Pre-clinical development of SPY-DYS45-55, a CRISPR/Cas9 platform for Duchenne muscular dystrophy

Myogene Bio是一家初创公司，致力于开发用于肌肉的尖端基因疗法 疾病。在这项提案中，该公司将推进我们潜在的治疗药物的开发， Duchenne肌营养不良症CRISPR/Cas9基因编辑平台SPY-DYS45-55 与加州大学洛杉矶分校的研究伙伴合作。杜兴是一种毁灭性的肌肉消耗 由DMD基因的框架外突变引起的无法治愈的疾病。SPY-DYS45-55 删除DMD中的突变热点以恢复一半Duchenne的读框 患者通过产生框内外显子45-55缺失。此删除与一个非常 人类Becker肌营养不良症患者的轻度表型。基因编辑的系统性传递 加强平台力量是一项重大挑战。重组腺相关蛋白的某些血清型 病毒(AAV)对骨骼肌和心脏有趋向性。然而，免疫力 对病毒的反应禁止重复接种AAV。此外，预先存在的 在一些个体中(预计高达70%的成年人存在)免疫，使他们的 是否有资格享受这一待遇。这项快速通道提案的目标是设计出 克服这些挑战的战略。在第一阶段，我们将确定一个最佳方案 免疫抑制方案，允许AAV的再治疗，以提高疗效和 SPY-DYS45-55的适用性。在第二阶段，我们将评估长期的功能效益， AAV-SPY-DYS45-55单次或多次注射的毒性和靶外活性 含有突变的人类DMD基因的小鼠模型。最终，这些研究将产生 将SPY-DYS45-55翻译为Duchenne肌肉型患者所需的初步临床前数据 营养不良。

MyoGene Bio is a startup dedicated to developing cutting edge genetic therapies for muscle diseases. In this proposal, the company will advance development of our potential therapeutic, SPY-DYS45-55, a CRISPR/Cas9 gene editing platform for Duchenne muscular dystrophy (DMD) in conjunction with research partners at UCLA. Duchenne is a devastating muscle wasting disorder with no cure that is caused by out-of-frame mutations in the DMD gene. SPY-DYS45-55 removes a mutational hotspot in DMD to restore the reading frame for half of all Duchenne patients by generating an in-frame exon 45-55 deletion. This deletion is associated with a very mild phenotype in human Becker muscular dystrophy patients. Systemic delivery of gene editing platforms to muscle represents a significant challenge. Certain serotypes of recombinant adenoassociated virus (AAV) have tropism to skeletal muscle and heart. However, the immune response to the virus prohibits repeated administration of AAV. Furthermore, pre-existing immunity in some individuals (anticipated to be present in up to 70% of adults), precludes their eligibility to take advantage of this treatment. The goal of this Fast Track proposal is to devise strategies to overcome these challenges. In Phase I, we will determine an optimal immunosuppression regimen that allows redosing of AAV in order to improve the efficacy and applicability of SPY-DYS45-55. In Phase II, we will assess the long-term functional benefit, toxicity, and off-target activity from single or multiple injections of AAV-SPY-DYS45-55 in our novel mouse model containing a mutated human DMD gene. Ultimately, these studies will generate the initial pre-clinical data needed to translate SPY-DYS45-55 to patients with Duchenne muscular dystrophy.