scholarly journals Clonal Analysis of Human Bone Marrow CD34+ Cells Edited By BCL11A-Targeting Zinc Finger Nucleases Reveals Clinically Relevant Levels of Fetal Globin Expression in Edited Erythroid Progeny

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3234-3234 ◽  
Author(s):  
Kai-Hsin Chang ◽  
Timothy Sullivan ◽  
Mei Liu ◽  
Xiao Yang ◽  
Chao Sun ◽  
...  

Abstract Sickle cell disease (SCD) is one of the most common inherited blood disorders and is caused by a mutation at the adult beta globin gene resulting in substitution of valine for glutamic acid at position 6 in the encoded protein. While SCD can be cured by hematopoietic stem cell transplant (HSCT), complete donor chimerism is not required to achieve clinical benefits. Stable mixed chimerism of 10-15% in bone marrow or peripheral blood nucleated cells with >70% donor-derived RBCs has been reported to achieve transfusion independence and a symptom-free state in a SCD patient. It has also been proposed that SCD can be treated by reactivating developmentally silenced fetal gamma globin to form fetal hemoglobin (alpha2gamma2, HbF), which inhibits polymerization of HbS. The effect of HbF is predicted to be maximal when HbF content per cell exceeds 10 pg (~30% of total Hb). Furthermore, pathology is prevented when protective F cells (>30% HbF per cell) constitute >70% of total RBCs. We hypothesize that in a gene therapy setting, if >15% of SCD patients' autologous HSCs are programmed to produce protective F cells during erythropoiesis, it will translate into >70% protective F cells in circulation and provide significant alleviation of clinical symptoms. Genome wide association studies have identified BCL11A as a major modifier of HbF levels. Subsequent studies have shown that BCL11A plays a critical role in the fetal to adult globin developmental switch and in repressing fetal globin expression in adult erythroid cells. Conditional inactivation of BCL11A in adult erythroid cells leads to high levels of pan-cellular fetal globin expression and correction of hematologic and pathologic defects in a humanized SCD mouse model. Previously, we have reported that zinc finger nucleases (ZFNs) targeting BCL11A either in the coding region or the GATAA motif in the erythroid-specific enhancer efficiently disrupt the BCL11A locus in human primary CD34+ cells following electroporation of ZFN-encoding mRNA. Elevated fetal globin expression in bulk erythroid cultures was observed following disruption. To determine what percentage of HSPCs have been modified and whether the HbF/F cell content has reached the hypothesized therapeutic level, we analyzed erythroid cells clonally derived from ZFN-transfected CD34+ cells. Genotype of each clonal culture was determined by deep sequencing and globin production was analyzed by a highly sensitive UPLC method. We found that up to 80% of the BFU-Es had both BCL11A alleles edited, half of which had KO/KO alleles (either out of frame mutations for coding region or elimination of the GATAA motif in the enhancer). BCL11A coding KO/KO cells expressed on average 79.1% ± 12.2% fetal globin (Mean ± SD) whereas GATAA motif enhancer region KO/KO cells expressed approximately 48.4% ± 14.1% fetal globin, in comparison with 14.5% ± 9.6% in WT/WT cells . These levels of fetal globin should be sufficiently high to confer protection against HbS polymerization in sickle cells. WT/KO cells in both coding and enhancer editing experiments showed an intermediate phenotype with fetal globin averaging 26.9%± 9.9% and 25.79% ± 12.6%, respectively. Interestingly, when background (WT/WT) fetal globin level was subtracted, the fetal globin levels in WT/KO cells are comparable to those observed in patients with BCL11A haploinsufficiency, which average 14.6%± 10.3%. Together, our data demonstrate that genome editing of BCL11A using highly efficient ZFNs can lead to clinically relevant levels of fetal globin expression in KO/KO erythroid cells. If the frequency of KO/KO BFU-Es we observed in vitro reflects the frequency of KO/KO HSCs in bone marrow after autologous transplantation, genome editing of BCL11A has the potential to provide significant clinical benefit for patients with SCD. Disclosures Chang: Biogen: Employment, Equity Ownership. Sullivan:Biogen: Employment, Equity Ownership. Liu:Biogen: Employment, Equity Ownership. Yang:Biogen: Employment, Equity Ownership. Sun:Biogen: Employment, Equity Ownership. Vieira:Biogen: Employment, Equity Ownership. Zhang:Biogen: Employment. Hong:Biogen: Employment, Equity Ownership. Chen:Biogen: Employment, Equity Ownership. Smith:Biogen: Employment, Equity Ownership. Tan:Biogen: Employment, Equity Ownership. Reik:Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Urnov:Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Rebar:Sangamo BioSciences: Employment. Danos:Biogen: Employment, Equity Ownership. Jiang:Biogen: Employment, Equity Ownership.

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 203-203 ◽  
Author(s):  
Siyuan Tan ◽  
Kai-Hsin Chang ◽  
Sarah Smith ◽  
Kai Chen ◽  
Timonthy Sullivan ◽  
...  

