Polymerase Inhibitors of Respiratory Syncytial Virus

摘要 呼吸道合胞病毒(RSV)是#年婴儿因传染病住院的主要原因 美国。在季节性流行期间，成人可能会在一生中定期再次感染，但也可能 有生命危险，尤其是对老年人和免疫功能受损的人。尽管进行了广泛的研究，但没有 疫苗保护是可用的，目前以抗体疗法为基础的免疫预防仍然保留 高危患者。认识到对有效、适用和耐受性良好的RSV的临床需求尚未得到满足 治疗，这是这个项目的目标是追求严格的临床前特征和降低风险 我们在以前的工作中确定的两个口服有效的RSV聚合酶抑制剂的程序 和初步研究。 首创RSV报告病毒技术，完成大规模高通量抗RSV 药物筛选活动，我们已经确定了两个结构和机械上不同的打击类别，两者都 抑制RSV RNA依赖的RNA聚合酶(RdRP)复合体，一种新的尿苷核苷类似物和 启动Rdrp介导的RNA合成的非竞争性抑制物。当前线索显示 对RSV报告菌株和临床分离株的有效活性，纳摩尔抑制浓度 与疾病相关的高分化原代人呼吸道上皮细胞培养，良好的药代动力学(PK) 具有持续的血药浓度和良好的初步耐受性。初步研究已经确定 在RSV感染小鼠模型中口服有效性的概念验证，降低肺部病毒载量和标志物 呼吸道合胞病毒毛细支气管炎的临床症状。这个项目将从双管齐下追求RSV聚合酶的目标。 战略，同时开发底物类似物和非竞争性抑制剂类别，以主动 减轻早期失败的风险，或为未来用作配伍药物奠定实验基础。 最初的方法将针对任一系列单独定制，旨在识别和解决潜在问题 在流程的早期阶段，针对特定类别的负债。核糖核苷类似物铅显示出持续的组织 活性三磷酸盐的浓度和口服消毒抗呼吸道合胞病毒的效果。在准备正式的 发展，这一类将受到作用机制的刻画，抵抗剖析 RSV目标和脱离目标影响的评估(目标1)。第一代非竞争性抑制剂Lead 已经成功地描述了抗性、细胞毒性和机制，但必须受到最终结构的影响 以及QSAR引导下的效价和PK性质的合成优化，以揭示其全部抗病毒潜力(AIM 2)。使用RSV感染的小鼠模型将降低任何一类新出现的确认导联的风险， 将评估复合经历过的RSV群体的致病机制，并将PK图谱与 在原代人类呼吸道上皮细胞培养中的性能，以告知模拟生理、 在相关人体组织模型中动态药物浓度对抗病毒疗效和安全边际的影响(目标3)。

Summary Respiratory syncytial virus (RSV) is the primary cause of infant hospitalization from infectious diseases in the United States. Regular re-infection of adults can occur throughout life during seasonal epidemics, but can be life-threatening especially to the elderly and the immunocompromised. Despite extensive research, no vaccine protection is available and current antibody therapy-based immunoprophylaxis remains reserved for high-risk patients. Recognizing the unmet clinical need for efficacious, applicable, and well-tolerated RSV therapeutics, it is the goal of this project to pursue a rigorous preclinical characterization and de-risking program of two orally efficacious RSV polymerase inhibitor classes that we have identified in previous work and pilot studies. Having pioneered RSV reporter virus technology and completed large-scale high-throughput anti-RSV drug screening campaigns, we have identified two structurally and mechanistically distinct hit classes that both inhibit the RSV RNA-dependent RNA polymerase (RdRP) complex, a novel uridine ribonucleoside analog and a non-competitive inhibitor of initiation of RdRP-mediated RNA synthesis at the promoter. Current leads show potent activity against RSV reporter strains and clinical isolates, nanomolar inhibitory concentrations in disease-relevant well-differentiated primary human airway epithelia cultures, good pharmacokinetic (PK) profiles with sustained plasma concentrations, and good preliminary tolerability. Pilot studies have established proof-of-concept of oral efficacy in the mouse model of RSV infection, reducing lung viral load and hallmark clinical signs of RSV bronchiolitis. This project will pursue the RSV polymerase target in a two-pronged strategy, developing the substrate-analog and non-competitive inhibitor classes simultaneously to proactively mitigate the risk of early stage failure or lay the experimental foundation for future use as companion drugs. The initial approach will be tailored individually to either series, designed to identify and address potential class-specific liabilities early in the process. The ribonucleoside analog lead has shown sustained tissue concentrations of the active triphosphate form and sterilizing oral anti-RSV efficacy. In preparation of formal development, this class will be subjected to mechanism of action characterization, resistance profiling against the RSV target, and assessment of off-target effects (aim 1). The first-generation non-competitive inhibitor lead has been successfully resistance, cytotoxicity, and mechanism profiled, but must be subjected to final structure and QSAR-guided synthetic optimization of potency and PK properties to uncover its full antiviral potential (aim 2). Emerging confirmed leads of either class will be de-risked using the mouse model of RSV infection, pathogenesis of compound-experienced RSV populations will be assessed, and PK profiles correlated with performance in primary human airway epithelium cultures to inform simulations of the impact of physiological, dynamic drug concentrations on antiviral efficacy and safety margin in relevant human tissue models (aim 3).