scholarly journals Lentiviral Mediated Gene Therapy for Pyruvate Kinase Deficiency: Interim Results of a Global Phase 1 Study for Adult and Pediatric Patients

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 563-563
Author(s):  
Ami J Shah ◽  
José Luis López Lorenzo ◽  
Susana Navarro ◽  
Julián Sevilla ◽  
Lucía Llanos ◽  
...  

Abstract Background: Pyruvate kinase deficiency (PKD) is a rare inherited hemolytic anemia caused by mutations in the PKLR gene resulting in decreased red cell pyruvate kinase activity and impaired erythrocyte metabolism. Manifestations include anemia, reticulocytosis, splenomegaly and iron overload, and may be life-threatening in severely affected individuals. PKD represents a significant unmet medical need as current treatments are palliative and limited to blood transfusions, chelation therapy, and splenectomy which are associated with significant side effects. Preclinical studies in a clinically relevant PKD murine model have demonstrated that infusion of gene-modified Lin− bone marrow (BM) cells may ameliorate PKD phenotype. Based on compelling preclinical data, a global Phase 1 clinical trial RP-L301-0119 (NCT04105166) is underway to evaluate the feasibility and safety of lentiviral mediated gene therapy in adult and pediatric subjects with severe PKD. Methods: Six adult and pediatric patients with severe PKD (defined as severe and/or transfusion-dependent anemia despite prior splenectomy) will be enrolled. Peripheral blood (PB) hematopoietic stem cells (HSCs) are collected on 2 consecutive days via apheresis after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. HSCs are enriched, transduced with PGK-coRPK-WPRE lentiviral vector (LV), and cryopreserved. Following release testing of the investigational product (IP), RP-L301, myeloablative therapeutic drug monitoring (TDM) busulfan is administered over 4 days. RP-L301 is then thawed and infused. Patients are followed for safety assessments, including replication competent lentivirus (RCL) and insertion site analysis (ISA), and for efficacy parameters including PB and BM genetic correction, decrease in transfusion requirements, clinically significant improvement in anemia, and reduction of hemolysis for 2 years post-infusion. Results: As of May 2021, 2 adult patients with severe anemia have received RP-L301. Patient 1 (age 31 years) received 3.9x106 CD34+ cells/kg with mean vector copy number (VCN) of 2.73. Patient 2 (age 47 years) received 2.4x106 CD34+ cells/kg with mean VCN of 2.08. Despite baseline hemoglobin (Hb) levels in the 7.0-7.5 g/dL range, both patients displayed normal-range hemoglobin (Hb), improved hemolysis markers, and have required no red blood cell transfusions post-engraftment at 9- and 6- months follow-up. Both report improved quality of life. PB mononuclear cell VCNs for both patients were >2.0 at last evaluated timepoint (6- and 3-months post-treatment, respectively). No serious adverse events have been attributed to RP-L301. Updated safety and efficacy data will be presented. Conclusions: Hematopoietic stem cell mobilization using G-CSF and plerixafor is feasible and effective in adult PKD patients. RP-L301 was successfully manufactured to meet the required specifications for the Phase 1 clinical study and administered without short-term infusion related complications. Efficacy was demonstrated by normalized Hb associated with engraftment confirmed by PB and BM VCN. Disclosures Shah: OrchardTherapeutics: Membership on an entity's Board of Directors or advisory committees, Other: Dr. Shah currently serves on the medical advisory board for Orchard Therapeutics . Navarro: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: Dr. Navarro has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Sevilla: Miltenyi: Consultancy; Novartis: Consultancy; Amgen: Consultancy; Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Sevilla is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, and may be entitled to receive financial benefits from the licensing of such patents.; SOBI: Consultancy. Glader: Agios: Consultancy. Quintana Bustamante: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company. Beard: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Rao: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren: Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Bueren is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, may be entitled to receive financial benefits from the licensing of such patents and receives funding for research., Patents & Royalties, Research Funding. Schwartz: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Segovia: Rocket Pharmaceuticals, Inc.: Consultancy, Research Funding.

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 29-29
Author(s):  
Sara Fañanas-Baquero ◽  
Oscar Quintana Bustamante ◽  
Daniel P. Dever ◽  
Omaira Alberquilla ◽  
Rebeca Sanchez-Dominguez ◽  
...  

