A Phase I Clinical Trial Testing Feasibility of Hematopoietic Stem Cell Gene Therapy Using Platelet Factor VIII to Safely Improve Hemostasis for Severe Hemophilia A with Inhibitory Antibodies

I 期临床试验测试使用血小板因子 VIII 的造血干细胞基因治疗通过抑制性抗体安全改善严重甲型血友病止血的可行性

• 批准号: 10388261
• 负责人: MARY EAPEN
• 金额: $ 158.97万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-05 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10388261
• 关键词: Address; Affect; Alpha Granule; Animal Model; Animals; Antibodies; Autologous; Autologous Transplantation; Biological Assay; Blood; Blood Coagulation Disorders; Blood Platelets; Blood Vessels; Bone Marrow; Bypass; CD34 gene; Candidate Disease Gene; Canis familiaris; Capsid Proteins; Cell Survival; Cells; Chronic; Clinical; Clinical Trials; Coagulation Factor Deficiency; Continuous Infusion; DNA; Development; Ectopic Expression; Endothelial Cells; Engineering; Engraftment; Ensure; F8 gene; Factor VIII; Gene Transfer; Generations; Genes; Genetic Engineering; Genetic Transcription; Genome; HIV; Harvest; Health; Hematopoietic Stem Cell Transplantation; Hematopoietic stem cells; Hemophilia A; Hemorrhage; Hemostatic function; Hepatitis C; Human; Human Engineering; Immune; Immune mediated destruction; Immune response; Immune system; Immunosuppression; In Vitro; Individual; Infusion procedures; Inherited; Intravenous; Intravenous infusion procedures; Isoantibodies; Lead; Lentivirus Vector; Liver; Megakaryocytes; Methods; Molecular Genetics; Monitor; Morbidity - disease rate; Mus; Mutation; Nature; Odds Ratio; Other Genetics; Patients; Peripheral Blood Stem Cell; Persons; Phase I Clinical Trials; Plasma; Plasma Proteins; Prophylactic treatment; Proteins; Protocols documentation; Public Health; Recombinants; Recurrence; Regimen; Reporting; Resources; Reverse Transcriptase Polymerase Chain Reaction; Risk; Safety; Site; Source; Testing; Time; Tissues; Transcriptional Regulation; Transplantation; Transplantation Conditioning; Viral; X Chromosome; adeno-associated viral vector; canine model; cellular transduction; clinically significant; conditioning; conventional therapy; cost; enzyme replacement therapy; feasibility testing; first-in-human; gene replacement therapy; gene therapy; gene transfer vector; human study; immunogenic; improved; inhibitor; intravenous administration; joint injury; liver injury; meetings; mortality; mouse model; neutralizing antibody; novel; novel strategies; patient population; preclinical study; prevent; promoter; prophylactic; release factor; repaired; response; safety and feasibility; safety testing; standard care; stem cell gene therapy; stem cell genes; success; transduction efficiency; vascular injury; vector; viral transmission

