data on efficacy including complete remission (CR) rate, overall response rate (ORR) and overall survival. Toxicity was evaluated based on the early death rate and the incidence of grade 3 and 4 adverse events (AEs).Results: A total of 10 clinical trials including 422 refractory AML patients were analyzed. The overall CR rate was 42.2% (95% CI: 31.0–54.3%). And the ORR of seven trials including 235 patients was 49.7% (95% CI: 33.5–66.0%). The overall early death rate of 260 patients enrolled in five trials was 6.8% (95% CI: 4.3–10.6%). Thrombocytopenia, anemia, neutropenia, and infection were the most common grade 3 and 4 AEs.Conclusion: Cladribine is effective for refractory AML, and its efficacy can be increased with the combination of cladribine, cytarabine, and granulocyte-colony stimulating factor regimen.

Mgta-145 in Combination with Plerixafor Mobilizes Large Numbers of Hematopoietic Stem Cells That Lead to Rapid Engraftment Following Autologous Transplantation in Nonhuman Primates

The majority of bone marrow transplants (BMT) utilize granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood (mPB) as the source of hematopoietic stem cells (HSCs). However, CD34+ harvest with G-CSF is variable and frequently unpredictable, often requires multiple apheresis sessions and is associated with significant side effects. Identification of a mobilizing regimen that consistently produces high numbers of engraftable CD34+ cells without the need for G-CSF would be ideal. We previously reported that MGTA-145, a CXCR2 agonist, when combined with the CXCR4 inhibitor, plerixafor, rapidly mobilizes CD34+ cells (Blood 2017 130:1920). In the current study, we evaluated the ability of MGTA-145 plus plerixafor to mobilize and effectively engraft HSCs in a pre-clinical nonhuman primate (NHP) stem cell transplantation animal model. Rhesus macaques were mobilized with a single dose of MGTA-145, plerixafor or MGTA-145 plus plerixafor versus a multi-dose regimen of G-CSF. Detailed immune profiling was performed at 0 through 24 hours post treatment. Within 4 hours of dosing, MGTA-145 plus plerixafor resulted in a 16-fold increase in the number of CD34+CD90+CD45RA- HSCs in the periphery (p=0.0003, n=11), which were previously shown to predict successful transplant as evidenced by rapid neutrophil and platelet recovery in an autologous NHP transplant model (Sci Trans Med 2017 9:1145). Next, NHPs mobilized with MGTA-145 plus plerixafor were leukapheresed and CD34+ cells enriched by positive selection. These cells were genetically modified and transplanted back into the same NHP conditioned with 1080 cGy (4 doses over 48 hours). A representative apheresis yield was 2.3 × 106 CD34+ and 0.9 × 106 HSCs per kg, and the final dose of gene-marked CD34+ and HSCs for transplant following 48 hours in culture was 1.7 × 106 and 0.8 × 106 per kg, respectively. GFP marking in vivo was consistent with the marking on the primitive HSCs prior to transplant. Neutrophil and platelet engraftment occurred at day 10 and 15 post-transplant, respectively (Figure 1). The study is ongoing, and additional follow-up data on all available animals will be presented. Co-administration of MGTA-145 plus plerixafor leads to both rapid and efficacious mobilization of CD34+ cells in the pre-clinical NHP large animal model. We found that MGTA-145 plus plerixafor mobilized grafts contain large numbers of CD34+CD90+CD45RA- HSCs, which are capable of long-term multilineage reconstitution, and preliminary results from autologous transplantation studies in NHPs demonstrate that MGTA-145 plus plerixafor mobilized HSCs lead to rapid neutrophil and platelet recovery. This study demonstrates, for the first time, that CD34+ cells mobilized with a novel regimen of MGTA-145 plus plerixafor can be collected via leukapheresis, subsequently gene modified and transplanted into NHPs, resulting in rapid engraftment.