Abstract Ablation of Bcl11A could be a viable approach for the treatment of β-hemoglobinopathies such as β-thalassemia and sickle cell disease (SCD), since patients with Bcl11A haploinsufficiency have persistently high levels of fetal hemoglobin (HbF) (up to 30%), which are associated with development of minimal to no disease symptoms. Genome editing by engineered zinc-finger nucleases that target either the exon 2 (exon ZFN) or the GATA motif of the erythroid specific enhancer (enhancer ZFN) of Bcl11A has been shown to increase HbF level in erythroid progeny from mobilized peripheral hematopoietic stem and progenitor cells (PB-CD34+ HSPCs). However, peripheral mobilization of CD34+ cells is associated with high risk and currently is not an option for SCD patients. Therefore, we investigated the efficacy of genome editing of Bcl11A in bone marrow derived CD34+ cells (BM-CD34+ HSPCs). We first established a clinically compatible large-scale process to isolate CD34+ HSPCs from human bone marrow aspirates and to transiently express the ZFN protein by mRNA electroporation. The CD34+ isolation process resulted in ~ 95% pure CD34+ cells with greater than 90% viability. Both the exon and the enhancer ZFN drove 50-60% Bcl11A gene editing, resulting in a robust elevation of HbF in the erythroid progeny. Notably, the BM-CD34+ HSPCs were found to contain a small population (10 to 25%) of CD34+CD19+ pro-B cells that were refractory to ZFN transfection under our current electroporation condition. Since CD34+CD19+ pro-B cells are not expected to contribute to reconstituting the hematopoietic system other than B-cell lineage, the Bcl11A editing efficiency in the multipotent BM-CD34+ HSPC could be even higher. The engraftment abilities of Bcl11A edited BM-CD34+ cells were then investigated in an immunodeficient NOD/scid/gamma (NSG) mouse model. At a dose of 1 million cells per mouse, treatment with either the exon ZFN or the enhancer ZFN did not detectably impact engraftment or multi-lineage reconstitution compared with untreated cells. However, Bcl11A marking in engrafted human cells was found to be markedly higher in the mice treated by the enhancer ZFN than that by the exon ZFN. The exon ZFN resulted in a strong bias towards in-frame mutations across multi-lineages with the strongest effect observed in the B-cell lineage, suggesting that a threshold level of Bcl11A is required for efficient hematopoietic reconstitution and that cells fully lacking it due to disruption of the coding sequence are at a disadvantage. In contrast, the enhancer ZFN resulted in comparable Bcl11A marking across all lineages with no apparent selection for cells with a functional GATA sequence. Collectively, these data indicate that genome editing of the erythroid specific enhancer of Bcl11A in BM-CD34+ promotes HbF reactivation in the erythroid progeny while maintaining the engraftment and multi-lineage repopulating activities of edited BM-CD34+ HSPCs, which supports further clinical development of this approach for the treatment of SCD. Disclosures Tan: Biogen: Employment, Equity Ownership. Chang:Biogen: Employment, Equity Ownership. Smith:Biogen: Employment, Equity Ownership. Chen:Biogen: Employment, Equity Ownership. Sullivan:Biogen: Employment, Equity Ownership. Zhou:Biogen: Employment, Equity Ownership. Reik:Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Urnov:Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Rebar:Sangamo BioSciences: Employment. Danos:Biogen: Employment, Equity Ownership. Jiang:Biogen: Employment, Equity Ownership.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4844-4844
Author(s):  
Blake Warbington ◽  
Daniel Weinstein ◽  
David Mallinson ◽  
Daria Olijnyk ◽  
Sarah Paterson ◽  
...  

Abstract Background AMR-001, an autologous CD34+ cell product derived from mini-marrow harvest, is currently undergoing Phase II trials to treat acute myocardial infarction (AMI). AMR-001 is administered to the patient by infusion via the infarct related artery within five to ten days following coronary artery stenting post AMI. At the time of infusion, it is believed that the infarct-region SDF-1 (stromal derived factor) levels are peaked and scar formation has not yet occurred. It was found that, in addition to the quantity of CD34+ cells infused, improvement in cardiac perfusion and infarct size correlated with the mobility potential of CD34+ cells mediated by a SDF-1 gradient (Quyyumi et al, Am Heart J 2011, 161:98–105). We have developed a cell based in vitro mobility assay as a potential potency release assay for AMR-001. However, this assay is not suitable for a Phase III or commercial scale release assay due to the length of the assay, high skill level required to perform, and variability. To develop a more robust assay, we have initiated a study to identify potential microRNAs (miRNAs) that may be used as biomarkers for CD34+ cell SDF-1 driven migration. Our preliminary results suggest CD34+ cells with different mobility potentials may be characterized by miRNA fingerprinting. Methods Cryopreserved purified CD34+ cells derived from bone marrow of healthy donors were purchased from a commercial vendor. Thawed CD34+ cells were washed and the cells were assayed in an in vitro transwell system (Jo et al, J Clin Invest 2000, 105:101-111). The trans-membrane migration of CD34+ cells into the lower chamber in the presence of SDF-1, as well as the non-mobilized CD34+ cells in the upper chamber, were collected after 4 hours incubation at 37°C. Total RNA of the cells was isolated and the miRNA expression profile was analyzed using SurePrint G3 Human v16 microRNA 8x60K microarray slide (Agilent, Santa Clara, CA). A normalization algorithm was used to generate miRNA expression profiles (SistemQC™, Sistemic, Ltd) for the characterization of untreated cells, the mobilized population that migrate towards SDF-1, and non-mobilized population; from two independent donors. Results Two hundred and four (204) miRNAs were reliably detected across the cell samples. The mobilized cells had different miRNA profiles compared with non-mobilized/untreated cells. Hierarchical cluster analysis showed that mobilized cells grouped separately from the non-mobilized/untreated cells. Conclusion Analysis of the miRNA profiles of the CD34+ cells across two independent donors, identified a number of key miRNAs (kmiRs™) that represent possible markers for a mobility phenotype. Additional samples will be analyzed to confirm these preliminary findings. This approach will enable the identification of markers associated with mobility potential of CD34+ cells and the potential development of a molecular biomarker assay for potency. Disclosures: Warbington: Progenitor Cell Therapy, LLC: Employment. Weinstein:Progenitor Cell Therapy, LLC: Employment. Mallinson:Sistemic, Ltd.: Employment, Equity Ownership. Olijnyk:Sistemic, Ltd.: Employment. Paterson:Sistemic, Ltd.: Employment. Ridha:Sistemic, Ltd.: Employment. O'Brien:Sistemic, Ltd.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Lin:Progenitor Cell Therapy, LLC: Employment. LeBlon:Progenitor Cell Therapy, LLC: Employment. Fong:NeoStem, Inc.: Employment. Chan:Progenitor Cell Therapy, LLC: Employment.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 204-204 ◽  
Author(s):  
Fyodor D Urnov ◽  
Andreas Reik ◽  
Jeff Vierstra ◽  
Kai-Hsin Chang ◽  
Yuanyue Zhou ◽  
...  