Pyruvate kinase deficiency (PKD) is an autosomal recessive disorder caused by mutations in the PKLR gene that lead to a reduction of the erythroid pyruvate kinase (RPK) protein activity, which causes an energetic imbalance in PKD erythroid cells. This disease is associated with reticulocytosis, splenomegaly and iron overload, and may be life-threatening in severely affected patients. In selected cases, allogeneic Hematopoietic Stem Cell Transplantation has been shown to correct the disorder. Therefore, autologous HSCT of genetically corrected cells will offer a durable and curative therapeutic option. In fact, a global Phase I clinical trial (clinicaltrials.gov #NCT04105166) is underway to evaluate the feasibility and safety of lentiviral mediated gene therapy with severe PKD. Looking for a guided integration of the exogenous therapeutic DNA sequences, herein we conducted a gene editing approach to correct PKD in human Hematopoietic Stem Cells (HSCs). We developed a knock-in approach to insert either a TurboGFP expression cassette or a promotor-less therapeutic codon optimized RPK cDNA (coRPK) at the genomic starting site of the PKLR gene, a gene editing strategy that will correct most of the mutations present in PKD patients. This gene editing approach combines RNP nucleofection and adeno-associated viral vector (AAV6) mediated delivery of homologous donors. In order to assess the safety of the proposed gene editing approach, we performed GUIDE-Seq and rhAmpSeqTM analyses of different single guide RNAs targeting the PKLR starting site. We found PKLR sgRNAs that showed a high targeting efficiency, up to 40% targeted hematopoietic progenitors (in vitro semisolid colony forming units) and a safety profile, with no off-targets detected above threshold values (0.1%) and in the absence of cellular toxicity, when applied to healthy cord blood CD34+ (CB-CD34+) cells. These gene-edited CB-CD34+ cells engrafted efficiently in both primary and secondary immunodeficient NSG recipient mice, demonstrating the gene editing in long-term hematopoietic repopulating HSCs. Furthermore, we evaluated the therapeutic potential of this gene editing strategy to restore the energetic imbalance in erythroid cells derived from PKD patients. CD34+ cells from 4 different PKD patients, were purified, nucleofected with PKLR sgRNA and transduced with AAV-coRPK donor. In vitro differentiated erythroid cells derived from edited PKD CD34+ expressed coRPK mRNA and restored their energetic defect up to normal values obtained in in vitro differentiated erythroid cells from healthy donor cells. Moreover, gene edited mobilized Peripheral Blood CD34+ (mPB-CD34+) cells from a PKD patient engrafted efficiently in immunodeficient NBSGW mice, having human cells that showed the specific integration of coRPK donor 2 months post-transplant. Overall, these results demonstrate the feasibility and safety of PKLR gene editing in human HSPCs and, therefore, its potential clinical application for the treatment of PKD patients. Disclosures Dever: Integral Medicines: Current Employment. Turk:Integrated DNA Technologies, Inc. (IDT): Current Employment, Current equity holder in publicly-traded company. Bianchi:Agios Pharmaceuticals: Other: Scientific Advisor. Behlke:Integrated DNA Technologies, Inc. (IDT): Current Employment, Current equity holder in publicly-traded company. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from this company., Patents & Royalties, Research Funding. Segovia:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from the Company., Patents & Royalties, Research Funding.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2932-2932
Author(s):  
Donald B. Kohn ◽  
Claire Booth ◽  
Julián Sevilla ◽  
Gayatri R Rao ◽  
Elena Almarza ◽  
...  

Abstract Background: Leukocyte Adhesion Deficiency-I (LAD-I) is a rare disorder of neutrophil adhesion resulting from ITGB2 mutations encoding for the β2-integrin component, CD18. Severe LAD-I (CD18 <2% of polymorphonuclear [PMN] cells) is characterized by severe infections, impaired wound healing, and childhood mortality. Allogeneic hematopoietic stem cell transplant (alloHSCT) is potentially curative; however, its efficacy is limited by donor availability and risk of graft-versus-host disease (GVHD) and graft failure. RP-L201-0318 (NCT03812263), a phase 1/2 open-label trial currently underway, employs autologous CD34+ cells transduced with a lentiviral vector (LV) carrying the ITGB2 gene (cDNA) Methods: Pediatric patients ≥ 3 months old with severe LAD-I are eligible. HSCs are collected via apheresis after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor and transduced with Chim-CD18-WPRE-LV. Myeloablative therapeutic drug monitoring (TDM) busulfan conditioning precedes RP-L201 infusion. Patients are followed for safety and efficacy (i.e., survival to age 2 and at least 1-year post-infusion, increase in PMN leukocyte CD18 expression to at least 10%, peripheral blood [PB] vector copy number [VCN], decrease in infections/hospitalizations, and resolution of skin or periodontal abnormalities). Results: Seven patients (ages 5mos-9yrs) have received RP-L201; all with follow-up ≥3 to 18 months. RP-L201 cell doses ranged from 2.8x106 to 6.5x106 CD34+ cells/kg with VCN from 1.8-3.8 copies/cell. No serious RP-L201 related treatment-emergent adverse events were reported. PB PMN CD18 expression in Patient 1 at 18-months post-treatment was 40% (vs. < 1% at baseline), with PB VCN of 1.44. Baseline skin lesions resolved with no new lesions reported. CD18 expression in the subsequent 6 patients has been 25-80% in neutrophils and stable for each patient from 3 to up to 18 months post-treatment. No new infections have been reported in patients post-infusion. The safety profile of RP-L102 remains highly favorable with no serious adverse events (SAEs) attributed to the investigational product (IP). Conclusion: RP-L201 leads to durable neutrophil CD18 expression and improved clinical course. Additional patient treatment is ongoing in 2021. Disclosures Kohn: UC Regents: Patents & Royalties; Pluto Immunotherapeutics: Membership on an entity's Board of Directors or advisory committees; Allogene: Membership on an entity's Board of Directors or advisory committees; ImmunoVec: Membership on an entity's Board of Directors or advisory committees; Lyrik Therapeutics: Membership on an entity's Board of Directors or advisory committees; MyoGene Bio: Membership on an entity's Board of Directors or advisory committees; Bluebird Bio: Membership on an entity's Board of Directors or advisory committees; Sangamo Biosciences: Membership on an entity's Board of Directors or advisory committees. Booth: GSK: Honoraria; Takeda: Honoraria; SOBI: Consultancy, Honoraria; Orchard Therapeutics: Consultancy, Honoraria; Rocket Pharmaceuticals, Inc.: Consultancy. Sevilla: Miltenyi: Consultancy; Novartis: Consultancy; Amgen: Consultancy; Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Sevilla is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, and may be entitled to receive financial benefits from the licensing of such patents.; SOBI: Consultancy. Rao: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Almarza: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. de Oliveira: Orchard Therapeutics: Research Funding; Bluebird Bio: Research Funding. Law: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Beard: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Thrasher: Orchard Therapeutics: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Generation bio: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; 4Bio Capital: Consultancy, Membership on an entity's Board of Directors or advisory committees; Rocket Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees. Bueren: Rocket Pharmaceuticals, Inc.: Consultancy, Other: J.Bueren is an inventor on patents on lentiviral vectors filed by CIEMAT, CIBERER and Fundación Jiménez Díaz, may be entitled to receive financial benefits from the licensing of such patents and receives funding for research., Patents & Royalties, Research Funding. Schwartz: Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 47-47
Author(s):  
José Luis López Lorenzo ◽  
Susana Navarro ◽  
Ami J Shah ◽  
Maria Grazia Roncarolo ◽  
Julián Sevilla ◽  
...  