Co-Administration of Mgta-145 and Plerixafor Rapidly Mobilizes High Numbers of Hematopoietic Stem Cells and Graft-Versus-Host Disease Inhibiting Monocytic Cells in Non-Human Primates

The majority of bone marrow transplants (BMTs) utilize granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood (mPB) as the source of hematopoietic stem cells (HSCs). Mobilization with G-CSF requires a multi-day dosing regimen and fails to mobilize a large proportion of CD34+CD90+CD45RA- HSCs, the cell type responsible for hematopoietic engraftment. Moreover, up to 80% of allogenic recipients will experience significant side effects such as acute graft-versus-host disease (GvHD), even though G-CSF mPB contains a small and variable number of immunosuppressive monocytes (Vendramin et al., BBMT 2014). Identification of a mobilizing regimen that consistently and rapidly produces high numbers of HSCs and immunosuppressive monocytes without the need for G-CSF would be ideal. We previously reported that MGTA-145, a CXCR2 agonist, rapidly mobilizes HSCs when combined with the CXCR4 inhibitor, plerixafor (Blood 2017 130:1920). In the present study, detailed profiling was performed at 0 through 24 hours after mobilization of non-human primates (NHPs) with a single dose of MGTA-145, plerixafor, or MGTA-145 plus plerixafor versus a multi-dose, five-day regimen of G-CSF. MGTA-145 plus plerixafor led to a 19-fold increase in number of CD34+CD90+CD45RA- HSCs within four hours of dosing (p As the risk of GvHD remains a significant clinical problem in the allogenic setting, MGTA-145 plus plerixafor may rapidly mobilize an advantageous graft relative to the standard of care, G-CSF, since MGTA-145 plus plerixafor results in significantly higher numbers of both engraftable HSCs and highly immunosuppressive monocytes.

MGTA-145 in Combination with Plerixafor Rapidly Mobilizes High Numbers of Hematopoietic Stem Cells and Graft-Versus-Host Disease Inhibiting Myeloid-Derived Suppressor Cells in Non-Human Primates