Abstract We describe here a fundamentally novel way to develop a disease therapeutic: combining genome-wide association studies (GWAS) with targeted genome editing to create, in a clinically compliant setting, a disease-ameliorating genotype in the patient's own cells. In β-thalassemia, elevated levels of fetal hemoglobin (HbF) lessen or eliminate disease symptoms, thus making a reversal of HbF silencing in patients an appealing therapeutic strategy. Loss-of-function variants in the erythroid-specific enhancer of the fetal globin repressor, BCL11A, elevate HbF; rare individuals carrying a monoallelic knockout of BCL11A exhibit no known hematologic abnormality and up to 30% circulating HbF. We previously reported de novo knockout of BCL11A using targeted genome editing with engineered zinc finger nucleases (ZFNs) yielding up to 40% HbF in erythroid progeny of edited human CD34 cells in vitro. We now find that the targeted ablation of a single, specific GATAA motif in the BCL11A intronic enhancer does not affect in vitro erythroid differentiation, but reproducibly (n=6) activates fetal globin transcription in erythroid progeny of modified CD34 cells; importantly, at similar levels of on-target marking in CD34+ cells, these effects on fetal globin mRNA are comparable to those resulting from ZFN-driven coding knockout of BCL11A itself. We demonstrate reproducible (n=8), high-efficiency (up to 82%; average, 69%) ZFN-driven marking at the enhancer in peripheral blood mobilized human CD34 cells at clinical production scale (>1e8 cells) in a GMP-compliant setting for which we use a clinical-grade electroporation device to deliver nuclease-encoding transcribed mRNA ex vivo. Using erythroid colony assay genotyping we find that up to 70% of the cells in the resulting population are biallelically modified at the target locus, while ~10% remain wild-type, and find comparably high levels of marking in research-scale preparations of CD34 cells from patients with β-thalassemia. We observe robust long-term (18-24 week) engraftment and multilineage differentiation of genome-edited cells in immunodeficient mice, similar to control cells, and equivalent modification at the targeted enhancer locus at all timepoints in both differentiated (CD19+, CD3+, CD33+) and more primitive progenitor (CD34+CD38low) cells of human origin purified from bone marrow of long-term-engrafted animals. Our findings support clinical development of enhancer editing as a treatment of the β hemoglobinopathies with autologous hematopoietic stem cell transplant. Disclosures Urnov: Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Reik:Sangamo BioSciences: Employment, Equity Ownership, Patents & Royalties: Patent applications have been filed based on this work. Vierstra:University of Washington: Patents & Royalties: Patent applications have been filed based on this work. Chang:Biogen: Employment, Equity Ownership. Zhou:Sangamo BioSciences: Employment, Equity Ownership. Mich:Sangamo BioSciences: Employment, Equity Ownership. Adrian:Cellerant Therapeutics: Equity Ownership; Sangamo BioSciences: Employment, Equity Ownership. Fox:Sangamo BioSciences: Employment, Equity Ownership. Tan:Biogen: Employment, Equity Ownership. Craig:Sangamo BioSciences: Employment, Equity Ownership. Rebar:Sangamo BioSciences: Employment. Stamatoyannopoulos:University of Washington: Patents & Royalties: Patent applications have been filed based on this work.. Jiang:Biogen: Employment, Equity Ownership.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 610-610 ◽  
Author(s):  
John F. Tisdale ◽  
Robert E. Donahue ◽  
Naoya Uchida ◽  
Bradley R Pearse ◽  
Sean M McDonough ◽  
...  

