Development of rAAV-mediated gene therapy for a severe paediatric metabolic liver disease: Ornithine Transcarbamylase deficiency.

开发 rAAV 介导的基因疗法治疗严重的儿科代谢性肝病：鸟氨酸转氨甲酰酶缺乏症。

• 批准号: MR/N019075/1
• 负责人: Paul Gissen
• 金额: $ 222.24万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FN019075%2F1
• 关键词: Development; rAAV; mediated; gene; therapy

The urea cycle is an essential pathway in the liver which is necessary for the detoxification of ammonia, produced by the breakdown of proteins. Ammonia is highly neurotoxic, and defects in any of the urea cycle enzymes leads to high rates of mortality and morbidity. Ornithine transcarbamylase (OTC) deficiency is the most common of the urea cycle defects. In the most severe forms of the disease, symptoms present early in the newborn period progressing to coma and death if untreated. Patients are managed by pharmacological and dietary intervention but ultimately require a liver transplant for long-term survival. However, liver transplantation is associated with its own risks - mortality, morbidity and life-long need for immunosuppression.Gene therapy offers an attractive alternative to liver transplantation, as the patient's own cells are repaired by transfer of a functional gene. Adeno-associated viruses (AAV) are emerging as a highly effective gene delivery system, and the ability to alter the outer coat (capsid) of the virus allows a variety of cells to be targeted. AAV8 is currently yielding promising results in the liver in a clinical trial for Haemophilia B (Factor IX deficiency), led by UCL. While exciting, this success is made possible by the low number of liver cells that need to be genetically repaired in this condition, as the Factor IX protein is released (secreted) into the bloodstream with as little as 1-2% of normal levels providing therapeutic benefit. In many metabolic conditions involving the liver, such as OTC deficiency, where the gene product is not secreted, a much higher proportion of cells must be modified for clinical success. Prof. Alexander has successfully cured OTC-deficient mice using an AAV8-based gene therapy approach, however, AAV8 is far less effective for gene delivery to human liver cells. An exciting collaboration with colleagues at Stanford University has led to the development of a novel AAV, referred to as LK03, which targets human liver cells with a much higher efficiency that AAV8 (12 times). We therefore propose a first-in-man use of an AAV gene delivery system based on AAV/LK03 for the treatment of OTC deficiency in paediatric patients.This application describes pivotal preclinical studies required to support authorisation of a phase I/II UK-based AAV/LK03-mediated clinical trial for OTC deficiency, and builds on already funded studies seeking to refine AAV/LK03 for clinical trial use. The proposed preclinical studies include immunological investigation of the target paediatric population, quality control tests (potency, safety and purity) on clinical-grade reagent, and toxicology and biodistribution studies in non-human primates. Non-human primates are the chosen animal model for these studies as the gene therapy delivery system is highly specific for human liver cells, with very little ability to function in mouse liver cells.Initially, a survey of the immunological status (seroprevalence) will be carried out on the target paediatric population. The presence of antibodies (humoral immunity) to AAV/LK03 can impede the effectiveness of the gene delivery. Given that previous surveys have shown that humoral immunity to AAV does not generally develop before the age of two, and the majority of trial participants will be younger than this, this is unlikely to be a significant problem. The gene therapy reagent will be produced in the UCL Vector Core Facility and subjected to standard safety, purity and sterility testing. The reagent will then be tested in Cynologmus macaques for toxicology and biodistribution. At the conclusion of the pre-clinical testing, the results will be presented to the Medicines and Healthcare Products Regulatory Agency (MHRA) in the form of an Investigational Medicinal Product Dossier (IMPD) to request Clinical Trial Authorisation. These results will also support an Orphan Designation application of the gene therapy reagent at the European Medicine Agency.