Background. The majority of bone marrow transplants (BMTs) are performed with granulocyte-colony stimulating factor (G-CSF) mobilized peripheral blood (mPB) as the source of hematopoietic stem cells (HSCs) for patients. Up to 80% of mPB allogeneic recipients, however, will experience graft-versus-host disease (GvHD). Despite higher levels of CD3+ T cells in mPB grafts compared to BM, the level of acute GvHD observed following transplant of HLA-matched mPB is comparable to HLA-matched BM. One explanation is that G-CSF mobilized grafts contain myeloid-derived suppressor cells (MDSCs) possessing potent immunosuppressive properties capable of inhibiting T cell proliferation in vitro. The percentage of MDSCs is variable in grafts mobilized with G-CSF and clinical data suggest that patients transplanted with mPB grafts that contain higher numbers of MDSCs may have better outcomes including lower rates of acute GvHD (Vendramin et al., BBMT 2014). Identification of a mobilizing regimen that consistently produces high numbers of HSCs and MDSCs may be preferred.We recently reported that MGTA-145 (GroβT), a CXCR2 agonist, when combined with the CXCR4 inhibitor, plerixafor, robustly mobilizes HSCs (Blood 2017 130:1920). In this study, non-human primates (NHPs) were mobilized with a single dose of MGTA-145, plerixafor, or MGTA-145/plerixafor versus a multi-dose regimen of G-CSF, and mPB was harvested to allow detailed immune profiling at 0 through 24 hours. We observed a significant and rapid increase in number of HSCs and CD34dim monocytes with potent in vitro and in vivo immunosuppressive properties.Results. MGTA-145/plerixafor consistently produced a 16-fold increase in number of CD34+CD90+CD45RA- HSCs within four hours of dosing (p=0.0003, n=11). Profiling of graft subsets from these primates also showed a 10-fold increase over baseline in the number of CD34dim monocytes at 4 hours post treatment (p<0.0001, n=11, Figure 1A) that corresponded to 2-3-fold higher frequency and number compared to G-CSF or plerixafor alone (p<0.01, n=2-5) and correlated with degree of HSC mobilization (p<0.0001). To determine if this monocytic cell population had immunosuppressive properties, CD34dim cells were sorted from peripheral blood of NHPs treated with MGTA-145/plerixafor and co-cultured with anti-CD2, anti-CD3 and anti-CD28-stimulated autologous T cells. MGTA-145/plerixafor CD34dim monocytes suppressed T cell proliferation, as measured by CFSE staining after four days.To assess whether these immunosuppressive monocytes may prevent GvHD, we developed a xenograft GvHD model in NSG mice. MGTA-145/plerixafor mPB (6 x 106 PBMCs) containing a high percentage of CD34dim monocytes were injected into sublethally irradiated NSG mice. This was compared to unmobilized primate PBMCs (6 x 106 PBMCs) containing relatively low numbers of CD34dim cells. At day 20, all mice (8/8) transplanted with unmobilized PBMCs had died of acute GvHD compared to none of the mice transplanted with MGTA-145/plerixafor mPB. Mice transplanted with unmobilized PBMCs also demonstrated 3-fold higher numbers of T-cells and increased T-cell activation compared to mice transplanted with MGTA-145/plerixafor mobilized PBMCs (p<0.01, n=6-8). At day 60 post-transplant, 7/8 mice remained alive (Figure 1B, p<0.0001). To assess whether this immunosuppressive effect is due to CD34dim monocytes, we sorted these cells and transplanted PBMCs depleted of CD34dim monocytes into NSG mice. In addition, experiments comparing the number and function of primate HSCs mobilized by MGTA-145/plerixafor or G-CSF alone using the NSG engraftment model and using autologous NHP transplant coupled with ex vivo HSC gene therapy are ongoing.Conclusions. Co-administration of MGTA-145/plerixafor in NHPs results in both rapid and efficacious mobilization of highly enriched HSCs and a CD34dim monocyte population with potent immunosuppressive activity compared to cells mobilized with plerixafor alone or with the current standard of care, G-CSF. The increased number of these immunosuppressive monocytes compared to G-CSF has the potential to reduce GvHD in the allogenic transplant setting. Thus, MGTA-145/plerixafor may offer an advantageous graft in the allogeneic setting where the risk of GvHD remains a significant clinical problem. IND-enabling studies of MGTA-145 are in progress to assess this regimen for mPB collection and transplant. [Display omitted] DisclosuresGoncalves:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Falahee:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. Li:Magenta Therapeutics: Employment, Equity Ownership. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Morrow:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.

A phase IV, randomized, multicenter, open-label trial comparing efficacy and systemic exposure for a standard weight-based dose versus a fixed dose of plerixafor in combination with G-CSF in patients with Non-Hodgkin\u2019s lymphoma weighing \u226470\u2009kg

A randomized, multicenter, open-label study explored the effect of a fixed-dose (FD) of plerixafor versus the approved weight-based (WB) dose for the mobilization of hematopoietic stem cells (HSCs) in patients with non-Hodgkin’s lymphoma and a body weight of ≤70 kg. After mobilization with granulocyte colony-stimulating factor (G-CSF) 10 μg/kg/day for 4 days, patients were randomized 1:1 to either plerixafor FD 20 mg (n = 30) or WB 0.24 mg/kg (n = 31) on the evening of Day 4. Co-primary endpoints were the proportion of patients achieving ≥5 × 106 CD34+ cells/kg in ≤4 days of apheresis, and total systemic exposure to plerixafor (area under the concentration–time curve from 0 to 10 h [AUC0–10]). There was no statistically significant difference between the proportion of patients attaining the primary efficacy endpoint (60% FD arm, 55% WB arm; P = 0.395). Exposure to plerixafor was greater in the FD arm relative to the WB arm; however, there was no appreciable difference regarding fold increases of peripheral blood CD34+ cells. The safety profile was similar between treatment groups. These results suggest there is no statistically significant difference in HSC mobilization with a standard WB dosing regimen of plerixafor plus G-CSF in patients with low body weight compared with an FD regimen.