Development of anti-LTBP4 as a biologic to treat Neuromuscular Diseases

项目摘要 神经肌肉疾病通常是可遗传的，并且通常导致力量的进行性丧失和无力， 站立、行走和呼吸。杜氏肌营养不良症（DMD）是一种遗传性神经肌肉疾病， 由于肌营养不良蛋白质的丢失，使得肌肉膜非常容易受到损伤。目前， 可用于纠正DMD中的神经肌肉缺陷或延迟疾病的治疗方法有限， 尽管一些治疗方法最近已被批准或正在进行临床试验，但它仍然存在进展。尽管如此 尽管这些治疗方法取得了成功，但它们只适用于一小部分患者，而且疗效有限。潜 TGF-β结合蛋白4（LTBP 4）被发现是肌营养不良症的遗传修饰剂， 无偏见的全基因组筛选。随后，它被证明在人类中具有类似的遗传修饰信号。 DMD患者。LTBP 4蛋白定位于肌纤维外部，在那里它结合并隔离所有三种形式 TGF-β，调节潜在的TGF-β释放和激活及其随后的病理级联反应， 下行信号。过度的TGF-β活化是许多形式的神经肌肉损伤中的病理学发现。 疾病，特别是DMD、肢带型肌营养不良症和先天性肌营养不良症。在 在肌营养不良症中，过量或过度活化的TGF-β与肌肉的纤维化浸润有关，并且受损 肌肉再生遗传数据用于鉴定LTBP 4的铰链区对潜伏性至关重要 TGF-β释放和活化。LTBP 4的铰链区可以被蛋白水解切割，并且这种切割 促进潜在TGF-β的释放，然后通过其他步骤完全激活。基因保护 小鼠中的LTBP 4形式对蛋白酶切割较不敏感，这与正常的 在肌营养不良症中，TGF-β处于过度活跃状态，并且这与延迟的营养不良进展相关。在 在人类中，LTBP 4的保护作用与三个独立的DMD队列中的更长的Amplitude相关。 我们设计了一种抗体策略来稳定LTBP 4铰链并限制潜在的TGF-β释放。证明 DMD的mdx小鼠模型中的概念数据表明， 区域可用于缓解疾病进展。抗LTBP 4铰链区抗体保护免受 LTBP 4裂解，减少纤维化形成，并增强肌肉损伤后的恢复。该提案概述了 用于治疗神经肌肉疾病的先导LTBP 4生物制剂的开发计划分为两部分 阶段。第1阶段的第一个目的是优化电极导线LTBP 4生物制剂，并评估短期内 优化电极导线的体内疗效。第一阶段的第二个目的是验证药效学生物标志物 测定。第二阶段的目标1将侧重于临床前研究和开始生产， 2将临床候选人推进到BioPharm早期开发和IND备案。

PROJECT SUMMARY Neuromuscular disorders are often heritable and typically result in progressive loss of strength and inability to stand, walk, and breathe. Duchenne Muscular Dystrophy (DMD) is a inherited neuromuscular disorder caused by the loss of dystrophin protein, which renders the muscle membrane highly susceptible to injury. Currently, there are limited therapies available to correct the neuromuscular defects in DMD or delay disease progression, although a number of treatments have been recently approved or are in clinical trials. Despite this success, these treatments are only available to small percentage of patients and have limited efficacy. Latent TGF-β Binding Protein 4 (LTBP4) was discovered as a genetic modifier of muscular dystrophy using an unbiased genomewide screen. It was subsequently shown to have a similar genetic modifying signal in human DMD patients. LTBP4 protein localizes to the myofiber exterior where it binds and sequesters all three forms of TGF-β, regulating latent TGF-β release and activation and its subsequent cascade of pathological downstream signaling. Excess TGF-β activation is a pathological finding in many forms of neuromuscular disease, especially DMD, the limb girdle muscular dystrophies and the congenital muscular dystrophies. In the muscular dystrophies, excess or hyper-activated TGF-β is linked to fibrotic infiltration of muscle and impaired muscle regeneration. The genetic data was used to identify the hinge region of LTBP4 as critical to latent TGF-β release and activation. LTBP4's hinge region can be proteolytically cleaved and this cleavage promotes release of latent TGF-β, which is then fully activated by additional steps. The genetically protective form of LTBP4 in mice is less susceptible to protease cleavage, correlating with a decrease of the normally hyperactive TGF-β state in muscular dystrophy, and this correlates with delayed dystrophy progression. In humans, the protective effect of LTBP4 correlated with longer ambulation in three independent DMD cohorts. We devised an antibody strategy to stabilizes the LTBP4 hinge and limit latent TGF-β release. Proof of concept data in the mdx mouse model of DMD demonstrates that an anti-LTBP4 antibody directed at the hinge region can be used to mitigate disease progression. Anti-LTBP4 hinge region antibodies protected against LTBP4 cleavage, reduced fibrosis formation, and enhanced recovery after muscle injury. This proposal outlines the developmental plan of a lead LTBP4 biologic for the treatment of neuromuscular disorders split into two phases. The first aim of phase 1 is designed to optimize the lead LTBP4 biologic and evaluate short-term in vivo efficacy of the optimized leads. The second aim of phase 1 is to validate pharmacodynamic biomarker assays. Aim 1 of the second phase will focus on pre-clinical studies and initiation of manufacturing, while aim 2 will progress the clinical candidate into BioPharm Early Development and IND filing.