Hemophilia A: Intrathymic Delivery for Tolerance and Longterm Expression of FVIII

A 型血友病：胸腺内递送以实现 FVIII 的耐受性和长期表达

基本信息

批准号：
7324891
负责人：
WILLIAM C RASCHKE
金额：
$ 14.99万
依托单位：
VIROGENICS, INC.
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2009-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7324891
关键词：
Address Age Age-Years Animal Model Animals Antibodies Antibody Formation Antigens Applications Grants B-Lymphocytes Biodistribution Biological Assay Blood Bone Marrow Caring Cells Cessation of life Child Chronic Complication DNA Data Development Diagnosis Diagnostic Disadvantaged Disease Educational process of instructing Equilibrium Evaluation Exposure to Factor VIII Family Felidae Feline Immunodeficiency Virus Future Gene Expression Gene Transfer Genome Goals HIV Heart Hemophilia A Hemorrhage Human Immune Immune response Immune system Immunocompetent Immunologic Deficiency Syndromes Immunosuppression Implant In Situ Inbred BALB C Mice Individual Infusion procedures Injection of therapeutic agent Intravenous Kidney Knockout Mice Lentivirus Vector Life Liver Lung Lymphocyte Lymphoid Cell Measures Mediating Messenger RNA Monitor Mus Newborn Infant Numbers Operative Surgical Procedures Organ Patients Phase Phase I Clinical Trials Plasma Plasma Proteins Polymerase Chain Reaction Population Preparation Prevention Primates Production Proliferating Property Proteins Purpose Rate Replacement Therapy Research Research Personnel Reverse Transcriptase Polymerase Chain Reaction Risk Route Safety Sampling Screening procedure Site Spleen Standards of Weights and Measures Stromal Cells Surgical complication System T-Cell Proliferation T-Lymphocyte Testing Therapeutic Therapeutic Effect Therapeutic immunosuppression Thymus Gland Time Tissues Toxic effect Transgenes Venous Viral Viral Genes Viral Vector Virus Work antibody inhibitor arthropathies base cell type cellular engineering concept cost cytokine day experience gene therapy human F8 protein immunogenic immunogenicity inhibitor/antagonist lymph nodes mRNA Expression man mouse model neonate novel novel therapeutics particle peripheral blood pre-clinical prevent prophylactic protein expression ran GTP-Binding Protein research study therapeutic protein thymocyte transduction efficiency transgene expression treatment effect vector

项目摘要

DESCRIPTION (provided by applicant): The current standard of care for hemophilia A is treatment with intravenous human factor VIII (hFVIII) protein infusions, either prophylactically or during bleeding episodes. A major disadvantage for both prophylactic and on- demand FVIII protein infusions is the formation of anti-human FVIII antibodies (inhibitors) in about 25% of treated individuals. Inhibitor formation is one of the most difficult complications of this bleeding disorder since inhibitors neutralize hFVIII and thus thwart hFVIII replacement therapy. The long-term goal of this project is to develop a therapy that can avoid the serious problem of inhibitor formation and provide constant amounts of FVIII protein. This proposal will exploit the unique properties of the thymus to induce tolerance to foreign proteins (hFVIII) by intrathymic injection of a lentiviral vector encoding human FVIII. Intrathymic injection of lentiviral vectors efficiently transduces the long-lived thymic stromal cells, which are the target cell types for sustained hFVIII protein production. Due to the immunological properties of the thymus, this approach should facilitate long-term expression of hFVIII without elimination by the immune system. The general feasibility of this approach is supported by several studies. For example, MHC-incompatible bone marrow stromal cells engineered to express a transgene and implanted into the thymus will not undergo immune rejection and can secrete the transgene product long-term. Work spanning forty years has shown that intrathymic exposure to foreign antigen can induce tolerance to a subsequent graft in the periphery. With respect to the delivery system, a non-primate lentiviral vector derived from Feline Immunodeficiency Virus (FIV) provides excellent transduction efficiency of a variety of cells and organs including stromal cells. Together, these results show that exploiting the immune privileged status of the thymus as a site for protein production has the potential to revolutionize treatment for hemophilia A. This proposal will explore intrathymic FIV-hFVIII vector injection to prevent inhibitor formation. FIV vectors will be used since they efficiently transduce non-proliferating cells including those that make up the thymic stroma, and stably integrate into the host genome potentially allowing lifelong expression of the transgene. Additional benefits are the viral particle's low toxicity, low immunogenicity and the lack of any viral genes after integration into the host genome. The hypothesis that the combination of an efficient and relatively non-immunogenic vector system with the intrathymic route of delivery will prevent inhibitor formation and allow secretion of hFVIII protein from transduced thymic stroma into peripheral blood will be tested. To demonstrate the feasibility of this approach for long-term hFVIII therapy, hFVIII protein and possible anti-hFVIII antibodies will be measured over six months in a mouse model, possible effects of FIV- hFVIII intrathymic injection on thymopoiesis will be assessed, and organs other than thymus will be analyzed for vector transduction and hFVIII mRNA expression. Data from these experiments will indicate whether intrathymic injection of FIV-hFVIII vectors will provide a valuable treatment alternative specifically aimed at reduced inhibitor formation. Exceeding the scope of this grant application, the proposed proof-of-concept studies will form the basis for future studies including a comparison of the intrathymic with the iv route of administration and the potential of intrathymic injection to reduce pre-existing inhibitors. The use of gene therapy to correct hemophilia A introduces the expression of the factor VIII protein. Factor VIII protein is low or missing in hemophilia patients and therefore a foreign protein for most patients. Exposure to any foreign protein runs the risk of the recipient patient mounting an immune response to the new protein. Such immune responses neutralize the therapeutic protein rendering it ineffective. Approximately 25% of all hemophilia A patients suffer from inhibitors, which leads to severe complications including uncontrolled bleeding, chronic joint disease and premature death. The proposed research will evaluate and optimize a means to "teach" the immune system that the new therapeutic protein is not foreign so that an immune response will not be generated and the function of the factor VIII protein to stop uncontrolled bleeding will be preserved.

