Defining the therapeutic efficacy, tolerogenic potential, and genotoxicity of liver-targeted AAV gene therapy for hemophilia A

定义肝脏靶向 AAV 基因疗法治疗血友病 A 的疗效、耐受潜力和遗传毒性

• 批准号: 10704568
• 负责人: Graca Duarte Almeida-Porada
• 金额: $ 67.39万
• 依托单位: WAKE FOREST UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-15 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10704568
• 关键词: Address; Adult; Animal Model; Biological; Birth; Blood Coagulation Disorders; Blood Coagulation Factor; Capsid; Cell Proliferation; Cells; Clinical; Clinical Trials; Clonal Expansion; Cross Presentation; Data; Dose; Early treatment; Enzyme-Linked Immunosorbent Assay; Event; Exhibits; Exposure to; F8 gene; Fetal Development; Fetal Sheep; Fetus; Fibrosis; Gene Transfer; Gene therapy trial; Genetic Diseases; Genome; Genomics; Goals; Hemophilia A; Hemorrhage; Hepatocyte; Hepatotoxicity; Human; Immune; Immune Tolerance; Immune response; Immunity; Immunologics; Incidence; Inflammatory Response; Inherited; Innate Immune Response; Intrauterine Blood Transfusion; Life; Liver; Location; Mediating; Neonatal; Newborn Infant; Onset of illness; Organ; Patients; Plasma; Primary carcinoma of the liver cells; Production; Proteins; Recording of previous events; Risk; Safety; Serotyping; Sheep; System; Testing; Therapeutic; Thymic epithelial cell; Tissues; Transgenes; Treatment Efficacy; adeno-associated viral vector; biological adaptation to stress; cell type; clinically relevant; cytokine; fetal; gene therapy; gene therapy clinical trial; genomic locus; genotoxicity; in utero; in utero transplantation; in vivo; inhibitor; liver function; liver inflammation; manufacturing run; minimal risk; neonatal period; neonate; neutralizing antibody; participant enrollment; postnatal; pre-clinical; prenatal; prenatal exposure; prevent; safety testing; tissue tropism; transgene expression; tumorigenesis; vector; vector genome; vector induced

PROJECT SUMMARY: Gene therapy (GT) for the hemophilias is poised to fulfill the promise of a safe, affordable, lifelong correction following a single treatment. Yet clinical trials employing AAV vectors to treat adult hemophilia A (HA) patients have underscored the risk of hepatoxicity and genotoxicity in adult patients receiving GT. In addition, the use of AAV-based GT is prevented by pre-existing AAV immunity in a high percentage of patients. While FVIII inhibitors have not yet been seen in GT trials, inhibitors usually appear within the first 50 exposure days to FVIII, and since all enrolled patients were selected based upon an inhibitor-free clinical history, it is likely that the patients were not “inhibitor-prone”, leaving unanswered the critical question of whether GT will avoid inhibitor induction. GT to treat HA at birth provides the advantage of correcting bleeding events sooner, but whether neonatal GT would avoid FVIII inhibitor induction and hepatic inflammation is, at present, unknown. Recent studies have shown a 59% incidence of neutralizing antibodies to AAV at birth. Thus, treatment during the neonatal period will likely be hampered by anti-AAV immunity. One approach that could circumvent both AAV- and FVIII-related immune hurdles while enabling correction prior to disease onset is in utero GT (IUGT). Using the same preclinical animal model (sheep) used to delineate conditions to cure SCID patients prenatally, we showed that the highly proliferative state and relative immune-immaturity of the fetus can be exploited to achieve clinically relevant levels of gene transfer to multiple tissues and induce durable tolerance to vector- encoded proteins. Besides its inherent advantages as a GT recipient, its rapid cellular turnover makes the fetus a highly sensitive system in which to define the potential genotoxicity and risk of tumorigenesis following AAV GT. This rapid cellular proliferation also provides a rigorous testbed to define the incidence and locations of AAV genomic integration, determine the duration of AAV persistence, and identify the optimal target cell(s) within the liver to achieve long-term expression of a fVIII transgene and resultant therapeutic benefit. The overall goal of this proposal is to use fetal sheep to address critical unanswered biological and safety questions that plague liver-targeted AAV-based GT for HA and test the hypothesis that performing AAV-based IUGT will overcome the immune hurdles inherent to postnatal GT, transduce sufficient numbers of the appropriate hepatic cells to mediate long-term therapeutic plasma FVIII levels, and induce durable tolerance to FVIII. We propose 3 Aims: i) Define the in vivo tissue tropism of two AAV serotypes in use in clinical trials for HA (AAV5 and AAV3B) following administration into fetal and neonatal recipients; ii) Define the impact of fVIII-encoding AAV transduction on fetal vs. neonatal liver function; and iii) Determine the duration of fVIII-AAV persistence and fVIII transgene expression, and whether durable immune tolerance is induced to FVIII and/or AAV following in utero vs. neonatal GT. We hope that these studies will elucidate whether IUGT or neonatal GT for HA will be safe, and whether or not the therapy will be long-lasting, prevent breakthrough bleeds, and avoid FVIII immune responses.