Autologous hematopoietic stem cell transplantation (Auto-HSCT) with gene-modification techniques represents a potential cure for multiple genetic blood diseases. Despite its broad curative potential, auto-gene modified HSCT is currently limited due to morbidity/mortality from cytotoxic chemotherapy-based conditioning, including risks of secondary malignancies, organ toxicity, and infertility. To overcome these limitations, we have developed antibody drug conjugates (ADC) targeting CD117 (C-KIT) to specifically deplete the hematopoietic stem and progenitor cells (HSPC) prior to auto-gene modified HSCT. We have previously shown that the anti-CD117 ADC is highly effective at killing human CD117+ cells in vitro and in vivo (Pearse et al., Blood 2018 132:3314). To validate CD117 as an appropriate antigen for targeted ADC-mediated depletion prior to HSCT, we developed an optimized non-human primate (NHP) tool anti-CD117 ADC and evaluated it in an auto-gene modified HSCT in the rhesus macaque model. The tool CD117-ADC is potent on primary human and NHP CD34+ cells in vitro with EC50 of 0.2 and 0.09 pM respectively (Figure 1A). Humanized NSG mice treated with the tool CD117-ADC had full depletion of human HSPCs in the bone marrow 21 days after a single administration of the ADC, while maintaining the peripheral immune cells. We next tested the efficacy and safety of the tool CD117-ADC in NHPs. A single administration of the tool CD117-ADC was fully myeloablative (>99% HSPC depletion) and comparable to HSPC depletion observed following busulfan conditioning (6 mg/kg, once daily for 4 consecutive days). There was no effect on the peripheral and bone marrow lymphocytes and the ADC was well tolerated. To facilitate the use in HSCT, the tool CD117-ADC was engineered to have a fast clearance and in this study the half-life was <10 hours. Based on these encouraging results, we explored whether the tool CD117-ADC could enable engraftment of autologous gene modified hematopoietic stem cells in the rhesus macaque model. A single rhesus macaque was mobilized with granulocyte-colony stimulating factor (G-CSF, 20 mcg/kg/day x 5) and plerixafor (1 mg/kg on day 5 of G-CSF) prior to apheresis. The isolated CD34+ cells were transduced with a lentivirus encoding the β-globin gene and cryopreserved. The tool CD117-ADC was dosed on day -6 and the cryopreserved gene modified cells were thawed and infused (3.3 x 106 CD34+ cells/kg) on day 0. A bone marrow aspirate analyzed on the day of infusion (day 0) demonstrated >99% depletion of the HSPCs and preserved of the bone marrow lymphocytes (Figure 1B). The primate engrafted neutrophils and platelets on day 8 and 10 respectively, and the peripheral lymphocytes were maintained throughout the transplant (Figure 1C). The gene marking in the granulocytes was detectable at day 9, and additional follow up and data from additional animals will be presented. In summary, we have developed a tool CD117 ADC that shows potent activity on NHP CD34+ cells. This optimized CD117-ADC is fully myeloablative with a single dose in NHPs, has a favorable safety profile, spares the immune system and is cleared rapidly as designed. In a rhesus model of autologous gene modified HSCT, a single dose of the ADC enables engraftment of auto-gene modified HSC. These proof of concept studies validate the use of CD117-ADC for targeted HSPC depletion prior to transplant and support its use as a new conditioning agent for autologous gene modified HSCT. This targeted approach for safer conditioning could improve the risk benefit profile for patients undergoing stem cell transplant and enable more patients to benefit from these potentially curative therapies. Disclosures Pearse: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. McDonough:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Proctor:Magenta Therapeutics: Employment, Equity Ownership. Panwar:Magenta Therapeutics: Employment, Equity Ownership. Sarma:Magenta Therapeutics: Employment, Equity Ownership. Kien:Magenta Therapeutics: Employment, Equity Ownership. Latimer:Magenta Therapeutics: Employment, Equity Ownership. Dushime:Magenta Therapeutics: Employment, Equity Ownership. Hyzy:Magenta Therapeutics: Employment, Equity Ownership. Brooks:Magenta Therapeutics: Employment, Equity Ownership. Palchaudhuri:Magenta Therapeutics: Employment, Equity Ownership. Li:Magenta Therapeutics: Employment, Equity Ownership. Sawant:Magenta Therapeutics: Employment, Equity Ownership. McDonagh:Magenta Therapeutics: Employment. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1961-1961
Author(s):  
John F. DiPersio ◽  
Jonathan Hoggatt ◽  
Steven Devine ◽  
Lukasz Biernat ◽  
Haley Howell ◽  
...  

Background Granulocyte colony-stimulating factor (G-CSF) is the standard of care for mobilization of hematopoietic stem cells (HSCs). G-CSF requires 4-7 days of injections and often multiple aphereses to acquire sufficient CD34+ cells for transplant. The number of CD34+ HSCs mobilized can be variable and patients who fail to mobilize enough CD34+ cells are treated with the combination of G-CSF plus plerixafor. G-CSF use is associated with bone pain, nausea, headaches, fatigue, rare episodes of splenic rupture, and is contraindicated for patients with autoimmune and sickle cell disease. MGTA-145 (GroβT) is a CXCR2 agonist. MGTA-145, in combination with plerixafor, a CXCR4 inhibitor, has the potential to rapidly and reliably mobilize robust numbers of HSCs with a single dose and same-day apheresis for transplant that is free from G-CSF. MGTA-145 plus plerixafor work synergistically to rapidly mobilize HSCs in both mice and non-human primates (Hoggatt, Cell 2018; Goncalves, Blood 2018). Based on these data, Magenta initiated a Phase 1 dose-escalating study to evaluate the safety, PK and PD of MGTA-145 as a single agent and in combination with plerixafor. Methods This study consists of four parts. In Part A, healthy volunteers were dosed with MGTA-145 (0.0075 - 0.3 mg/kg) or placebo. In Part B, MGTA-145 dose levels from Part A were selected for use in combination with a clinically approved dose of plerixafor. In Part C, a single dose MGTA-145 plus plerixafor will be administered on day 1 and day 2. In Part D, MGTA-145 plus plerixafor will be administered followed by apheresis. Results MGTA-145 monotherapy was well tolerated in all subjects dosed (Table 1) with no significant adverse events. Some subjects experienced mild (Grade 1) transient lower back pain that dissipated within minutes. In the ongoing study, the combination of MGTA-145 with plerixafor was well tolerated, with some donors experiencing Grade 1 and 2 gastrointestinal adverse events commonly observed with plerixafor alone. Pharmacokinetic (PK) exposure and maximum plasma concentrations increased dose proportionally and were not affected by plerixafor (Fig 1A). Monotherapy of MGTA-145 resulted in an immediate increase in neutrophils (Fig 1B) and release of plasma MMP-9 (Fig 1C). Neutrophil mobilization plateaued within 1-hour post MGTA-145 at doses greater than 0.03 mg/kg. This plateau was followed by a rebound of neutrophil mobilization which correlated with re-expression of CXCR2 and presence of MGTA-145 at pharmacologically active levels. Markers of neutrophil activation were relatively unchanged (<2-fold vs baseline). A rapid and statistically significant increase in CD34+ cells occurred @ 0.03 and 0.075 mg/kg of MGTA-145 (p < 0.01) relative to placebo with peak mobilization (Fig 1D) 30 minutes post MGTA-145 (7-fold above baseline @ 0.03 mg/kg). To date, the combination of MGTA-145 plus plerixafor mobilized >20/µl CD34s in 92% (11/12) subjects compared to 50% (2/4) subjects receiving plerixafor alone. Preliminary data show that there was a significant increase in fold change relative to baseline in CD34+ cells (27x vs 13x) and phenotypic CD34+CD90+CD45RA- HSCs (38x vs 22x) mobilized by MGTA-145 with plerixafor. Mobilized CD34+ cells were detectable at 15 minutes with peak mobilization shifted 2 - 4 hours earlier for the combination vs plerixafor alone (4 - 6h vs 8 - 12h). Detailed results of single dose administration of MGTA-145 and plerixafor given on one day as well as also on two sequential days will be presented along with fully characterized graft analysis post apheresis from subjects given MGTA-145 and plerixafor. Conclusions MGTA-145 is safe and well tolerated, as a monotherapy and in combination with plerixafor and induced rapid and robust mobilization of significant numbers of HSCs with a single dose in all subjects to date. Kinetics of CD34+ cell mobilization for the combination was immediate (4x increase vs no change for plerixafor alone @ 15 min) suggesting the mechanism of action of MGTA-145 plus plerixafor is different from plerixafor alone. Preliminary data demonstrate that MGTA-145 when combined with plerixafor results in a significant increase in CD34+ fold change relative to plerixafor alone. Magenta Therapeutics intends to develop MGTA-145 as a first line mobilization product for blood cancers, autoimmune and genetic diseases and plans a Phase 2 study in multiple myeloma and non-Hodgkin lymphoma in 2020. Disclosures DiPersio: Magenta Therapeutics: Equity Ownership; NeoImmune Tech: Research Funding; Cellworks Group, Inc.: Membership on an entity's Board of Directors or advisory committees; Karyopharm Therapeutics: Consultancy; Incyte: Consultancy, Research Funding; RiverVest Venture Partners Arch Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees; WUGEN: Equity Ownership, Patents & Royalties, Research Funding; Macrogenics: Research Funding, Speakers Bureau; Bioline Rx: Research Funding, Speakers Bureau; Celgene: Consultancy; Amphivena Therapeutics: Consultancy, Research Funding. Hoggatt:Magenta Therapeutics: Consultancy, Equity Ownership, Research Funding. Devine:Kiadis Pharma: Other: Protocol development (via institution); Bristol Myers: Other: Grant for monitoring support & travel support; Magenta Therapeutics: Other: Travel support for advisory board; My employer (National Marrow Donor Program) has equity interest in Magenta. Biernat:Medpace, Inc.: Employment. Howell:Magenta Therapeutics: Employment, Equity Ownership. Schmelmer:Magenta Therapeutics: Employment, Equity Ownership. Neale:Magenta Therapeutics: Employment, Equity Ownership. Boitano:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Goncalves:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Raffel:Magenta Therapeutics: Employment, Equity Ownership. Falahee:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Morrow:Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Davis:Magenta Therapeutics: Employment, Equity Ownership.


Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 659-659
Author(s):  
Kevin A. Goncalves ◽  
Megan D. Hoban ◽  
Jennifer L. Proctor ◽  
Hillary L. Adams ◽  
Sharon L. Hyzy ◽  
...  

Abstract Background. The ability to expand human hematopoietic stem cells (HSCs) has the potential to improve outcomes in HSC transplantation and increase the dose of gene-modified HSCs. While many approaches have been reported to expand HSCs, a direct comparison of the various methods to expand transplantable HSCs has not been published and clinical outcome data for the various methods is incomplete. In the present study, we compared several small molecule approaches reported to expand human HSCs including HDAC inhibitors, the aryl hydrocarbon antagonist, SR1, and UM171, a small molecule with unknown mechanism, for the ability to expand phenotypic HSC during in vitro culture and to expand cells that engraft NSG mice. Although all strategies increased the number of phenotypic HSC (CD34+CD90+CD45RA-) in vitro, SR1 was the most effective method to increase the number of NOD-SCID engrafting cells. Importantly, we found that HDAC inhibitors and UM171 upregulated phenotypic stem cell markers on downstream progenitors, suggesting that these compounds do not expand true HSCs. Methods. Small-molecules, SR1, HDAC inhibitors (BG45, CAY10398, CAY10433, CAY10603, Entinostat, HC Toxin, LMK235, PCI-34051, Pyroxamide, Romidepsin, SAHA, Scriptaid, TMP269, Trichostatin A, or Valproic Acid) and UM171 were titrated and then evaluated at their optimal concentrations in the presence of cytokines (TPO, SCF, FLT3L, and IL6) for the ability to expand human mobilized peripheral blood (mPB)-derived CD34+ cells ex vivo . Immunophenotype and cell numbers were assessed by flow cytometry following a 7-day expansion assay in 10-point dose-response (10 µM to 0.5 nM). HSC function was evaluated by enumeration of colony forming units in methylcellulose and a subset of the compounds were evaluated by transplanting expanded cells into sub-lethally irradiated NSG mice to assess engraftment potential in vivo . All cells expanded with compounds were compared to uncultured or vehicle-cultured cells. Results. Following 7 days of expansion, SR1 (5-fold), UM171 (4-fold), or HDAC inhibitors (&gt;3-35-fold) resulted in an increase in CD34+CD90+CD45RA- number relative to cells cultured with cytokines alone; however, only SR1 (18-fold) and UM171 (8-fold) demonstrated enhanced engraftment in NSG mice. Interestingly, while HDAC inhibitors and UM171 gave the most robust increase in the number and frequency of CD34+CD90+CD45RA- cells during in vitro culture, these methods were inferior to SR1 at increasing NSG engrafting cells. The increase in CD34+CD90+CD45RA- cells observed during in vitro culture suggested that these compounds may be generating a false phenotype by upregulating CD90 and down-regulating CD45RA on progenitors that were originally CD34+CD90-CD45RA+. We tested this hypothesis by sorting CD34+CD90-CD45RA+ cells and culturing these with the various compounds. These experiments confirmed that both HDAC inhibitors (33-100 fold) and UM171 (28-fold) led to upregulation of CD90 on CD34+CD90-CD45RA+ cells after 4 days in culture. Since approximately 90% of the starting CD34+ cells were CD90-, these data suggest that most of the CD34+CD90+CD45RA- cells in cultures with HDAC inhibitors and UM171 arise from upregulation of CD90 rather than expansion of true CD34+CD90+CD45RA- cells and may explain the disconnect between in vitro HSC phenotype and NSG engraftment in vivo . This was further confirmed by evaluation of colony forming unit frequency of CD34+CD90-CD45RA+ cells after culture with compounds. Conclusions. We have showed that AHR antagonism is optimal for expanding functional human HSCs using the NSG engraftment model. We also demonstrated that UM171 and HDAC inhibitors upregulate phenotypic HSC markers on downstream progenitors. This could explain the discrepancy between impressive in vitro phenotypic expansion and insufficient functional activity in the NSG mouse model. Therefore, these data suggest caution when interpreting in vitro expansion phenotypes without confirmatory functional transplantation data, especially as these approaches move into clinical trials in patients. Disclosures Goncalves: Magenta Therapeutics: Employment, Equity Ownership. Hoban: Magenta Therapeutics: Employment, Equity Ownership. Proctor: Magenta Therapeutics: Employment, Equity Ownership. Adams: Magenta Therapeutics: Employment, Equity Ownership. Hyzy: Magenta Therapeutics: Employment, Equity Ownership. Boitano: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties. Cooke: Magenta Therapeutics: Employment, Equity Ownership, Patents & Royalties.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1650-1650
Author(s):  
Tsila Zuckerman ◽  
Stela Gengrinovitch ◽  
Ruth Ben-Yakar ◽  
Ron Hoffman ◽  
Israel Henig ◽  
...  

