Molecular Chimerism Therapy for Hemophilia A

A 型血友病的分子嵌合疗法

• 批准号: 7446784
• 负责人: Robert G. Hawley
• 金额: $ 37.14万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7446784
• 关键词: A Mouse; Adverse event; Animal Model; Antibodies; B-domain-deleted factor VIII; Bleeding time procedure; Blood; Blood Cells; Blood Circulation; Candidate Disease Gene; Canis familiaris; Cells; Cellular biology; Chimerism; Chronic; Clinical Trials; Complication; Contusions; Defect; Development; Disease; Elements; Engineering; Enhancers; Enrollment; Factor VIII; Gene Delivery; Gene Transfer; Genetic; Hematoma; Hematopoietic; Hematopoietic stem cells; Hemophilia A; Hemorrhage; Human; Immune; Immunocompetent; Infusion procedures; Intracranial Hemorrhages; Joints; Knock-out; Laboratories; Life Expectancy; Link; Long Terminal Repeats; Modeling; Modification; Molecular; Mus; Muscle; Mutagenesis; Numbers; Operative Surgical Procedures; Patients; Plasma; Population; Prions; Production; Proteins; RNA Splicing; Recombinant Proteins; Refractory; Regulation; Regulator Genes; Replacement Therapy; Research; Research Personnel; Retroperitoneal Space; Retroviral Vector; Risk; Stem cell transplant; Stem cells; Subfamily lentivirinae; Therapeutic; Tissues; Transgenes; Transplantation; Trauma; Treatment Protocols; United States; Vertebral column; Virus; Week; X-Linked Severe Combined Immunodeficiency; base; clinically relevant; conditioning; design; enzyme replacement therapy; gene therapy; genotoxicity; human F8 protein; immunogenicity; improved; inhibitor/antagonist; leukemia; pre-clinical; promoter; prophylactic; recessive genetic trait; recombinant antihemophilic factor VIII; retroviral-mediated; success; transmission process; vector

DESCRIPTION (provided by applicant): Hemophilia A is an X-linked recessive genetic bleeding disorder caused by a deficiency or functional defect in coagulation factor VIII (FVIII). There is currently no cure for hemophilia A and patients receive infusion of FVIII concentrates or recombinant proteins at the time of bleeding. Although this treatment regimen has increased the life expectancy of hemophiliacs significantly, it is inconvenient and has potentially serious complications such as the development of inhibitory antibodies to FVIII, which occurs in approximately 25% of patients, rendering them refractory to further treatment. The objective of this research is to evaluate the curative efficacy of retroviral vectors encoding modified human FVIII transgenes targeted to hematopoietic stem cells (HSCs) in a murine hemophilia A model. HSCs are an attractive target cell population for hemophilia A gene therapy because they are readily accessible for ex vivo genetic modification and allow for the possibility of sustained expression of a FVIII transgene in circulating peripheral blood cells for the recipient's lifetime. Moreover, a potential benefit of targeting HSCs is the possibility of inducing immunological tolerance to the FVIII transgene product. For almost two decades, our laboratory has been designing and optimizing retroviral vectors for gene transfer studies of HSC biology and gene therapy modeling. In particular, our MSCV (murine stem cell virus) retroviral vector is in use in several HSC gene therapy trials currently underway in the United States. However, the emergence of adverse events in a French clinical trial for X- linked severe combined immunodeficiency disease demands a reevaluation of the risks of retroviral-induced mutagenesis. Therefore, building upon our recent success at achieving clinically-relevant FVIII plasma levels in hemophilia A mice by MSCV-based HSC-directed gene delivery, our Specific Aims are: (1) To further optimize FVIII transgene sequences for more efficient secretion in hematopoietic cells and decreased immunogenicity of the protein; (2) To develop nonmyeloablative HSC transplant conditioning regimens that allow sufficient levels of transgene molecular chimerism for long-term therapeutic FVIII production and tolerance induction; and (3) To create biologically safer FVIII retroviral vectors - devoid of transcriptional regulatory elements within their long terminal repeats and flanked by enhancer/promoter-blocking elements - displaying reduced HSC genotoxicity.

描述（由申请人提供）：A 型血友病是一种 X 连锁隐性遗传性出血性疾病，由凝血因子 VIII (FVIII) 缺乏或功能缺陷引起。目前 A 型血友病尚无治愈方法，患者在出血时接受 FVIII 浓缩物或重组蛋白输注。尽管这种治疗方案显着延长了血友病患者的预期寿命，但它不方便，并且可能存在严重的并发症，例如约 25% 的患者会产生 FVIII 抑制性抗体，使他们难以接受进一步治疗。本研究的目的是评估编码修饰的人 FVIII 转基因的逆转录病毒载体在小鼠 A 型血友病模型中针对造血干细胞 (HSC) 的疗效。 HSC 是血友病 A 基因治疗的一个有吸引力的靶细胞群，因为它们易于进行离体基因修饰，并且允许 FVIII 转基因在接受者一生中在循环外周血细胞中持续表达。此外，靶向HSC的一个潜在好处是可以诱导对FVIII转基因产物的免疫耐受。近二十年来，我们的实验室一直在设计和优化逆转录病毒载体，用于 HSC 生物学和基因治疗建模的基因转移研究。特别是，我们的 MSCV（鼠干细胞病毒）逆转录病毒载体正在美国目前正在进行的多项 HSC 基因治疗试验中使用。然而，法国一项 X 连锁严重联合免疫缺陷病临床试验中出现的不良事件要求重新评估逆转录病毒诱导突变的风险。因此，基于我们最近通过基于MSCV的HSC定向基因递送在血友病A小鼠中实现临床相关的FVIII血浆水平的成功，我们的具体目标是：（1）进一步优化FVIII转基因序列，以更有效地在造血细胞中分泌并降低蛋白质的免疫原性； (2) 开发非清髓性 HSC 移植预处理方案，使转基因分子嵌合水平达到足够水平，以实现长期治疗性 FVIII 产生和耐受诱导； (3) 创建生物学上更安全的 FVIII 逆转录病毒载体 - 在其长末端重复序列中缺乏转录调控元件，且侧翼为增强子/启动子阻断元件 - 显示降低的 HSC 遗传毒性。