尿素循环是肝脏中解毒所必需的基本途径，氨是由蛋白质分解产生的。氨具有高度的神经毒性，任何尿素循环酶的缺陷都会导致高死亡率和发病率。鸟氨酸氨基转移酶(OTC)缺乏症是最常见的尿素循环缺陷。在最严重的疾病形式中，在新生儿期早期出现的症状会发展到昏迷，如果不治疗就会死亡。患者通过药物和饮食干预进行管理，但最终需要肝脏移植才能长期生存。然而，肝移植有其自身的风险--死亡率、发病率和终身需要免疫抑制。基因治疗为肝移植提供了一种有吸引力的替代方案，因为患者自身的细胞是通过转移功能基因来修复的。腺相关病毒(AAV)是一种高效的基因传递系统，改变病毒外壳(衣壳)的能力使各种细胞成为靶点。AAV8目前在UCL领导的治疗血友病B(因子IX缺乏症)的临床试验中取得了令人振奋的结果。虽然令人兴奋，但这种成功是因为在这种情况下需要遗传修复的肝细胞数量很少，因为因子IX蛋白被释放(分泌)到血液中，只有正常水平的1-2%提供治疗益处。在许多涉及肝脏的代谢情况下，例如OTC缺乏症，基因产物不能分泌，必须对更高比例的细胞进行修饰才能在临床上取得成功。Alexander教授已经成功地使用基于AAV8的基因治疗方法治愈了OTC缺陷小鼠，然而，AAV8在将基因输送到人类肝细胞方面的效率要低得多。与斯坦福大学的同事们令人兴奋的合作导致了一种被称为LK03的新型AAV的开发，它针对人类肝细胞的效率比AAV8(12倍)高得多。因此，我们建议首次将基于AAV/LK03的AAV基因递送系统用于治疗儿科OTC缺乏症。这一应用描述了支持基于英国的AAV/LK03介导的OTC缺乏症I/II期临床试验授权所需的关键临床前研究，并建立在已有资金研究的基础上，寻求完善AAV/LK03用于临床试验。拟议的临床前研究包括目标儿科人群的免疫学调查，临床级试剂的质量控制测试(效力、安全性和纯度)，以及在非人类灵长类动物中的毒理学和生物分布研究。非人灵长类动物是这些研究的动物模型，因为基因治疗传递系统对人类肝细胞高度特异，在小鼠肝细胞中几乎没有发挥作用的能力。最初，将对目标儿科人群进行免疫学状态(血清阳性率)的调查。AAV/LK03抗体(体液免疫)的存在会阻碍基因传递的有效性。鉴于之前的调查显示，对AAV的体液免疫力一般不会在两岁之前形成，而且大多数试验参与者将比这更年轻，这不太可能成为一个重大问题。基因治疗试剂将在UCL载体核心设施中生产，并接受标准的安全性、纯度和无菌测试。然后，该试剂将在食蟹猴身上进行毒理学和生物分布测试。在临床前测试结束时，结果将以研究药品档案(IMPD)的形式提交给药品和保健产品监管机构(MHRA)，以请求临床试验授权。这些结果也将支持欧洲医药机构对基因治疗试剂的孤儿指定申请。

项目成果

Three-Country Snapshot of Ornithine Transcarbamylase Deficiency.

• DOI: 10.3390/life12111721
• 发表时间: 2022-10-27
• 期刊: Life (Basel, Switzerland)
• 作者: Seker Yilmaz B;Baruteau J;Arslan N;Aydin HI;Barth M;Bozaci AE;Brassier A;Canda E;Cano A;Chronopoulou E;Connolly GM;Damaj L;Dawson C;Dobbelaere D;Douillard C;Eminoglu FT;Erdol S;Ersoy M;Fang S;Feillet F;Gokcay G;Goksoy E;Gorce M;Inci A;Kadioglu B;Kardas F;Kasapkara CS;Kilic Yildirim G;Kor D;Kose M;Marelli C;Mundy H;O'Sullivan S;Ozturk Hismi B;Ramachandran R;Roubertie A;Sanlilar M;Schiff M;Sreekantam S;Stepien KM;Uzun Unal O;Yildiz Y;Zubarioglu T;Gissen P
• 通讯作者: Gissen P

Age-Related Seroprevalence of Antibodies Against AAV-LK03 in a UK Population Cohort.

• DOI: 10.1089/hum.2018.098
• 发表时间: 2019-01
• 期刊: Human gene therapy
• 影响因子: 4.2
• 作者: Perocheau DP;Cunningham S;Lee J;Antinao Diaz J;Waddington SN;Gilmour K;Eaglestone S;Lisowski L;Thrasher AJ;Alexander IE;Gissen P;Baruteau J
• 通讯作者: Baruteau J

Recapitulation of Skewed X-Inactivation in Female Ornithine Transcarbamylase-Deficient Primary Human Hepatocytes in the FRG Mouse: A Novel System for Developing Epigenetic Therapies.

FRG 小鼠中雌性鸟氨酸转氨甲酰酶缺陷的原代人肝细胞中偏向 X 失活的重述：用于开发表观遗传疗法的新系统。

• DOI: 10.1089/hum.2023.011
• 发表时间: 2023
• 期刊: Human gene therapy
• 影响因子: 4.2
• 作者: Cunningham SC

Gene therapy for monogenic liver diseases: clinical successes, current challenges and future prospects.

• DOI: 10.1007/s10545-017-0053-3
• 发表时间: 2017-07
• 期刊: Journal of inherited metabolic disease
• 影响因子: 4.2
• 作者: Baruteau J;Waddington SN;Alexander IE;Gissen P
• 通讯作者: Gissen P

Urea Cycle Related Amino Acids Measured in Dried Bloodspots Enable Long-Term In Vivo Monitoring and Therapeutic Adjustment.

在干血斑中测量尿素循环相关氨基酸可以实现长期体内监测和治疗调整。

• DOI: 10.3390/metabo9110275
• 发表时间: 2019
• 期刊: Metabolites
• 影响因子: 4.1
• 作者: Baruteau J