Introduction: Pyruvate Kinase Deficiency (PKD) is a rare inherited hemolytic anemia that is caused by mutations in the PKLR gene leading to decreased red cell pyruvate kinase (RPK) activity and impaired erythrocyte metabolism. The disorder is characterized by anemia, reticulocytosis, splenomegaly and iron overload, and may be life-threatening in severely affected individuals. PKD represents a significant unmet medical need as current therapies are palliative and limited to chronic blood transfusions, iron chelation therapy, and splenectomy. The side effects of these supportive treatments include iron overload, end-organ damage and increased infection risks. AG-348, an allosteric activator of RPK, is under evaluation in clinical trials, predominantly in less severely-afflicted transfusion-independent patients. Allogeneic hematopoietic stem cell transplantation (HSCT) has been performed in selected cases and resulted in transfusion independence, suggesting that the disorder may be reversed when an adequate level of hematopoietic stem and progenitor cells (HSPCs) harboring a corrected PKLR gene engraft in the bone marrow (BM). The therapeutic efficacy of allogeneic transplant is limited by the availability of a suitable donor and transplant-associated toxicities. Preclinical studies conducted in a clinically relevant PKD murine model have demonstrated the safety and efficacy of Lin- BM cells transduced with the therapeutic lentiviral vector, PGK-coRPK-WPRE, in ameliorating the PKD phenotype. More specifically, transplantation of transduced cells resulted in increased erythrocyte survival, decreased reticulocytosis, and improvement in the secondary manifestations of hemolytic anemia, including splenomegaly and hepatic iron overload. Based on compelling preclinical data, a global Phase 1 clinical trial RP-L301-0119 (clinicaltrials.gov#NCT04105166) is underway to evaluate the feasibility and safety of lentiviral mediated gene therapy in adults and pediatric subjects with severe PKD. Methods: 6 subjects with severe PKD (defined as having a history of severe and/or transfusion-dependent anemia despite prior splenectomy) will be enrolled in the Phase 1 study; the first 2 subjects will be adults (age ≥18-<50 years), followed by 2 older pediatric subjects (age ≥12-17 years) once initial safety has been established. Subsequently, 2 younger pediatric subjects (age ≥8-11 years) will be enrolled. Peripheral blood (PB) hematopoietic stem cells are collected on two consecutive days via apheresis after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. CD34+ HSPCs are enriched, transduced with PGK-coRPK-WPRE lentiviral vector (LV), and cryopreserved. Following final release testing of the investigational product (IP), RP-L301, myeloablative conditioning with therapeutic drug monitoring (TDM)-guided busulfan is administered over 4 days. RP-L301 is then thawed and infused. Patients are followed for safety assessments, including replication competent lentivirus (RCL) and insertion site analysis (ISA), and for efficacy parameters including PB and BM genetic correction, decrease in transfusion requirements, clinically significant improvement in anemia, and reduction of hemolysis. Results: An adult female PKD subject (age 31 years) with significant anemia and transfusion requirement has received treatment as of July 2020. Mobilization and apheresis procedures were performed successfully and busulfan conditioning was administered at the target area under the curve (AUC). IP consisted of 3.9×106 CD34+ cells/kg body weight, with a mean vector copy number (VCN) of 2.73. Safety and preliminary efficacy results will be available at the time of presentation. Conclusions: Efficacy in pre-clinical models indicates promising potential for clinical gene therapy in severe PKDHematopoietic stem cell mobilization using G-CSF and plerixafor appears feasible and effective in adult PKD patientsIP was successfully manufactured to meet the required specifications for the Phase 1 clinical study and administered without short-term infusion related complications Disclosures Navarro: Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: SN has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Sevilla:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company. Glader:Agios Pharmaceuticals, Inc.: Consultancy. Beard:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from this company., Patents & Royalties, Research Funding. Rao:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Schwartz:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Segovia:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from the Company., Patents & Royalties, Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 15-15 ◽  
Author(s):  
Donald B. Kohn ◽  
Gayatri R Rao ◽  
Elena Almarza ◽  
Dayna Terrazas ◽  
Eileen Nicoletti ◽  
...  