项目摘要：血友病的基因疗法（GT）被毒死，以实现安全，负担得起的承诺 单次治疗后的终身纠正。然而，采用AAV载体治疗成人血友病的临床试验 A（HA）患者强调了接受GT的成年患者的肝毒性和遗传毒性的风险。在 此外，通过在高百分比的患者中预先存在AAV免疫来预防基于AAV的GT的使用。 尽管在GT试验中尚未看到FVIII抑制剂，但抑制剂通常出现在前50个暴露范围内 FVIII的天数，并且由于所有注册的患者均根据无抑制剂临床病史选择，因此很可能 患者不是“容易抑制剂” 抑制剂诱导。 GT在出生时治疗HA提供了更快纠正出血事件的优势，但是 目前，新生儿GT是否会避免FVIII抑制剂诱导和肝脏注射是未知的。 最近的研究表明，出生时中和AAV抗体的发生率为59％。那期间的治疗 抗AAV免疫学可能会阻碍新生儿时期。一种可以绕过两者的方法 AAV和FVIII相关的免疫螺旋螺旋体在疾病发作之前实现校正时，在子宫内（IUGT）。 使用相同的临床前动物模型（绵羊）用于描绘疾病以在产前治愈SCID患者， 我们表明，可以探索胎儿的高度增殖状态和相对免疫不符。 实现临床上相关的基因转移到多个时序的水平，并诱导对载体的持久耐受性 - 编码的蛋白质。除了其作为GT接收者的固有优势外，其快速的蜂窝周转率使得胎儿 一个高度敏感的系统，用于定义AAV后肿瘤发生潜在的遗传毒性和风险 GT。这种快速的细胞增殖还提供了严格的测试床，以定义AAV的事件和位置 基因组整合，确定AAV持久性的持续时间，并确定最佳目标细胞 肝脏的长期表达FVIII转化和由此产生的治疗益处。总体目标 该建议是使用胎儿绵羊解决瘟疫的关键未解决的生物学和安全问题 基于肝脏的AAV GT用于HA并检验以下假设，即执行基于AAV的IUGT将克服 免疫障碍是产后GT固有的，将足够数量的适当肝细胞转导 介导长期治疗性血浆FVIII水平，并诱导FVIII持久的耐受性。我们提出3个目标：i） 定义在HA（AAV5和AAV3B）中使用两种AAV血清型的体内组织向潮流 给予胎儿和新生儿接受者； ii）定义FVIII编码AAV翻译对胎儿的影响 与新生儿肝功能； iii）确定FVIII-AAV持久性和FVIII变换的持续时间 表达，以及是否诱导持久的免疫耐受性诱导为FVIII和/或AAV。 GT。我们希望这些研究能阐明IUGT或NEONATAL GT HA是否安全，以及是否或 疗法不是持久的，可以防止突破出血，并避免FVIII免疫反应。