Optimization and preclinical characterization of anthranilamide derivatives for Alzheimer prevention

阿尔茨海默病(AD)是一种毁灭性的痴呆症，没有疾病修正治疗。根据 FDA，AD临床试验超过200项，但到目前为止，在减缓AD进展方面没有取得任何成功。这种连续不断的 失败说明了这项任务的难度，并要求重新评估现有的治疗策略。 作为一种神经退行性疾病，神经元死亡是AD发病的基础。目前的治疗方法 策略集中于对抗AD所涉及的神经毒性侮辱(即Aβ、磷酸-tau、自由基、 炎性毒素等)。对于加强神经元防御的关注较少，因为神经元 死亡是它的防御和侮辱之间的不平衡。我们实验室的研究揭示了人的防御机制 携带G蛋白偶联受体(GPCRK-5)的AD患者中枢胆碱能系统受损 (GRK5)缺乏；后者在衰老过程中出现，并在AD时恶化。受损的神经元防御系统 易受Aβ过量或缺氧引起的变性的影响，而活性邻氨基苯甲酰胺 衍生物CN168可预防GRK5缺陷大鼠的神经退行性变和认知功能障碍 瑞典APP转基因(GAP)小鼠。因此，新出现的证据支持这样一种观点，即 神经元防御提高了神经元死亡阈值，从而增加了各种神经毒性攻击的难度 引发神经元死亡。这一新的治疗策略侧重于防御而不是个人侮辱，但 可同时抵抗多种侮辱。这样的治疗努力不会取代，而是补充， 现有的治疗努力，因此为发现AD的疾病修饰疗法带来了新的希望。 而CN168被证明在概念验证(PoC)水平上在预防认知 在GAP小鼠中，我们还注意到CN168有两次违反了五个类药物规则(MW&GT；500； LogP&gt；5)，中央行动持续时间较短。这就要求进一步优化药代动力学(PK)。 CN168的特性在未来的临床研究之前。因为CN168已经在体内证明了疗效，而且以前 表现出对M受体-2的极高选择性和敏感性，我们建议使用CN168作为 活性药物成分(API)，并采用前药方法改善其脑与血浆(B2P)的比率。 在本项目中，我们将通过比较CN168的PK特性来表征精心挑选的三种CN168前药， 并在制备新药(IND)前研究其药效学(PD)和毒理学 申请最终入选的前药(S)。我们将通过以下三个具体目标实现目标： 目的1.原料药(CN168)及其前药的药代动力学 CN168及其前体药物在体内足以进行PK图谱的数量；然后(2)进行其PK 表征并选择性能优于CN168的前药(S)，其B2P比率有所改善。 目的2：选定的CN168前药的药效学和毒理学：为此，我们 将执行(1)PD研究，用于目标接合验证、有效剂量范围发现和评估 GRK5-Deifienct小鼠和野生型小鼠的潜在副作用；以及(2)药物毒性研究，包括 体外和体内急性毒性、重复给药毒性和长期(9个月)毒性。 目标3：药物cGMP的制造和工业应用：为此，我们将(1)制造 在美国国内的cGMP工厂的最终前药；以及(2)准备向FDA提交IND申请。 AD是世界上最持久、最具破坏性的痴呆症。然而，临床试验的目的是找到一种 阿尔茨海默病的疾病修饰疗法相继失败。几十年来对GRK5缺乏症的研究 在AD中，我们提出了一种新的治疗策略，与现有的治疗策略截然不同，但可能是对现有策略的补充 专注于个人侮辱的治疗努力。我们已经通过API CN168获得了PoC证据。进一步 其PK特性的改进将确保其在临床前阶段的成功，并为其成功迈向 翻译成未来的临床试验。我们认为这是开发AD疾病修正疗法的机会。

Alzheimer's disease (AD) is a devastating dementia without a disease-modifying therapy. According to FDA, AD clinical trials are over 200 but so far have made zero success in slowing AD progression. This continuous failure speaks for the difficulty of this task and calls for re-evaluating the existing therapeutic strategies. As a neurodegenerative disorder, neuronal death is fundamental to AD pathogenesis. Current therapeutic strategies concentrate on combating neurotoxic insults implicated in AD (i.e., Aβ, phospho-tau, free radicals, inflammatory toxins, etc.). Less attention has been paid to strengthening neuronal defense given that neuronal death is an imbalance between its defense and insult. Studies in our lab revealed that defense mechanism of central cholinergic system in AD is compromised in subjects with G protein-coupled receptor (GPCR) kinase-5 (GRK5) deficiency; the latter appears during aging and worsens in AD. The compromised neuronal defense leads to susceptibility to degeneration triggered by excessive Aβ or hypoxia whereas an active anthranilamide derivative CN168 was able to prevent the neurodegeneration and the cognitive impairments in GRK5-deficient Swedish APP transgenic (GAP) mice. Therefore, emerging evidence supports the idea that strengthening neuronal defense raises neuronal death threshold thus increasing the difficulty for various neurotoxic insults to trigger neuronal death. This new therapeutic strategy focuses on the defense rather than individual insult but works against multiple insults simultaneously. Such a therapeutic effort will not replace, but rather complement, the existing therapeutic effort, therefore bringing new hope for discovering disease-modifying therapy for AD. While CN168 was proven to be effective at the level of proof-of-concept (PoC) in preventing cognitive decline in GAP mice, we also noticed that CN168 has two violations of the five drug-likeness rules (MW>500; LogP>5), with a short duration of central action. This requires further optimization of the pharmacokinetic (PK) properties of CN168 prior to future clinical studies. Because CN168 has proven in vivo efficacy and previously demonstrated superb selectivity and sensitivity towards muscarinic receptor-2, we propose to use CN168 as the active pharmaceutical ingredient (API) and to improve its brain to plasma (B2P) ratio using prodrug approach. In this project, we will characterize three carefully selected prodrugs of CN168 by comparing their PK properties, and study their pharmacodynamics (PD) and toxicology before preparing the investigational new drug (IND) application for the finally selected prodrug(s). We will achieve our goals with the following three Specific Aims: Aim 1. Pharmacokinetics of the API (CN168) and its prodrugs: in this aim we will (1) synthesize CN168 and its prodrugs in quantities sufficient for their PK profiling in vivo; and then (2) carry out their PK characterization and select the prodrug(s) outperforming CN168 with improved B2P ratios. Aim 2: Pharmacodynamics and toxicology of the selected CN168 prodrugs: in this aim, we will perform (1) PD studies for target engagement verification, effective dose range finding, and evaluation of potential side effects in GRK5-deifienct mice along with wild type mice; and (2) Drug toxicity studies, including in vitro and in vivo acute toxicity, and repeated dosing toxicity and long-term (9 months) toxicity. Aim 3: Drug cGMP manufacturing and IND application: In this aim, we will (1) manufacture the final prodrugs domestically in the US at a cGMP facility; and (2) prepare for the IND application to FDA. AD is the most persistent and devastating dementia worldwide. Yet the clinical trials aimed at finding a disease-modifying therapy for AD have failed one after another. Through decades of research on GRK5 deficiency in AD we came up a new therapeutic strategy that is distinct from, but may complement with, the existing therapeutic efforts that focus on individual insult. We have obtained PoC evidence with the API CN168. Further improvement of its PK properties will ensure its success at preclinical stage and ease its way towards a successful translation to future clinical trial. We believe this is a chance to develop a disease-modifying therapy for AD.