PROJECT SUMMARY/ABSTRACT Patients with severe hemophilia A (PWHA) have a significant deficiency (<1% normal) in coagulation factor VIII (FVIII) that frequently causes recurrent spontaneous bleeding episodes leading to significant morbidity and mortality. Conventional therapy for HA employing the infusion of donor plasma FVIII cryoprecipitate product can be complicated by blood-borne transmission of viral illnesses (including HIV & hepatitis C). Use of recombinant FVIII (rFVIII) products has largely replaced the use of human-derived FVIII (because rFVIII prevents risk of viral transmission); however, plasma FVIII remains a valuable resource for HA throughout the world. Prophylactic therapy with FVIII requires the intravenous administration of FVIII 2-3 times weekly throughout a patient's lifetime. Unfortunately, recurrent intravenous access, low compliance, break-through bleeding, and joint-damage can occur despite FVIII prophylaxis. Additionally, ≈30% of HA develop allo-antibodies to FVIII replacement products that inhibit its ability to restore hemostasis. Thus, treatment of bleeding in these patients involves the administration of a costly “bypass” agent therapy (i.e., FVIII with immune suppression and/or FVIIa). Success has been achieved by inducing immune tolerization to FVIII in ≈60% of HA with inhibitory antibodies by several rigorous infusions of FVIII (often in the setting of prophylaxis with bypassing agents) although treatment for FVIII inhibitors remains a critical issue for HA patients. Due to its monogenic nature, HA is an ideal candidate for gene replacement therapy with the potential for correction of HA. Promising approaches include the targeted expression of human FVIII to the liver by intravenous infusion of naked DNA, the generation of a novel adeno-associated viral (AAV) vector equipped with less immunogenic coat proteins, and vectors incorporating small active forms of FVIII (that conform to the 4.4 kb packaging capacity of AAV). However, these strategies exclude individuals with 1) inhibitory antibodies to FVIII (≈30% PWHA), 2) pre-existing antibodies to the AAV (≈40% humans) and 3) chronic liver damage. To address this problem of considerable clinical significance, we propose a first-in-human phase I clinical trial employing a hematopoietic stem cell (HSC) gene therapy strategy that utilizes a lentiviral gene transfer vector encoding human FVIII under the transcriptional control of the megakaryocyte-specific ITGA2B gene promoter that targets expression of the FVIII gene in megakaryocytes causing ectopic synthesis, storage and regulated-release of factor VIII from α-granules of activated platelets precisely at the site of vascular injury. This proposal is supported by pre-clinical studies that showed platelet FVIII safely and efficiently improved hemostasis in murine and canine models of HA without the development of inhibitory antibodies to FVIII and even in the presence of pre-existing inhibitory antibodies to FVIII in mice. In summary, the proposed trial should reduce the risk of severe bleeding in PWHA with inhibitory antibodies to FVIII for whom current strategies employing factor bypassing agents, tolerizing therapy, and other genetic therapies are inadequate. 1

项目概要/摘要 严重 A 型血友病 (PWHA) 患者的凝血因子明显缺乏（<正常值的 1%） VIII (FVIII) 经常引起复发性自发性出血事件，导致显着的发病率和 HA 的常规治疗采用输注供体血浆 FVIII 冷沉淀产品。 病毒性疾病（包括艾滋病毒和丙型肝炎）的血液传播可能会使情况变得复杂。 重组 FVIII (rFVIII) 产品已在很大程度上取代了人源 FVIII 的使用（因为 rFVIII 然而，血浆 FVIII 在整个过程中仍然是 HA 的宝贵资源 FVIII 的预防性治疗需要每周静脉注射 FVIII 2-3 次。 不幸的是，在患者的一生中，反复静脉通路、依从性低、突破性的。 尽管使用 FVIII 预防，约 30% 的 HA 仍可能发生出血和关节损伤。 FVIII 替代产品的同种抗体抑制其恢复止血的能力。 这些患者的出血涉及使用昂贵的“旁路”药物治疗（即 FVIII 与 通过诱导对 FVIII 的免疫耐受已取得成功。 通过多次严格输注 FVIII（通常在预防性治疗的情况下），约 60% 的 HA 带有抑制性抗体 尽管 FVIII 抑制剂的治疗对于 HA 患者来说仍然是一个关键问题。 由于其单基因性质，HA 是基因替代疗法的理想候选者，具有潜在的 有前途的方法包括通过将人 FVIII 靶向表达到肝脏。 静脉输注裸DNA，生成新型腺相关病毒（AAV）载体 具有免疫原性较低的外壳蛋白，以及包含小活性形式的 FVIII 的载体（符合 AAV 的 4.4 kb 包装容量) 然而，这些策略排除了具有 1) 抑制性抗体的个体。 FVIII (约 30% PWHA)，2) 预先存在的 AAV 抗体（约 40% 人类）和 3) 慢性肝损伤。 为了解决这个具有相当临床意义的问题，我们提出了首次人体 I 期临床试验 采用利用慢病毒基因转移载体的造血干细胞 (HSC) 基因治疗策略 在巨核细胞特异性 ITGA2B 基因启动子的转录控制下编码人 FVIII 靶向巨核细胞中 FVIII 基因的表达，导致异位合成、储存和 因子 VIII 从活化血小板的 α 颗粒中精确地在血管损伤部位进行调节释放。 该提议得到了临床前研究的支持，该研究表明血小板 FVIII 安全有效地得到改善 在鼠和犬 HA 模型中实现止血，且不产生 FVIII 和抑制性抗体 即使小鼠体内预先存在 FVIII 抑制性抗体，该试验仍能发挥作用。 应该降低使用 FVIII 抑制性抗体的 PWHA 严重出血的风险。 采用因子旁路剂、耐受疗法和其他基因疗法的策略是不够的。 1