Abstract Introduction: Therapy of acute myeloid leukemia (AML) has not changed significantly during several decades. High-dose cytarabine, although used as the first-line treatment for AML since 1970s and as a second-line treatment for acute lymphoblastic leukemia (ALL), is associated with severe side effects, such as cerebellar toxicity and bone marrow suppression. Hence, while the incidence of AML increases with age, doses of cytarabine are significantly attenuated or the drug is entirely excluded from the regimen used in older adults due to its potential toxicities, particularly in individuals with hepatic or renal dysfunction. Astarabine is a new composition of cytarabine covalently bound to asparagine. It is designed to target cytarabine to leukemic blasts, thus avoiding extramedullary toxicity. Leukemic cells, which are dependent on an external source of amino acids in general and asparagine in particular, due to their high metabolic rate, have a relatively increased uptake of Astarabine. Inside the blasts, Astarabine is cleaved to cytarabine, enabling targeted killing and relative sparing of normal hematopoiesis. As such, Astarabine may serve as an ideal therapy for leukemia, particularly for delivering high doses of cytarabine to medically unfit or older adults who otherwise can be given supportive therapy only. The aim of this study was to evaluate the safety and optimal dose of Astarabine in refractory/relapsed or medically unfit patients with acute leukemia. Methods: This Phase I/IIa prospective open label study enrolled patients aged ≥18 years with relapsed/refractory or newly-diagnosed acute leukemia unfit for intensive therapy, as judged by the treating physician. The study was approved by the Rambam IRB (approval #0384-11). Patients were enrolled into 6 Astarabine escalating-dose cohorts, each composed of 3-6 patients. Treatment was administered as a 1-hour single daily infusion for 6 days. For cohorts 1-4, Astarabine doses for each infusion were 0.5g/m2, 1.5g/m2, 3g/m2 and 4.5g/m2. The doses were reduced by 50% for patients >50 years. Since dose limiting toxicity (DLT) was not reached in cohorts 1-4, the study was extended to include cohorts 5 and 6 with daily Astarabine doses of 4.5g/m2 and 6g/m2, respectively, with no dose reduction for patients >50 years old. Results: The outcome of 15 patients is reported herein. Six patients with a median age of 64 years (range 27-81) had refractory/relapsed AML, 9 patients with a median age of 80 years (range 70-90) were newly diagnosed (secondary AML - 6, de-novo AML - 2, de-novo ALL - 1) and unfit for intensive therapy. Astarabine treatment was well-tolerated. Two patients died (one from pneumonia and one from sudden death 2 weeks from end of treatment) before completing 30 days post-treatment and hence were excluded from the outcome analysis. Response to the treatment was observed in the bone marrow of 6 of the 7 newly-diagnosed patients for whom bone marrow analysis was available, 3 of whom had a continuous complete remission (CR) for 4 (ongoing), 8, and 10 months post-treatment, and 3 had a continuous partial remission (PR) for 3,7, and 7 (ongoing) months. The median overall survival (OS) of the patients with CR/PR is 7 months to date (table 1). No significant response was observed in the relapsed/refractory patients, with a median OS of 2.5 months. Twelve patients died from disease progression. Conclusions: Astarabine, a new composition of leukemia-targeted cytarabine, is safe and very well tolerated, even in patients over 80 years of age, resulting in response in 6 of 7 newly diagnosed patients with acute leukemia. To the best of our knowledge, this is the first report permitting high-dose of cytarabine, considered a cornerstone of leukemia therapy, to be given to a population of patients that heretofore did not have this option. Further dose escalation studies are currently ongoing at a cytarabine-equivalent dose of 4.5 and 6 g/m2/day. A phase II study is planned to confirm these encouraging results and define the use of Astarabine for patients otherwise unable to receive high doses of cytarabine. Disclosures Zuckerman: BioSight Ltd: Consultancy, Research Funding. Gengrinovitch:BioSight Ltd: Employment, Equity Ownership, Patents & Royalties: Inventor all of the patents. Ben-Yakar:BioSight Ltd: Consultancy, Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Inventor of all patents.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1528-1528
Author(s):  
Sebastian Stasik ◽  
Jan Moritz Middeke ◽  
Michael Kramer ◽  
Christoph Rollig ◽  
Alwin Krämer ◽  
...  

