Optimization of a novel series of thiazolopyridines for the treatment of SMA

 描述(申请人提供)：脊髓性肌萎缩症(SMA)是一种神经退行性疾病，导致进行性肌肉无力。大约95%的SMA病例是由SMN1基因的两个拷贝丢失引起的。在人类中发现的SMN2基因与SMN1几乎完全相同，只表达少量的活性SMN蛋白。虽然SMN2不能完全补偿运动神经元中SMN1的丢失，但它为治疗干预提供了一个很好的靶点。来自内源性SMN2基因的功能性全长SMN蛋白的表达增加应该会减轻疾病的严重性。此前，我们开发了创新的报告细胞检测方法来诱导SMN的表达，来自这些检测的HIT化合物在SMN7小鼠模型中显示出积极的作用。最近，一种优化的类似物(LDN-2014)在非常严重的7和腹膜腔(IP)给药后的中度严重的2B/-模型中都显示了疗效，尽管LDN-2014没有适合进一步开发的药代动力学特性。我们现在已经应用同样的体外试验来筛选在LDDN设计和合成的新的化合物文库，并确定了可申请专利的线索；初步优化已经建立了易处理的SAR。此外，在这一新系列中发现了有效的化合物，在口服后具有良好的血浆和脑暴露。初步研究表明，新的一系列化合物具有与LDN-2014相似的作用机制，两者都在转录后发挥作用，并稳定SMN-蛋白。将这一新系列作为SMN2蛋白的激活剂进行优化是一种独特的方法，我们相信这将导致SMA的临床前开发候选药物。项目目标：目标1是对噻唑并吡啶系列进行药物化学优化，目的是在两种SMA小鼠模型上鉴定4-6种具有适合药理学评价的药代动力学性质的化合物。选择性增加SMN2-荧光素酶表达而不降低细胞活力的衍生物将被推进用于SMA来源的人成纤维细胞的二次筛选。将SMN蛋白水平提高1.5倍、EC50&lt；100 nm的分子将进入体外药物样属性分析(例如，溶解性、微粒体稳定性、渗透性)。这一迭代过程将继续下去，直到发现适合于小鼠口服PK实验的化合物。综上所述，体外和体内数据将被用来选择4-6种化合物在SMA小鼠模型中进行评估。目的2是在两种SMA小鼠模型中研究高级先导化合物的特征。从目标1产生的4-6个先导化合物将被推进到严重(LI)SMA小鼠模型中。在第二年，具有最佳整体特征的两个类似物将被选为较不严重的SMNRT模型的特征分析。我们相信，通过我们提议的严格的体外和体内评估产生的化合物将具有合适的质量，用于最终的临床前评估和进入临床研究。

 DESCRIPTION (provided by applicant): Spinal muscular atrophy (SMA) is a neurodegenerative disease that causes progressive muscle weakness. About 95% of SMA cases are caused by the loss of both copies of the SMN1 gene. The SMN2 gene found in humans is a nearly identical copy of SMN1 and expresses only a small amount of the active SMN protein. While SMN2 cannot fully compensate for the loss of SMN1 in motor neurons, it provides an excellent target for therapeutic intervention. Increased expression of functional full-length SMN protein from the endogenous SMN2 gene should lessen disease severity. Previously, we developed innovative reporter cell assays for inducers of SMN expression, and hit compounds from these assays demonstrated positive effects in the SMN7 mouse model. Very recently, an optimized analog (LDN-2014) demonstrated efficacy both in the very severe SMN7 and moderately severe 2B/- model following intraperitoneal (IP) dosing, although LDN-2014 did not have suitable pharmacokinetic properties for further development. We now have applied this same in vitro assay to screen a novel library of compounds designed and synthesized at the LDDN and identified patentable leads; preliminary optimization has established tractable SAR. Furthermore, potent compounds with good plasma and brain exposures following oral administration have been discovered from this new series. Preliminary investigations indicate that the new series of compounds has a similar mechanism of action as LDN-2014, both of which act post-transcriptionally and stabilize the SMN-protein. The optimization of this novel series as activators of SMN2 protein is a unique approach, which we believe will lead to pre-clinical development candidates for the treatment of SMA. Project Goals: Aim 1 is to conduct medicinal chemistry optimization of the thiazolopyridine series with the objective of identifying 4-6 compounds that have pharmacokinetic properties suitable for pharmacological evaluation in two mouse models of SMA. Derivatives that selectively increase SMN2-luciferase expression without decreasing cell viability will be advanced for secondary screening in SMA derived human fibroblasts. Molecules that increase SMN protein levels by >1.5 fold, and with EC50 < 100 nM, will be advanced into in vitro drug-like property assays (e.g., solubility, microsomal stability, permeability). This iterative process will continue until compounds suitable for mouse oral PK experiments are discovered. Taken together, the in vitro and in vivo data then will be used to select the 4-6 compounds to evaluate in mouse models of SMA. Aim 2 is the characterization of advanced lead compounds in two mouse models of SMA. The 4-6 leading compounds that emerge from Aim 1 will be advanced into the severe (Li) mouse model of SMA. In year 2, the two analogs with the best overall features will be selected for profiling in the less severe SMNRT model. We believe that compounds that emerge from the stringent in vitro and in vivo evaluation we are proposing will be of suitable quality for final pr-clinical evaluation and advancement into clinical studies.