Introduction: LAD-I is a rare inherited disorder of leukocyte (primarily neutrophil) adhesion to endothelial cell surfaces, migration, and chemotaxis resulting from ITGB2 gene mutations encoding for the β2-integrin component, CD18. Severe LAD-I (i.e., CD18 expression on <2% of PMNs) is characterized by recurrent severe infections, impaired wound healing, and childhood mortality. Although allogeneic hematopoietic stem cell transplant (alloHSCT) is potentially curative, its utilization and efficacy are limited by HLA-matched donor availability and risk of graft-versus-host disease (GVHD). RP-L201-0318 (clinical trials.gov # NCT03812263) is a phase 1/2 open-label clinical trial evaluating the safety and efficacy of autologous CD34+ cells transduced with a lentiviral vector (LV) carrying the ITGB2 gene encoding for CD18 (Chim-CD18-WPRE) in severe LAD-I. Methods: Pediatric patients ≥ 3 months old with severe LAD-I (demonstrated by CD18 expression on <2% PMNs and at least 1 prior significant bacterial or fungal infection) are eligible. Peripheral blood (PB) HSCs are collected via apheresis after mobilization with granulocyte-colony stimulating factor (G-CSF) and Plerixafor. CD34+ cells are selected, transduced with Chim-CD18-WPRE LV, and cryopreserved. Myeloablative conditioning with busulfan (with therapeutic drug monitoring (TDM) to adjust dosing to enable target area under the curve (AUC)) is administered, followed by infusion of the investigational drug product (RP-L201). Patients are followed for safety assessments (i.e., replication competent lentivirus (RCL) and insertion site analysis (ISA)), and efficacy -- survival to age 2 and at least 1-year post-infusion without alloHSCT, increase in neutrophil CD18 expression to at least 10%, PB vector copy number (VCN), decrease in infections and/or hospitalizations, and resolution of skin or periodontal abnormalities. Results: Two patients (ages 9 and 3) were treated in Phase 1. Both have a history of recurrent severe infections, documented ITGB2 mutations, and baseline CD18, CD11a, and CD11b expression < 1%. Mobilization and apheresis procedures were performed successfully and busulfan was administered at the target AUC. Investigational product comprised of 4.2x106 CD34+ cells/kg with VCN of 3.8 copies/cell (liquid culture) for Patient 1 and 2.8x106 CD34+ cells/kg with VCN of 2.5 for Patient 2 and were infused without complications. No serious treatment-emergent adverse events were reported. Neutrophil engraftment was observed in < 3 weeks in both patients. For Patient 1, PB PMN CD18 expression 6 months post-treatment was 47% (sustained from 45% at 3-months, vs. < 1% at baseline), with PB VCN of 1.3. Skin lesions present at baseline were resolving with no new lesions. Replication competent lentiviral (RCL) testing at 3 months and 6 months post-infusion were negative. Safety and efficacy data 12-months post-treatment for Patient 1 and 6-months post-treatment for Patient 2 will be available at the time of presentation. Conclusion: Initial results from Phase 1 demonstrate preliminary safety and efficacy of RP-L201 for reversal of severe LAD-I. Enrollment of patients in the Phase 2 study is underway. Disclosures Kohn: Allogene Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Orchard Therapeutics: Consultancy, Patents & Royalties, Research Funding. Rao:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Almarza:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Beard:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Sevilla:Novartis: Other: Advisory Board; Sobi: Other: Advisory Board; Rocket Pharma: Consultancy; Amgen: Other: Advisory Board. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from this company., Patents & Royalties, Research Funding. Schwartz:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1864-1864
Author(s):  
Julie Kanter ◽  
John F. DiPersio ◽  
Patrick Leavey ◽  
David C. Shyr ◽  
Alexis A Thompson ◽  
...  

