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马西替尼治疗肌萎缩侧索硬化症(ALS):临床前概述

Masitinib for the treatment of amyotrophic lateral sclerosis (ALS): preclinical overview
课程网址: http://videolectures.net/encals2017_barbeito_masitinib_preclinica...  
主讲教师: Luis Barbeito
开课单位: 蒙得维的亚巴斯德学院
开课时间: 2017-07-21
课程语种: 英语
中文简介:
马西替尼是一种选择性口服酪氨酸激酶抑制剂,靶向CSF1R和c-Kit。马西替尼治疗肌萎缩侧索硬化症(ALS)的第3阶段研究(AB10015)的临床数据表明,在其主要终点(ALSFRS-R从基线检查到第48周的变化)的疾病进展具有临床意义。研究结果表明,在基线检查时ALSFRS-R进展<1.1分/月的ALS患者中,添加4.5 mg/kg/天的马西替尼作为利鲁唑的补充,产生了可接受的毒性。疾病的显著减缓表现为:•∆ALSFRS-R和ALSFRS-R斜率,表明功能丧失速度减慢治疗开始和结束之间经过的时间∆ALSFRS-R为九分(PFS),表明疾病进展延迟ALSAQ-40分,表明生活质量下降减少;和•FVC,这被认为是总体生存率的替代指标。AB10015研究的积极效益-风险平衡表明,马西替尼可以为这一难以治疗的人群提供重要的新治疗选择。这些积极的临床发现得到了同样令人信服的临床前数据的支持,显示马西替尼通过靶向异常小胶质细胞和调节神经炎症产生神经保护作用。在文献中,小胶质细胞的增殖和聚集(小胶质增生),特别是异常胶质细胞的出现,是ALS动物模型的主要神经病理学特征。这种疾病机制受CSF1/CSF1R信号通路的调控,使小胶质细胞成为马西替尼的可行靶点。我们之前报道过,在瘫痪发作后7天(治疗环境)开始对SOD1G93A大鼠进行马西替尼治疗,产生了强有力的保护作用,与对照组相比,瘫痪后存活时间显著延长(改善40%,p<0.001)。免疫组化数据还显示,马西替尼治疗:阻止小胶质细胞增殖、迁移和转化为异常胶质细胞;减少退化脊髓中异常胶质细胞的数量;改善小胶质细胞增生和运动神经元病理学;抑制小胶质细胞促炎表型的出现;抑制退行性脊髓沿线的小胶质细胞增生。紧急数据显示,马西替尼也能够在瘫痪发作后对SOD1G93A大鼠的周围神经系统产生保护作用。在退化的坐骨神经中观察到CSF1和IL-34的强烈上调,以及巨噬细胞和肥大细胞的高度浸润。Masitinib治疗可减少坐骨神经的病理变化,表达CSF1R的巨噬细胞和表达c-Kit的肥大细胞的炎性浸润显著减少。此外,在ALS大鼠模型中,masitinib可改善瘫痪进展期间的神经肌肉病理学,防止退化运动神经末梢周围的肥大细胞聚集,延迟终板失神经支配以及神经肌肉连接的病理重塑,突触周雪旺细胞和多支毛细血管网络。考虑到过去20年来ALS候选药物的持续失败,上述关于马西替尼在中枢和外周神经系统中作用机制的临床和临床前数据标志着真正的突破。
课程简介: Masitinib is a selective oral tyrosine kinase inhibitor targeting CSF1R and c-Kit. Clinical data from the phase 3 study (AB10015) of masitinib in amyotrophic lateral sclerosis (ALS) demonstrated a clinically meaningful retardation of disease progression on its primary endpoint (change from baseline to week 48 in ALSFRS-R). Findings showed that masitinib administered at 4.5 mg/kg/day as an add-on to riluzole generated a therapeutic benefit with acceptable toxicity in ALS patients experiencing ALSFRS-R progression of <1.1 points/month at baseline. Significant slowing of disease was evident in terms of: • ∆ALSFRS-R and ALSFRS-R slope, indicating a slowed loss of function; • Time elapsed between treatment initiation and ∆ALSFRS-R of nine points (PFS), indicating delayed disease progression; • ALSAQ-40 score, indicating reduced decline in quality-of-life; and • FVC, which is considered a surrogate measure of overall survival. The positive benefit–risk balance of study AB10015 signals that masitinib could provide an important new therapeutic option in this difficult to treat population. These positive clinical findings are supported by equally compelling preclinical data, showing masitinib to generate a neuroprotective effect through targeting aberrant microglial cells and regulating neuroinflammation. It is well-established in the literature that proliferation and accumulation of microglial cells (microgliosis), in particular the emergence of aberrant glial cells, is a major neuropathological feature for ALS animal models. This disease mechanism is regulated by the CSF1/CSF1R signaling pathway, making microglia a viable target for masitinib. We have previously reported that masitinib treatment of SOD1G93A rats, initiated 7 days after paralysis onset (therapeutic setting), generated a robust protective effect as evidenced by a significantly prolonged post-paralysis survival with respect to control (40% improvement, p<0.001). Immunohistochemistry data additionally showed that masitinib treatment: prevented microglia proliferation, migration and transformation into aberrant glial cells; reduced the number of aberrant glial cells in the degenerating spinal cord; improved microgliosis and motor neuron pathology; inhibited emergence of microglia proinflammatory phenotype; and inhibited microgliosis along the degenerating spinal cord. Emergent data show masitinib is also capable of producing protective effects in the peripheral nervous system of SOD1G93A rats after paralysis onset. Strong upregulation of CSF1 and IL-34 in the degenerating sciatic nerve was observed, as well as a high infiltration of macrophages and mast cells. Masitinib treatment resulted in reduced pathological changes in the sciatic nerve, with a sharp decrease of inflammatory infiltrates of CSF1R-expressing macrophages and c-Kit expressing mast cells. Moreover, masitinib was seen to ameliorate neuromuscular pathology during paralysis progression in the ALS rat model, preventing mast cell accumulation around degenerative motor nerve endings, delaying endplate denervation as well as the pathological remodeling of neuromuscular junctions, perisynaptic Schwann cells and mu1scular capillary networks. Considering the persistent failure of candidate ALS drugs over the past 20 years, the abovementioned clinical and preclinical data for masitinib mechanisms of action in both the central and peripheral nervous system, signal a genuine breakthrough.
关 键 词: 马西替尼; 肌萎缩侧索硬化症; 调节神经炎症
课程来源: 视频讲座网
数据采集: 2021-12-11:zkj
最后编审: 2021-12-11:zkj
阅读次数: 276