Pediatric toxicity and efficacy in long-term systemic treatment with anti-sense

描述（由申请人提供）：杜氏肌营养不良症是最常见的单基因儿科先天性缺陷，影响全世界每3,500名活产男性中的一名。DIVID最有希望的分子治疗方法是全身递送反义寡核苷酸（AO），其中药物改变mRNA剪接，并将框外丧失功能的转录物转化为能够产生半功能（贝克尔样）的框内转录物。 抗肌萎缩蛋白。在Duchenne营养不良的大型动物（狗）模型中，我们已经表明静脉内（iV）递送高浓度的 剂量的吗啉代AO能够将抗肌萎缩蛋白的蛋白质产量挽救至野生型水平的约20%，并引起多个功能、组织学和成像结果测量的稳定或改善（Yokota等人，2009）。使用针对外显子51的吗啉代AO的初始人类临床试验已经表明，直接肌内注射和IV施用都可以导致肌营养不良蛋白的从头产生。然而，预计可能需要20 mg/kg - 100 mg/kg的重复剂量才能维持疗效。由申请人申办的小鼠和非人灵长类动物GLP毒性研究表明，高剂量每周IV注射可导致药物在肾近端小管细胞中蓄积。这种累积在给药终止后消退，并且肾脏损伤的标准标志物没有升高。然而，DIVID患者的给药将需要是终身的，并且尚未优化给药方案或药物浓度以平衡肌肉与肾脏累积的功效。在这里，我们汇集了一个跨学科的团队来定义吗啉给药的治疗窗口。项目1与正在进行的剂量范围临床试验合作，通过尿液生物标志物和脱落的肾细胞监测肾毒性。项目2定义了AO浓度和给药方案对药物在肾小管细胞中蓄积的影响，还进行了生物标志物发现计划，以定义吗啉相关细胞损伤的敏感和可靠的尿液生物标志物。项目3使用已建立的鼠药物测试核心，定义了能够在肌营养不良症小鼠模型中提供持续临床疗效的最佳给药方案。肾脏毒理学评估核心支持这些项目。

DESCRIPTION (provided by applicant): Duchenne muscular dystrophy is the most common monogenic pediatric inborn error, affecting one in 3,500 live born males world-wide. The most promising molecular therapeutic approach for DIVID is systemic delivery of anti-sense oligonucleotides (AOs), where the drugs alter mRNA splicing, and converting out-of-frame loss-off function transcripts to in-frame transcripts capable of producing semi-functional (Becker-like) dystrophin. In the large animai (dog) model of Duchenne dystrophy, we have shown that intravenous (iV) delivery of high dose morpholino AOs is able to rescue dystrophin protein production to about 20% of wild-type levels, and cause stabilization or improvement of multiple functional, histological, and imaging outcome measures (Yokota et al. 2009). Initial human clinical trials using morpholino AO directed at exon 51 have shown that both direct intramuscular injection and IV administration can result in de novo dystrophin production. However, it is anticipated that repeated doses of 20 mg/kg - 100 mg/kg are likely required for sustained efficacy. GLP toxicity studies in mice and non-human primates, sponsored by the applicants, have shown that high dose weekly IV injections can lead to accumulation of drug in kidney proximal tubule cells. This accumulation resolved after termination of dosing, and there were no elevation of standard markers of kidney damage. However, dosing of DIVID patients will need to be life-long, and there has been no optimization of dosing schedules or drug concentrations that balance efficacy in muscle vs. kidney accumulation. Here, we bring together an interdisciplinary team to define the therapeutic window of morpholino dosing. Project 1 collaborates with an ongoing dose-ranging clinical trial to monitor kidney toxicity through urine biomarkers and shed renal cells. Project 2 defines the effects of AO concentrations, and dosing regimen on drug accumulation in kidney tubule cells, and also carries out a biomarker discovery program to define sensitive and reliable urine biomarkers for morpholino-associated cell damage. Project 3 defines the optimal dosing regimen able to provide sustained clinical efficacy in the mouse model of muscular dystrophy, using an established murine drug-testing core. A kidney toxicology assessment core supports these projects.