Abstract Background Sickle cell disease (SCD) is a recessive monogenic disease caused by a single point mutation in which glutamic acid replaces valine in Codon 6 of the human beta-globin gene (HBB) leading to the production of abnormal globin chains (HbS) that polymerize and cause erythrocytes to sickle. This results in hemolytic anemia, vaso-occlusion and organ damage, which leads to lifelong complications and early mortality. Allogeneic hematopoietic stem cell transplant (allo-HSCT) is the only known cure for SCD, however, its use is limited by the lack of well-matched donors, need for immunosuppression, risk of graft versus host disease and graft rejection. GPH101 is an investigational, autologous, hematopoietic stem cell (HSC) drug product (DP) designed to correct the SCD mutation in the HBB gene ex vivo using a high fidelity Cas9 (CRISPR associated protein 9) paired with an AAV6 (adeno-associated virus type 6) delivery template, efficiently harnessing the natural homology directed repair (HDR) cellular pathway. This approach has the potential to restore normal adult hemoglobin (HbA) production while simultaneously reducing HbS levels. In preclinical studies, HBB gene correction in SCD donor HSCs resulted in ≥60% of gene-corrected alleles in vitro with minimal off-target effects. Gene corrected cells were successfully differentiated toward the erythroid lineage and produced ≥70% HbA in vitro. Long-term engraftment of gene-corrected HSCs was demonstrated in vivo, following transplant into immunodeficient mice, with multi-lineage allelic gene correction frequencies well above the predicted curative threshold of 20%, with potential of this approach to be equivalent or superior to allo-HSCT. In addition, HSC-based correction in an SCD mouse model led to stable adult hemoglobin production, increased erythrocyte lifespan and reduction in sickling morphology, demonstrating the therapeutic potential of this gene correction platform as a curative approach in SCD. Study Design and Methods CEDAR (NCT04819841) is a first-in-human, open-label, single-dose, multi-site Phase 1/2 clinical trial in participants with severe SCD designed to evaluate safety, efficacy and pharmacodynamics (PD) of GPH101. Approximately 15 adult (18-40 years) and adolescent (12-17 years) participants will be enrolled across 5 sites, with adolescent enrollment proceeding after a favorable assessment of adult safety data by a Safety Monitoring Committee. Participants must have a diagnosis of severe SCD (βS/βS), defined as ≥ 4 severe vaso-occlusive crises (VOCs) in the 2 years prior and/or ≥ 2 episodes of acute chest syndrome (ACS), in 2 years prior with at least 1 episode in the past year. Participants on chronic transfusion therapy may be eligible if required VOC and ACS criteria are met in the 2 years prior to the initiation of transfusions. Key exclusion criteria include availability of a 10/10 human leukocyte antigen-matched sibling donor, or prior receipt of HSCT or gene therapy. After eligibility confirmation including screening for pre-treatment cytogenetic abnormalities, participants will undergo plerixafor mobilization and apheresis, followed by CD34+ cell enrichment and cryopreservation, undertaken locally at each trial site before shipment to a centralized manufacturer for GPH101 production. After GPH101 release, participants will undergo eligibility reconfirmation prior to busulfan conditioning and DP infusion. Safety, efficacy and PD measurements will occur for 2 years post-infusion; a long-term follow up study will be offered to participants for an additional 13 years of monitoring. The primary endpoint for this study is safety, measured by the kinetics of HSC engraftment, transplant related mortality, overall survival and frequency and severity of adverse events. Secondary endpoints will explore efficacy and PD, including levels of globin expression as compared to baseline, gene correction rates, clinical manifestations of SCD (including VOC and ACS), laboratory parameters, complications and organ function. In addition, cerebral hemodynamics and oxygen delivery will be assessed by magnetic resonance techniques. Key exploratory endpoints include evaluation of patient-reported outcomes, erythrocyte function, on-target and off-target editing rates, and change from baseline in select SCD characteristics. Disclosures Kanter: Fulcrum Therapeutics, Inc.: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Forma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees; Beam: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Graphite Bio: Consultancy; GuidePoint Global: Honoraria; Fulcrum Tx: Consultancy. Thompson: Agios Pharmaceuticals: Consultancy; Graphite Bio: Research Funding; Vertex: Research Funding; Beam Therapeutics: Consultancy; Celgene: Consultancy, Research Funding; Biomarin: Research Funding; Baxalta: Research Funding; CRISPR Therapeutics: Research Funding; Global Blood Therapeutics: Current equity holder in publicly-traded company; bluebird bio: Consultancy, Research Funding; Novartis: Research Funding. Porteus: Versant Ventures: Consultancy; CRISPR Therapeutics: Current equity holder in publicly-traded company; Allogene Therapeutics: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Ziopharm: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Graphite Bio: Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Intondi: Graphite Bio: Current Employment, Current equity holder in publicly-traded company; Global Blood Therapeutics: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Lahiri: Graphite Bio: Current Employment, Current equity holder in publicly-traded company. Dever: Graphite Bio: Current Employment, Current equity holder in publicly-traded company. Petrusich: bluebird bio: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Graphite Bio: Current Employment, Current equity holder in publicly-traded company. Lehrer-Graiwer: Global Blood Therapeutics: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Graphite Bio: Current Employment, Current equity holder in publicly-traded company.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 31-32
Author(s):  
Kevin A. Goncalves ◽  
Sharon L. Hyzy ◽  
Katelyn J. Hammond ◽  
Patrick C. Falahee ◽  
Haley Howell ◽  
...  

