In vivo proof of efficacy studies for a novel glucosylceramide synthase inhibitor

描述（由申请方提供）：已对超过75种溶酶体蛋白进行了表征，其中42种蛋白的基因突变导致临床上独特的溶酶体贮积病。在这些疾病中，14例是鞘脂分解受损的结果，8例是鞘糖脂降解受损所致。治疗这些疾病的传统方法是通过使用甘露糖或甘露糖-6-磷酸封端的重组蛋白作为酶替代疗法的基础。另一种方法，现在临床证明用于治疗1型戈谢病，是使用合成抑制疗法。通过靶向鞘糖脂合成中的第一个合成步骤， 葡糖神经酰胺合酶，有效的小分子抑制剂被设计为用于治疗1型戈谢病和法布里病的高活性先导化合物。该系列中的一种化合物，酒石酸依格列他，已在II期试验中证明与伊米苷酶一样有效，目前是两项I型戈谢病III期研究的基础。由于酒石酸依格列他不能穿过血脑屏障，因此不适用于治疗累及CNS的几种鞘糖脂过多症，包括2型和3型戈谢病、早发性和迟发性泰-萨克斯病和GM 1神经节苷脂沉积症。利用先前R21奖项的资助，申请人利用先前定义的酒石酸依格列他药效团，对缺乏多药耐药转运蛋白MDR 1识别的葡萄糖神经酰胺合酶抑制剂进行了基于性质的设计。考虑到构象迁移率和拓扑极性表面积，确定了eliglustat的类似物，其在低纳摩尔范围内保留了对葡糖神经酰胺合酶的活性，在两项体外试验中缺乏MDR 1的识别，并显示短期给药可降低野生型小鼠的脑葡糖神经酰胺水平。我们现在建议在合适的3型戈谢病小鼠模型中研究该化合物2-（2，3-二氢-1H-茚-2-基）-N-（（1 R，2 R）-1-（2，3-二氢苯并[B][1，4]二恶英-6-基）-1-羟基-3-（吡咯烷-1-基）丙-2-基）乙酰胺（CCG-203586），以确定其是否是临床开发的适当候选药物。以下假设有待检验。CCG-203586将延迟或预防神经病戈谢小鼠模型中神经功能恶化和死亡的发生。该项目的具体目标包括：1.确定CCG-203586口服给药的最佳处方。 2.建立血液和组织（包括脑）中CCG-203586的测定方法。 3.在野生型小鼠中进行药代动力学研究，以确定CCG-203586的生物利用度、半衰期、分布、代谢和排泄。 4.用CCG-203586经口或胃肠外给药治疗神经病戈谢小鼠，以确定其在降低外周组织和脑葡糖神经酰胺蓄积、延迟或预防死亡、预防脑组织病理学变化以及脑和外周组织炎症变化方面的疗效。

DESCRIPTION (provided by applicant): Greater than 75 lysosomal proteins have been characterized, and genetic mutations in 42 of these proteins result in clinically unique lysosomal storage diseases. Of these disorders, 14 are the result of impaired catabolism of sphingolipids and 8 are due to the impaired degradation of glycosphingolipids. The traditional approach for treating these disorders has been through the use of mannose or mannose-6-phosphate terminated recombinant proteins as the basis for enzyme replacement therapy. An alternative approach, now clinically proven for the treatment of type 1 Gaucher disease, is the use of synthesis inhibition therapy. By targeting the first synthetic step in glycosphingolipid synthesis, glucosylceramide synthase, potent small molecule inhibitors were designed as highly active lead compounds for the treatment of Gaucher type 1 and Fabry disease. One compound in this series, eliglustat tartrate, has been demonstrated to be as efficacious as imiglucerase in phase 2 trials and is currently the basis for two phase 3 studies for type 1 Gaucher disease. Because eliglustat tartrate does not cross the blood brain barrier, it is unsuitable for the treatment of several glycosphingolipidoses with CNS involvement that include types 2 and 3 Gaucher disease, early and late onset Tay-Sachs disease, and GM1 gangliosidosis. With funding from a prior R21 award, the applicants undertook the property-based design of inhibitors of glucosylceramide synthase that lack recognition by the multidrug resistance transporter MDR1 utilizing the previously defined pharmacophore for eliglustat tartrate. Using considerations of conformational mobility and topological polar surface area, an analog of eliglustat was identified that retained activity against glucosylceramide synthase in the low nanomolar range, lacked recognition by MDR1 in two in vitro assays, and was shown to lower brain glucosylceramide levels in wild type mice with short term dosing. We now propose to study this compound, 2-(2,3-dihydro-1H-inden-2-yl)-N-((1R,2R)-1-(2,3- dihydrobenzo[b][1,4]dioxin-6-yl)-1-hydroxy-3-(pyrrolidin-1-yl)propan-2-yl)acetamide (CCG-203586), in a suitable mouse model of type 3 Gaucher disease to ascertain whether it is an appropriate candidate for clinical development. The following hypothesis is to be tested. CCG-203586 will delay or prevent the onset of neurological deterioration and death in models of the neuronopathic Gaucher mouse. The specific aims of this project include the following: 1. To ascertain the optimal formulation of CCG-203586 for oral dosing. 2. To establish an assay for the measurement of CCG-203586 in blood and tissues, including brain. 3. To perform pharmacokinetic studies in wild type mice to determine the bioavailability, half-life, distribution, metabolism, and excretion of CCG-203586. 4. To treat the neuronopathic Gaucher mice with CCG-203586 either orally or parenterally to determine its efficacy in lowering peripheral tissue and brain glucosylceramide accumulation, delaying or preventing death, preventing histopathological changes in the brain, and inflammatory changes in the brain and peripheral tissues.