描述（由申请人提供）：血友病A的当前护理标准是静脉内人体因子VIII（HFVIII）蛋白输注，无论是预防性还是在出血发作期间。预防性和需求FVIII蛋白输注的主要缺点是在约25％的治疗个体中形成抗人FVIII抗体（抑制剂）。抑制剂形成是这种出血疾病最困难的并发症之一，因为抑制剂中和HFVIII，从而阻止HFVIII替代疗法。该项目的长期目标是开发一种可以避免抑制剂形成的严重问题并提供恒定量的FVIII蛋白的治疗方法。该建议将利用胸腺的独特特性来诱导外国蛋白质（HFVIII）耐受性，并通过静脉内注射编码人FVIII的慢病毒载体注射。静脉注射慢病毒载体有效地转导长寿命的胸腺基质细胞，这些细胞是持续HFVIII蛋白产生的靶细胞类型。由于胸腺的免疫学特性，这种方法应促进HFVIII的长期表达，而不会被免疫系统消除。多项研究支持了这种方法的一般可行性。例如，设计用于表达转基因并植入胸腺的MHC兼容的骨髓基质细胞不会进行免疫排斥，并且可以长期分泌转基因产物。跨越四十年的工作表明，内舌暴露于外国抗原可以诱导对周围的随后移植物的耐受性。关于递送系统，从猫免疫缺陷病毒（FIV）衍生出的非青春期慢病毒载体为包括基质细胞在内的各种细胞和器官提供了出色的转导效率。总之，这些结果表明，利用胸腺的免疫特权状态作为蛋白质产生的部位有可能彻底改变血友病A的治疗。该提案将探索胸膜内膜的FIV-HFVIII载体注射以防止抑制剂形成。 FIV载体将被使用，因为它们有效地传递了非增殖细胞，包括构成胸腺基质的细胞，并稳定地整合到宿主基因组中，潜在地允许转基因的终身表达。其他好处是病毒颗粒的低毒性，低免疫原性以及整合到宿主基因组后缺乏任何病毒基因。假设有效且相对非免疫原性载体系统与胸膜内递送途径的组合将预防抑制剂形成，并允许将HFVIII蛋白分泌到转导的胸腺基质中，将其分泌为周围血液。为了证明这种方法对长期HFVIII治疗的可行性，HFVIII蛋白和可能的抗HFVIII抗体将在六个月内在小鼠模型中测量，FIV-HFVIII内膜内的可能影响将评估胸腺膜激素对胸腺膜激素的影响以及其他thymus以外的thymus and thymus and vection。这些实验的数据将表明静脉内注射FIV-HFVIII载体是否会提供一种有价值的治疗方法，该替代方案专门用于降低抑制剂形成。拟议的概念概念证明研究超出了本赠款施加的范围，将构成未来研究的基础，包括对静脉反应与IV给药途径进行比较，以及静脉注射的潜力减少预先存在的抑制剂。使用基因疗法纠正血友病A引入了VIII因子蛋白的表达。血友病患者的VIII因子VIII蛋白低或缺失，因此大多数患者是异物。暴露于任何外国蛋白质会承担接受对新蛋白质免疫反应的受体患者的风险。这种免疫反应中和治疗蛋白使其无效。大约有25％的所有血友病患者患有抑制剂，这会导致严重的并发症，包括不受控制的出血，慢性关节疾病和过早死亡。拟议的研究将评估和优化一种“教授”免疫系统的方法，即新的治疗蛋白不是外来的，因此不会产生免疫反应，并且VIII因子蛋白的功能将保留不受控制的出血。