Optimization of novel pyranopyridine efflux pump inhibitors

 描述(由申请人提供)：革兰氏阴性病原体，包括肠杆菌科和铜绿假单胞菌的多重耐药(MDR)，对我们有效治疗由这些细菌引起的感染的能力构成了严重威胁。在革兰氏阴性菌中，MDR表型发展的一个主要组成部分是RND型外排泵的过度表达，它能主动地将抗菌药物和杀菌剂从周质输送到细胞外。显然，细菌外排泵是开发新的抗菌治疗的重要目标，这些治疗方法可以提高现有抗生素的效力，减少耐多药细菌的出现。在初步研究中，我们发现了一种新的吡喃并吡啶(MBX2319)，它是一种有效的AcrAB-TolC抑制剂，AcrAB-TolC是大肠杆菌和其他肠杆菌科细菌的主要外排泵。在第一阶段中，我们合成了MBX2319类似物，并对它们的效力、选择性、活性光谱和体外ADME性质进行了评估，以鉴定具有改善活性和类药物特性的化合物，并生成该系列的分子活性图谱。作为这项研究的结果，我们已经确定了类似物，它们在抗生素增强方面表现出20倍的增加，并满足成功完成第一阶段里程碑的标准。这一第二阶段项目的总体目标是进一步开发吡喃并吡啶系列，以确定23种体内验证的先导化合物，这些化合物适合于IND-Enabling临床前研究。在第二阶段，我们将利用一种将基于结构的药物设计与药物化学相结合的方法来设计和合成具有更好的活性光谱和ADMET特性的类似物，同时保持对肠杆菌科外排的效力。为了促进这一方法并探索其作用机制，我们将生成MBX2319的三维结构和与AcrB结合的类似物。类似物将在一组二级分析中进行评估，以确定化合物在动物身上的疗效和药代动力学(PK)研究的优先顺序。此外，从这些分析中得出的数据将为设计更多的化合物提供依据。通过化合物设计和评估的迭代过程，我们预计我们将识别出2-3个体内验证的具有良好PK和体内疗效的先导化合物。在第三阶段，这些外排泵抑制剂将被开发为与左氧氟沙星(LEV)或哌拉西林/他唑巴坦(PIP/TAZ)联合使用，作为该抑制剂系列的第一个治疗适应症，作为尿路和血液感染的辅助治疗。这些辅助疗法代表着对单一药物疗法的重大改进，因为它们将提供以下好处：1)在较低浓度下提高抗生素疗效，2)减少耐药性的演变。第二阶段的具体目标如下。目的1.对吡喃并吡啶系列化合物进行化学优化，合成用于动物安全性和有效性试验的先导化合物。目的2.根据效价、光谱、选择性、良好的体外粘附性对类似物进行优先排序。目的3.确定吡喃并吡啶类化合物与AcrB结合的三维结构及生化机制。目的4.在动物模型上评价铅化合物的急性毒性、药代动力学和药效。

 DESCRIPTION (provided by applicant): Multi-drug resistance (MDR) in Gram-negative pathogens, including the Enterobacteriaceae and Pseudomonas aeruginosa, poses a significant threat to our ability to effectively treat infections caused by these organisms. A major component in the development of the MDR phenotype in Gram-negative bacteria is overexpression of RND-type efflux pumps, which actively pump antibacterial agents and biocides from the periplasm to the outside of the cell. Clearly, bacterial efflux pumps are an important target for developing novel antibacterial treatments that increase the potency of existing antibiotics and decrease the emergence of MDR bacteria. In preliminary studies, we identified a novel pyranopyridine (MBX2319) that is a potent inhibitor of AcrAB-TolC, the major efflux pump of E. coli and other Enterobacteriaceae. MBX2319 enhances the activity of fluoroquinolones (FQs) and ß-lactam antibiotics against E. coli, but does not exhibit antibacterial activity alone nor is it cytotoxic.In Phase I we synthesized MBX2319 analogs and evaluated them for potency, selectivity, spectrum of activity, and in vitro ADME properties to identify compounds with improved activity and drug-like properties, and to generate a molecular activity map for this series. As a result of this research, we have identified analogs that exhibit a >20-fold increase in antibiotic potentiation and satisfy the criteria for successful completion of the Phase I milestones. The overall goal of this Phase II project is to further develop the pyranopyridine series to identify 23 in vivo validated lead compounds that are suitable for IND-enabling preclinical studies. In Phase II, we will utilize an approach that combines structure based drug design with medicinal chemistry to design and synthesize analogs with improved spectrum of activity and ADMET properties while maintaining potency against efflux by the Enterobacteriaceae. To facilitate this approach and probe the mechanism of action, we will generate a three dimensional structure of MBX2319 and analogs bound to AcrB. Analogs will be evaluated in a panel of secondary assays to prioritize compounds for efficacy and pharmacokinetic (PK) studies in animals. In addition, the data derived from these assays will inform the design of additional compounds. Through an iterative process of compound design and evaluation, we anticipate that we will identify 2-3 in vivo validated lead compounds with favorable PK and in vivo efficacy. In Phase III, these efflux pump inhibitors will be developed for use in combination with levofloxacin (LEV) or piperacillin/tazobactam (PIP/TAZ) as an adjunctive therapy for urinary tract and bloodstream infections as the first therapeutic indications for this inhibitor series. These adjunctive therapis represent a significant improvement over single agent therapies, because they will provide the following benefits: 1) increased antibiotic efficacy at lower concentrations, and 2) decreased evolution of resistance. The Specific Aims for Phase II are as follows. Aim 1. Chemically optimize the pyranopyridine series to generate lead compounds for animal safety and efficacy testing. Aim 2. Prioritize analogs by potency, spectrum, selectivity, favorable in vitro ADMET properties. Aim 3. Determine the three dimensional structure of pyranopyridines bound to AcrB and biochemical mechanism. Aim 4. Evaluate acute toxicity, pharmacokinetics, and efficacy of lead compounds in animal models.