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 >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 >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<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<0.001, n=3 donors) and 11-fold higher engraftment compared to plerixafor mobilized grafts (p<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<0.01) or plerixafor (p<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 & 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.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 14-14
Author(s):  
Agnieszka Czechowicz ◽  
Rajni Agarwal ◽  
Julián Sevilla ◽  
Paula Río ◽  
Susana Navarro ◽  
...  

Background: Fanconi anemia (FA) is a rare inherited disorder of defective cellular deoxyribonucleic acid (DNA) repair, associated with developmental abnormalities and characterized by progressive bone marrow failure (BMF) and a predisposition to hematologic malignancies and solid tumors. Approximately 60-70% of all cases result from mutations in the Fanconi Anemia Complementation Group A (FANCA) gene (FA-A). 80% of FA patients develop BMF within the first decade of life. Although allogeneic hematopoietic stem cell transplant (allo-HSCT) is a potentially curative treatment for BMF, its utilization and efficacy are limited by availability of suitable human leukocyte antigen (HLA)-matched donors, risk of graft-versus-host disease (GVHD) and transplant-related toxicities. Ex-vivo lentiviral mediated gene therapy of autologous FA-A CD34+ enriched hematopoietic stem and progenitor cells (HSPCs) has been shown to confer a survival advantage to gene-modified HSPCs in preclinical studies and, most recently, in the investigator initiated Phase 1/2 FANCOLEN-I clinical trial conducted in Madrid, Spain. Based on the highly favorable safety profile and promising preliminary efficacy data, global studies using "Process B" optimization including transduction enhancers, commercial-grade vector, and modified cell processing are underway. Herein, we report updated results from the US Phase 1 clinical trial and preliminary data from the global Phase 2 study in US and EU. Design and Methods: Subjects with a confirmed FANCA gene mutation aged 1 year or older, with no HLA-matched sibling donor and at least 30 CD34+ cells/µL in bone marrow (BM) were eligible for enrollment. Peripheral blood (PB) mononuclear cells were collected via leucocytapheresis on two consecutive days after mobilization with granulocyte-colony stimulating factor (G-CSF) and plerixafor. CD34+ HSPCs were enriched, transduced with a lentiviral vector (PGK-FANCA-WPRE) and infused fresh (not cryopreserved) without any antecedent conditioning. Patients are being followed for 3 years post-infusion for safety assessments (replication competent lentivirus (RCL), insertion site analysis (ISA)) and to ascertain evidence of efficacy (increasing PB vector copy number (VCN) and BM mitomycin-C (MMC) resistance), along with stabilization/correction of cytopenias. Results: As of August 2020, 2 subjects (aged 5 and 6 years) have received RP-L102 infusion on the Phase 1 study with over 12 months of follow up. Preliminary evidence of gene marking in PB post-RP-L102 infusion at various timepoints has been observed in both subjects. Increased bone marrow (BM) mitomycin-C (MMC) resistance post treatment has also been identified in at least 1 subject. Subject L102-001-1001 has had blood count stabilization over the 12 months following gene therapy administration. Subject L102-001-1002's course has been complicated by influenza B infection with concomitant decreases in blood counts requiring red blood cell transfusions. Transfusion requirements have decreased following resolution of infection. Since November 2019, 5 additional subjects have been enrolled onto the global Phase 2 study and received investigational infusion. Updated preliminary safety and efficacy data including PB VCN, blood counts and BM MMC resistance will be available at the time of presentation for subjects with over 12 months of follow up; drug product (DP) information (VCN and CD34+ cell dose) will be available for all treated subjects. Conclusions: DP has been successfully manufactured in the Phase I (N=2) and Phase 2 (N=5) to meet the required specificationsSafety profile of RP-L102 continues to be highly favorable.Evidence of engraftment has been seen in at least 1 subject with follow up of at least 12 months as indicated by PB genetic markings and increasing BM CFC MMC resistance; 12+ months of follow-up may be required to observe the proliferative advantage of transduced HSPCs. Disclosures Czechowicz: Rocket Pharmaceuticals, Inc.: Research Funding. Sevilla:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company. Río:Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: PR has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Navarro:Rocket Pharmaceuticals, Inc.: Current equity holder in publicly-traded company, Other: SN has licensed medicinal products and receives research funding and equity from Rocket Pharmaceuticals, Inc., Patents & Royalties, Research Funding. Beard:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Law:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Choi:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Zeini:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Nicoletti:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Wagner:BlueRock: Research Funding; Magenta Therapeutics: Consultancy, Research Funding; Gadeta: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company. Schwartz:Rocket Pharmaceuticals, Inc.: Current Employment, Current equity holder in publicly-traded company. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Current equity holder in publicly-traded company, Other: Consultant for Rocket Pharmaceuticals, Inc. and has licensed medicinal products and receives research funding and equity from this company., Patents & Royalties, Research Funding.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4627-4627
Author(s):  
Paula Rio ◽  
Susana Navarro ◽  
Rebeca Sanchez-Dominguez ◽  
Jose C Segovia ◽  
Wei Wang ◽  
...  