Abstract Purpose: The enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase and key epigenetic regulator involved in transcriptional repression and embryonic development. Loss of EZH2 activity by inactivating mutations is associated with poor prognosis in myeloid malignancies such as MDS. More recently, EZH2 inactivation was shown to induce chemoresistance in acute myeloid leukemia (AML) (Göllner et al., 2017). Data on the frequency and prognostic role of EZH2-mutations in AML are rare and mostly confined to smaller cohorts. To investigate the prevalence and prognostic impact of this alteration in more detail, we analyzed a large cohort of AML patients (n = 1604) for EZH2 mutations. Patients and Methods: All patients analyzed had newly diagnosed AML, were registered in clinical protocols of the Study Alliance Leukemia (SAL) (AML96, AML2003 or AML60+, SORAML) and had available material at diagnosis. Screening for EZH2 mutations and associated alterations was done using Next-Generation Sequencing (NGS) (TruSight Myeloid Sequencing Panel, Illumina) on an Illumina MiSeq-system using bone marrow or peripheral blood. Detection was conducted with a defined cut-off of 5% variant allele frequency (VAF). All samples below the predefined threshold were classified as EZH2 wild type (wt). Patient clinical characteristics and co-mutations were analyzed according to the mutational status. Furthermore, multivariate analysis was used to identify the impact of EZH2 mutations on outcome. Results: EZH2-mutations were found in 63 of 1604 (4%) patients, with a median VAF of 44% (range 6-97%; median coverage 3077x). Mutations were detected within several exons (2-6; 8-12; 14-20) with highest frequencies in exons 17 and 18 (29%). The majority of detected mutations (71% missense and 29% nonsense/frameshift) were single nucleotide variants (SNVs) (87%), followed by small indel mutations. Descriptive statistics of clinical parameters and associated co-mutations revealed significant differences between EZH2-mut and -wt patients. At diagnosis, patients with EZH2 mutations were significantly older (median age 59 yrs) than EZH2-wt patients (median 56 yrs; p=0.044). In addition, significantly fewer EZH2-mut patients (71%) were diagnosed with de novo AML compared to EZH2-wt patients (84%; p=0.036). Accordingly, EZH2-mut patients had a higher rate of secondary acute myeloid leukemia (sAML) (21%), evolving from prior MDS or after prior chemotherapy (tAML) (8%; p=0.036). Also, bone marrow (and blood) blast counts differed between the two groups (EZH2-mut patients had significantly lower BM and PB blast counts; p=0.013). In contrast, no differences were observed for WBC counts, karyotype, ECOG performance status and ELN-2017 risk category compared to EZH2-wt patients. Based on cytogenetics according to the 2017 ELN criteria, 35% of EZH2-mut patients were categorized with favorable risk, 28% had intermediate and 37% adverse risk. No association was seen with -7/7q-. In the group of EZH2-mut AML patients, significantly higher rates of co-mutations were detected in RUNX1 (25%), ASXL1 (22%) and NRAS (25%) compared to EZH2-wt patients (with 10%; 8% and 15%, respectively). Vice versa, concomitant mutations in NPM1 were (non-significantly) more common in EZH2-wt patients (33%) vs EZH2-mut patients (21%). For other frequently mutated genes in AML there was no major difference between EZH2-mut and -wt patients, e.g. FLT3ITD (13%), FLT3TKD (10%) and CEBPA (24%), as well as genes encoding epigenetic modifiers, namely, DNMT3A (21%), IDH1/2 (11/14%), and TET2 (21%). The correlation of EZH2 mutational status with clinical outcomes showed no effect of EZH2 mutations on the rate of complete remission (CR), relapse free survival (RFS) and overall survival (OS) (with a median OS of 18.4 and 17.1 months for EZH2-mut and -wt patients, respectively) in the univariate analyses. Likewise, the multivariate analysis with clinical variable such as age, cytogenetics and WBC using Cox proportional hazard regression, revealed that EZH2 mutations were not an independent risk factor for OS or RFS. Conclusion EZH mutations are recurrent alterations in patients with AML. The association with certain clinical factors and typical mutations such as RUNX1 and ASXL1 points to the fact that these mutations are associated with secondary AML. Our data do not indicate that EZH2 mutations represent an independent prognostic factor. Disclosures Middeke: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rollig:Bayer: Research Funding; Janssen: Research Funding. Scholl:Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Abbivie: Other: Travel support; Alexion: Other: Travel support; MDS: Other: Travel support; Novartis: Other: Travel support; Deutsche Krebshilfe: Research Funding; Carreras Foundation: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees. Hochhaus:Pfizer: Research Funding; Incyte: Research Funding; Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Takeda: Research Funding. Brümmendorf:Janssen: Consultancy; Takeda: Consultancy; Novartis: Consultancy, Research Funding; Merck: Consultancy; Pfizer: Consultancy, Research Funding. Burchert:AOP Orphan: Honoraria, Research Funding; Bayer: Research Funding; Pfizer: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Novartis: Research Funding. Krause:Novartis: Research Funding. Hänel:Amgen: Honoraria; Roche: Honoraria; Takeda: Honoraria; Novartis: Honoraria. Platzbecker:Celgene: Research Funding. Mayer:Eisai: Research Funding; Novartis: Research Funding; Roche: Research Funding; Johnson & Johnson: Research Funding; Affimed: Research Funding. Serve:Bayer: Research Funding. Ehninger:Cellex Gesellschaft fuer Zellgewinnung mbH: Employment, Equity Ownership; Bayer: Research Funding; GEMoaB Monoclonals GmbH: Employment, Equity Ownership. Thiede:AgenDix: Other: Ownership; Novartis: Honoraria, Research Funding.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1770-1770 ◽  
Author(s):  
Roger M Lyons ◽  
Richard A. Larson ◽  
Michael A. Kosmo ◽  
Sunil Gandhi ◽  
Delong Liu ◽  
...  

