Development of a novel accurate therapy for multiple sclerosis

项目摘要 多发性硬化症（MS）是成年早期最常见的神经系统疾病， 导致中枢神经系统脱髓鞘和神经元损伤的自身免疫机制， 导致进行性神经功能障碍。到目前为止，还没有治愈这种毁灭性疾病的方法， 目前可用的治疗集中在预防未来的免疫攻击，主要是通过抑制 这会对免疫系统产生不良影响，通常是严重的或致命的。因此，有一个明确的 开发有效且耐受性良好的治疗以阻止MS发展的未满足需求。减少 副作用，MS药物应避免免疫抑制机制，并应针对特定的 病因学这一直是具有挑战性的，因为MS有多种病因（>500个基因被确定为风险因素 对于MS迄今为止），并且这些病因学的分子机制还没有很好地理解。 为了解决这一未满足的需求，我们开发了一种个性化的治疗方法，可以纠正MS的特定病因 由可溶性白细胞介素7受体（sIL 7R）水平升高引起， 通过在前mRNA剪接期间异常排除IL 7R外显子6来检测IL 7R水平。提示sIL 7R参与了 在MS和自身免疫性中，它已被证明：（i）被MS风险变体上调，（ii）加剧MS和自身免疫性的严重性。 在MS的实验性自身免疫性脑脊髓炎（EAE）小鼠模型中， 在几种自身免疫性疾病患者中升高，包括MS、1型糖尿病、风湿性关节炎 和系统性红斑狼疮总的来说，这些发现支持了这样一个科学前提： sIL 7R在MS和可能的sIL 7R上调的其它自身免疫性疾病中是治疗性的。 考虑到sIL 7R是通过从IL 7R RNA中排除外显子6而产生的，我们开发了反义IL 7R， 寡核苷酸（ASO），其促进包含该关键外显子并降低sIL 7R表达（抗sIL 7R ASO）。通过纠正MS的这种病因学，预测抗sIL 7R ASO可有效预防MS复发， 减少与免疫抑制相关的副作用。在第一阶段研究中，我们优化了这些ASO 在体外以最小的细胞毒性有效地减少人原代T细胞中的sIL 7R分泌。体内功效 抗sIL 7R ASO的研究限于非人灵长类动物（NHP），因为IL 7R外显子的选择性剪接 6仅在灵长类动物中观察到，其中猕猴是理想的模型，因为它们表达的sIL 7R水平 等同于在患有该病因的MS患者中观察到的那些。 本阶段旨在推进抗sIL 7R ASO作为MS潜在治疗药物的临床前开发 我们将评估铅抗sIL 7R ASO在患者中的生物分布、安全性和治疗疗效。 食蟹猴（Macaca fascicularis）中高度相关EAE模型。这项关键性的研究将使 为随后的IND使能研究和临床试验奠定基础，如果成功，有可能提供 为多发性硬化症提供一流的精准医疗

PROJECT SUMMARY Multiple Sclerosis (MS) is the most common neurological disease of early adulthood and is mediated by autoimmune mechanisms that lead to demyelination and neuronal damage in the central nervous system, resulting in progressive neurological dysfunction. Up to date, there is no cure for this devastating disease and current available treatments focus on preventing future immunological attacks, primarily by suppressing the immune system, and this has adverse side effects that are often severe or fatal. Accordingly, there is a clear unmet need for the development of effective and well-tolerated therapies to arrest MS development. To reduce side effects, MS drugs should avoid immunosuppressive mechanisms and should be targeted to specific etiologies. This has been challenging because MS has multiple etiologies (>500 genes identified as risk factors for MS so far) and the molecular mechanisms underlying these etiologies are not well understood. Addressing this unmet need, we developed a personalized therapy that corrects a specific etiology of MS caused by elevated levels of the soluble form of the Interleukin 7 Receptor (sIL7R), which rises to pathogenic levels by aberrant exclusion of IL7R exon 6 during pre-mRNA splicing. Implicating sIL7R in the pathogenesis of MS and autoimmunity, it has been shown to: (i) be up-regulated by MS risk variants, (ii) exacerbate the severity of the disease in the Experimental Autoimmune Encephalomyelitis (EAE) mouse model of MS, and (iii) be elevated in patients from several autoimmune diseases, including MS, Type 1 diabetes, Rheumatoid arthritis and Systemic lupus erythematosus. Collectively, these findings support the scientific premise that a reduction in sIL7R would be therapeutic in MS and perhaps other autoimmune disorders where sIL7R is up-regulated. Given that sIL7R is generated by exclusion of exon 6 from IL7R RNAs, we developed antisense oligonucleotides (ASOs) that promote inclusion of this critical exon and reduce sIL7R expression (anti-sIL7R ASOs). By correcting this etiology of MS, anti-sIL7R ASOs are predicted to effectively prevent MS relapses while reducing side effects associated with immunosuppression. In our Phase I research, we optimized these ASOs ex vivo to efficiently reduce sIL7R secretion in human primary T cells with minimal cellular toxicity. In vivo efficacy studies of anti-sIL7R ASOs are limited to nonhuman primates (NHPs) because alternative splicing of IL7R exon 6 is observed exclusively in primates, of which macaques are the ideal model since they express sIL7R at levels equal to those observed in MS patients that suffer from this etiology. To advance pre-clinical development of anti-sIL7R ASOs as potential therapeutic drugs for MS, in this Phase II proposal we will assess the biodistribution, safety and therapeutic efficacy of lead anti-sIL7R ASOs in the highly relevant EAE model in cynomolgus macaques (Macaca fascicularis). This pivotal study will set the foundation for ensuing IND-enabling studies and clinical trials, and if successful, have the potential to provide a first-in-class precision medicine for MS.