Nine Fanconi anemia patients complementation group A (FA-A), age 2-6 years, have been infused with autologous hematopoietic cells after genetic correction with the therapeutic PGK-FANCA.Wpre* lentiviral vector. In all instances patients underwent CD34+ cell mobilization with G-CSF and plerixafor and were subsequently infused in the absence of any pre-conditioning regimen, in order to avoid genotoxic side effects in a population characterized by DNA repair defects and cancer predisposition. The first four patients were treated between January 2016 and March 2017 and were infused with an estimated number of 170,000 and 410,000 transduced CD34+ cells/Kg. The other five patients were treated more recently with cell numbers that ranged between 50,000 to 1.6x106 corrected CD34+ cells/kg. The analyses of the first four patients showed the presence of corrected cells both in BM and PB after six months post-infusion and progressive increases of gene marking were observed thereafter in all these patients until the most recent follow-up (2 to >3 years post-infusion). Gene marking in BM CD34+ cells correlated with the survival of the CFCs to mitomycin-C, with levels up to 70% at 3 years post-infusion. Additionally, progressive decreases in the percentage of PB T cells with diepoxybutane-induced chromosomal breaks were observed in the patients with higher levels of gene marking. Similarly, stabilized PB cell counts have been observed in patients with higher percentages of gene corrected cells. Insertion site analyses revealed the absence of genotoxic events, and demonstrated the engraftment of pluripotent HSCs and a pattern of oligoclonal reconstitution, consistent with the number of infused corrected CD34+ cells and the absence of conditioning. In the five additional patients treated more recently, the presence of gene corrected PB cells has been confirmed; levels of gene marking have been consistent with data observed in the first four treated patients and with the number of infused CD34+ cells. Our results confirm the engraftment of gene corrected HSCs in non-conditioned FA-A patients, in some cases through more than 3 years of follow-up, suggesting the relevance of this therapeutic approach in FA. Disclosures Rio: Rocket Pharmaceuticals, Inc.: Equity Ownership, Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents, Research Funding. Navarro:Rocket Pharmaceuticals, Inc.: Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents. Segovia:Rocket Pharmaceuticals, Inc.: Equity Ownership, Honoraria, Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents, Research Funding. Wang:GeneWerk: Employment. Casado:Rocket Pharmaceuticals, Inc.: Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents. Galy:Genethon: Employment. Cavazzana:SmartImmune: Other: Founder. Schwartz:Rocket Pharmaceuticals: Employment, Equity Ownership. Schmidt:GeneWerk GmbH, Heidelberg, Gemrany: Equity Ownership; German Cancer Research Center, Heidelberg, Germany: Employment. Díaz de Heredia:Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Sevilla:Rocket Pharmaceuticals, Inc.: Honoraria, Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents; NOVARTIS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Rocket: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sobi: Membership on an entity's Board of Directors or advisory committees; Miltenyi Biotech: Honoraria. Bueren:Rocket Pharmaceuticals, Inc.: Consultancy, Equity Ownership, Patents & Royalties: Inventor on patents on lentiviral vectors filled by CIEMAT, CIBERER and F.J.D and may be entitled to receive financial benefits from the licensing of such patents, Research Funding.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5792-5792
Author(s):  
Oscar Quintana Bustamante ◽  
Sara Fañanas-Baquero ◽  
Daniel P. Dever ◽  
Alberquilla Omaira ◽  
Joab Camarena ◽  
...  