Abstract Abstract 1770 Poster Board I-796 Introduction Romiplostim is a peptibody protein designed to increase platelet production by binding to and activating the thrombopoietin receptor. Low platelet counts in patients with myelodysplastic syndromes (MDS) may be due to the underlying disease or to treatment with disease-modifying agents, and platelet transfusions are often the only treatment for clinically significant thrombocytopenia (CST) or bleeding. This was a phase 2 multi-center, randomized, double-blind, placebo-controlled, dose-finding study that evaluated the effect of romiplostim on the incidence of clinically significant thrombocytopenic events (grade 3 or 4 thrombocytopenia and/or receipt of platelet transfusions) and the safety of romiplostim in patients with low or intermediate risk MDS receiving lenalidomide. Patients and Methods Patients who were ≥18 years old, had MDS by bone marrow exam and WHO criteria, had low or Intermediate-1 risk category MDS using the IPSS, and were planning to receive lenalidomide were eligible. Patients were randomized 1:1:1 into treatment groups receiving placebo, 500 μg romiplostim, or 750 μg romiplostim by weekly subcutaneous injections in combination with lenalidomide (one 10 mg capsule by mouth daily for each 28-day cycle). Treatments continued for a total of four cycles. Results The median age of the 39 randomized patients was 74 years (range, 39 to 90); 15 (39%) had platelet counts <50 × 109/L, and 7 (18%) had del(5q). We report trends due to baseline imbalances between treatment groups, likely due to the limited sample size. The overall incidence rates of CST appeared to be greater in the placebo group than either romiplostim group (Table). In contrast to the placebo patients, median platelet counts remained above 50 × 109/L in both the 500 μg and 750 μg romiplostim groups for the treatment period. The incidence of platelet transfusions appeared to be lower in the 500 μg romiplostim group, and the incidence of adverse events was comparable between all of the groups. No deaths were reported during the treatment period. Twelve patients (31%) discontinued the study. Disease progression to AML was reported in 1 patient in the romiplostim 500 μg group. The patient withdrew consent and discontinued the study. No bone marrow was available to confirm AML by protocol-defined criteria. Fewer lenalidomide dose reductions and delays due to thrombocytopenia were seen in both of the romiplostim treated groups. The proportion of patients who achieved an MDS treatment response was 8%, 36% and 15% for the placebo, 500 μg romiplostim, and 750 μg romiplostim groups, respectively. MDS response rates appeared higher in the romiplostim group, regardless of baseline del(5q) status. Baseline imbalance between groups due to the small sample size limited our interpretation of the data. Conclusions Romiplostim appeared to be well-tolerated in low and intermediate risk MDS patients receiving lenalidomide. This preliminary information suggests that romiplostim may reduce the rate of clinically significant thrombocytopenic events in these patients while increasing platelet counts and decreasing the incidence of lenalidomide dose reductions and delays due to thrombocytopenia Disclosures Lyons: GlaxoSmithKline: Consultancy, Speakers Bureau; Johnson&Johnson: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy; Amgen Inc.: Consultancy, Honoraria, Research Funding, Speakers Bureau. Off Label Use: Use of romiplostim to treat Thrombocytopenia in MDS. Larson:Amgen Inc.: Equity Ownership, Research Funding. Liu:Amgen Inc.: Honoraria, Research Funding. Hu:Amgen Inc.: Employment, Equity Ownership. Franklin:Amgen Inc.: Employment, Equity Ownership. Berger:Amgen Inc.: Employment, Equity Ownership.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4544-4544
Author(s):  
Ronan T. Swords ◽  
Kevin R. Kelly ◽  
Devalingam Mahalingam ◽  
Stephen C. Cohen ◽  
Larry J. Miller ◽  
...  

Abstract Abstract 4544 Background The importance of bone marrow aspiration and biopsy in the evaluation of hematopoietic and non-hematopoietic disorders is well established. Recently, a new FDA-cleared battery powered bone marrow biopsy system was developed to allow operators access to the bone marrow space quickly and efficiently. Aims The first aim of this study was to evaluate the quality of core specimens using the new powered device compared to specimens obtained using the traditional manual technique in a swine model. The second aim was to evaluate the safety and efficacy of the device in patients presenting for outpatient hematology clinic visits. Materials and Methods For the pre-clinical evaluation of the device, three anesthetized pigs were used for the study. The powered device (OnControl, Vidacare Corporation, San Antonio, TX, USA) was comprised of a battery powered driver and needle set. The manual device used was a T-Handle Jamshidi bone marrow biopsy needle (Cardinal Health, Dublin, OH, USA). Core biopsy samples obtained were assessed for length and sample quality and then submitted for analysis to a pathologist blinded to the device used. The clinical evaluation of the device was conducted in accordance with practice guidelines and directions for use. Data collection included insertion success, time from insertion to removal, specimen quality, operator satisfaction with control/function of the device and overall operator satisfaction based on a scoring system (0-5; 0=totally unacceptable, 5=outstanding). Results Twenty six samples were collected from the swine model (19 samples using the powered device and 9 using the manual technique). No cellular artifact or thermal damage was reported in any of the samples obtained. The mean lengths for samples obtained using the powered and manual techniques were respectively 19.4mm±1.6mm and 18.6mm±5.3mm. For the clinical evaluation of the device, 16 patients were recruited from 2 centers. Mean insertion time was 11.25±3.39 seconds and mean time from needle contact with skin to needle removal was 38.5±13.94 seconds. No complications were reported. Five operators rated the overall use of the device as outstanding in 75% of cases. Conclusions In this study, the manual and powered samples were equivalent in specimen quality. The powered device however, captured longer biopsies when compared to the manual technique. In the patients evaluated, the device was easy to use as well as being safe and effective. The mean procedural time was significantly faster than previously reported with a manual technique. A randomized study of the powered device compared to the manual technique is underway. Disclosures: Swords: Vidacare Corporation: Research Funding. Kelly:Vidacare Corporation: Research Funding. Mahalingam:Vidacare Corporation: Research Funding. Cohen:Vidacare Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Miller:Vidacare Corporation: Employment, Equity Ownership. Philbeck:Vidacare Corporation: Employment, Equity Ownership. Brenner:Vidacare Corporation: Consultancy, Research Funding. Giles:Vidacare Corporation: Research Funding.


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