Abstract Pyruvate kinase deficiency (PKD) is the most common erythroid inherited enzymatic defect causing chronic nonspherocytic hemolytic anemia. PKD is an autosomal recessive disorder caused by mutations in the PKLR gene, which led in a total or partial reduction of the activity of the erythroid pyruvate kinase (RPK) protein. To date, more than 200 different mutations in the PKLR gene have been related with PKD. The disease is associated with reticulocytosis, splenomegaly and iron overload, and may be life-threatening in severely affected patients. Treatments for PKD are mainly palliative, including regular red blood cell transfusion, splenectomy and iron chelation therapy. Allogeneic hematopoietic stem cell transplant (HSCT) represents the only curative treatment for severely affected patients, so far. Autologous HSCT of genetically corrected cells would offer a durable and curative clinical option. Over the last years, gene editing has emerged as a promising gene therapy approach for blood cell disorders, where genetic alterations can be accurately corrected. The high level of correction got in hematopoietic progenitors and stem cells without remarkable off-target effects suggests that the clinical use of gene editing therapy to correct genetic hematopoietic diseases is highly likely in a short term. Here, we present two gene editing approaches to correct PKD in human hematopoietic cells based of specific point mutation correction and in cDNA knock-in of a codon optimized version the RPK cDNA. We have designed both strategies to maintain the endogenous regulation of RPK once the gene editing has been carried out. First, we designed specific sgRNA targeting NM_000298.5(PKLR):c.359C>T mutation reported as pathogenic in PKD patients, and a single-stranded donor oligonucleotide (ssODN) to correct this mutation. When both sgRNA/Cas9 ribonucleoprotein (RNP) and ssODN were nucleofected together in a heterozygous PKD patient-lymphoblastic cell line (PKD LCL), around 5% of total alleles were correctly edited. In a second strategy, we developed a knock-in gene editing strategy at the genomic starting site of the PKLR gene by combining RNP electroporation and the adeno-associated viral vector (AAV) delivery of the recombination matrix. Specific gRNAs generating up to 60% indels at the RPK starting site were generated. Two different AAV constructs flanked by specific homologous arms were generated to delivery either a TurboGFP expression cassette or a promotor-less therapeutic coRPK. Up to 60% donor integration and stable expression of turbo EGFP and of coRPK driven by PKLR endogenous promoter was obtained in K562 erythroleukemia cells. Similar gene editing efficacies were obtained in human CB-CD34+. Specific integration and stable expression of the transgenes were detected in up to 30% colony forming units (CFUs). Moreover, gene edited cells engrafted efficiently in NSG mice. These results demonstrate the feasibility of editing the PKLR locus in hematopoietic progenitors and hematopoietic stem cells at efficiencies that could be clinically applicable to treat Pyruvate Kinase deficiency. Disclosures Bueren: Rocket Pharmaceuticals Inc: Consultancy, Equity Ownership, Patents & Royalties, Research Funding. Porteus:CRISPR Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Segovia:Rocket Pharmaceuticals Inc: Consultancy, Equity Ownership, Patents & Royalties, Research Funding.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 698-698 ◽  
Author(s):  
John E. Wagner ◽  
Claudio G Brunstein ◽  
David McKenna ◽  
Darin Sumstad ◽  
Suzanne Maahs ◽  
...  

Abstract Background Despite enhanced tolerability of HLA mismatch, the reduced number of HSPC in an UCB graft limits the use of this stem cell source because of delayed hematopoietic recovery and increased risk of graft failure, particularly in adults. For this reason, we explored the effectiveness of SR1, an aryl hydrocarbon receptor antagonist, in the presence of cytokines to expand HSPC ex vivo prior to transplantation. Patients and Methods Nine patients with high-risk lympho-hematopoietic malignancy and two partially HLA (4-6/6)-matched UCB units were treated with cyclophosphamide 120 mg/kg, fludarabine 75 mg/m2 and total body irradiation 1320 cGy followed by double UCB transplantation. Unit1 (the unmanipulated larger of the two units) was infused followed by SR1-expanded UCB HSPC (derived from CD34 selected Unit2 cells cultured for 15 days) as well as rethawed CD34 negative Unit2 cells. GVHD prophylaxis was cyclosporine A and mycophenolate mofetil. Results Culture in the presence of SR1 resulted in a median of 248-fold (range, 66-446) expansion of CD34+ cells. The median number of CD34+ cells and CD3+ cells infused for Unit1 and Unit2 were 0.3 x 106/kg (range, 0.2-0.9) and 11.0 x 106/kg (range, 1.4-48.9), and 7.3 x 106/kg (range, 4.6-10.6) 2.8 x 106/kg (range, 0.4-4.9), respectively. There were no infusional toxicities noted. Based on a presumed graft-graft interaction, the HSC835 product predominated in 5 of 9 patients and resulted in sustained hematopoiesis for a median follow up of 303 days (range 140-401). The median time to neutrophil recovery (days to absolute neutrophil count of ≥500/uL) was shorter in recipients of HSC835 (i.e., 16 days [range, 6-23] versus 24 days [range, 22-30]) with the speed of neutrophil recovery correlating with the number of CD34+ cells infused (r2 = -0.87, p<0.05, Figure 1). With a median follow-up of 161 days (range, 40-401), six patients are alive. Primary causes of death were CMV pneumonitis, alveolar hemorrhage and interstitial pneumonitis in three patients. Conclusion The AHR antagonist SR1 is a potent inhibitor of HSC differentiation, resulting in marked expansion of HSPC. Hematopoietic reconstitution as early as day 6 is dependent on CD34+ cell dose in the expanded product, HSC835. Based on the long-term engraftment potential of HSC835 in half of the patients using the double UCB platform and the accelerated neutrophil recovery seen in patients recovering with HSC835, future patients will receive HSC835 alone eliminating the confounding graft-graft effects and potentially further reducing the time to neutrophil recovery. Disclosures: Wagner: Novartis: Research Funding. Brunstein:Novartis: Research Funding. McKenna:Novartis: Research Funding. Sumstad:Novartis: Research Funding. Maahs:Novartis: Employment. Boitano:Novartis: Employment. Cooke:Novartis: Employment. Bleul:Novartis: Employment.


Sign in / Sign up

Export Citation Format

Share Document