Identification of Novel Broad Spectrum Influenza Virus Inhibitors

描述(由申请人提供)：我们的目标是开发针对流感进入的小分子抑制剂。在第一阶段，我们鉴定了几种化合物，它们选择性地抑制血凝素(HA)介导的病毒进入过程。根据其抗病毒效力、选择性和化学可操作性，选择了三种HA特异性进入抑制剂(MBX494、MBX994和MBX726)进行进一步的研究和开发。这些流感抑制剂对多种流感病毒株表现出高效力(IC50=0.3-11M)和良好的选择性指数(SI&gt；20-200)，包括高致病性禽流感(HPAI)A/H5N1、2009年大流行性流感A/H1N1和耐奥司他韦的A/H1N1株。这些抑制剂还显示出与神经氨酸酶抑制剂奥司他韦的协同作用。MBX494、MBX994和MBX726以组特异性方式抑制组1 HA的H1和H5亚型，但不抑制组2 HA的H3或H7亚型。初步的作用机制(MOA)研究表明，这些化合物在感染早期起作用，并抑制HA介导的病毒-细胞膜融合过程。抑制剂未能阻断具有第2组HA、VSV和LASV的流感病毒，进一步表明它们不作用于细胞因素(例如，内体pH、唾液酸残基或病毒/细胞膜)。MBX494、MBX994和MBX726分别具有氨基烷基酚醚、氨基乙酰胺磺胺和简单磺胺支架。初步的化学优化已经产生了新的活性类似物，确定了这些化学支架适合进行优化。在第二阶段，我们将设计、合成和评估类似物作为HA特异性抑制剂。抑制剂的设计将受效力、靶点选择性、流行性感冒光谱、与奥司他韦的协同活性以及最低细胞毒性的驱动。将进一步评估最有希望的铅抑制剂的有利的(I)体外ADME特性，包括稳定性，以及(Ii)体内药代动力学(PK)和药效学(PD)特性，(Iii)毒性，和(Iv)动物模型的疗效，以选择最终的 临床前候选人。我们有五个具体目标。在目标1中，我们将设计和合成热门系列剧的类似物，以建立SAR并提高效力。我们还将使用基于结构的药物设计(SBDD)来增加抗流感效力(IC500.1M)并将细胞毒性降至最低(CC50100M)。在目标2中，我们将在体外评估这些类似物的效力和细胞毒性，以产生10-20个优先的线索。在目标3中，我们将通过评估体外“类药物”ADME特性来进一步确定抑制剂的优先顺序。在第四个目标中，我们将分析MOA的抗流感活性。在目标5中，我们将在小鼠模型中验证优先考虑的先导抑制剂的有效性和毒性，以确定最佳的临床前开发候选药物。目标1、2、3和5构成了临床前候选优化过程，因为它们共同提供了结构和活性、体外ADME和体内安全性和有效性之间的关系。了解新合成类似物的MOA将确保类似物保持所需的机制，而不会获得额外或不同的非特定机制。 公共卫生相关性：流感是一种高度传染性的急性呼吸道疾病，以每年反复流行和周期性的全球大流行为特征。疫苗，目前预防流感病毒感染的主要策略，只是 如果它们与流行的病毒类型(S)匹配，并且不能提前针对新出现的大流行毒株(S)开发，则有效。我们的目标是开发一种抗流感疗法，可用于治疗目前对神经氨酸酶抑制剂耐药的菌株和新的大流行菌株。

DESCRIPTION (provided by applicant): Our goal is to develop small molecule inhibitors that target influenza entry. In Phase I, we identified several compounds that selectively inhibit the hemagglutinin (HA) mediated virus entry process. Three HA specific entry inhibitors (MBX494, MBX994, and MBX726) were selected for further research and development based on their antiviral potency, selectivity and chemical tractability. These influenza inhibitors display high potency (IC50 = 0.3-11 ¿M) and favorable selectivity index values (SI>20-200) against a wide spectrum of influenza virus strains, including the high pathogenic avian influenza (HPAI) A/H5N1, 2009 pandemic influenza A/H1N1 and an oseltamivir resistant A/H1N1 strain. The inhibitors also displayed synergy with the neuraminidase inhibitor, oseltamivir. MBX494, MBX994, and MBX726 act in a group-specific manner to inhibit the H1 and H5 subtypes of group 1 HA but not the H3 or H7 subtypes of group 2 HA. Preliminary mechanism of action (MOA) studies suggest that the compounds act early during infection and inhibit the HA-mediated virus-cell membrane fusion process. Failure of the inhibitors to block influenza viruses with group 2 HA, VSV and LASV, further suggests that they do not act on cellular factors (e.g., endosomal pH, or sialic acid residues or viral/cell membrane). MBX494, MBX994, and MBX726 have aminoalkyl phenol ether, aminoacetamide sulfonamide and simple sulfonamide scaffolds respectively. Preliminary chemical optimization has already generated new active analogs, establishing the suitability of these chemical scaffolds for optimization. In Phase II, we will design, synthesize, and evaluate analogs as HA specific inhibitors. Inhibitor design will be driven by potency, target selectivity, influenza spectrum, synergistic activity with oseltamivir, ad minimal cytotoxicity. The most promising lead inhibitors will be evaluated further for favorable (i in vitro ADME properties, including stability, as well as (ii) in vivo pharmacokinetic (PK) and pharmacodynamic (PD) properties, (iii) toxicity, and (iv) efficacy in animal models to select final pre-clinical candidates. We have five specific aims. In Aim 1, we will design and synthesize analogs of the hit series to establish the SAR and improve potency. We will also use structure based drug design (SBDD) to increase the anti-influenza potency (IC50 <0.1 ¿M) and minimize cytotoxicity (CC50 >100 ¿M). In Aim 2, we will evaluate the analogs for potency and cytotoxicity in vitro to generate 10-20 prioritized leads. In Aim 3, we will further prioritize inhibitors by evaluating in vitro "drug-like" ADME properties. In Aim 4, we will analyze the MOA of anti-influenza activity. In Aim 5, we will validate the prioritized lead inhibitors for efficacy and toxcity in murine models to identify the best preclinical development candidate. Aims 1, 2, 3 and 5 constitute the preclinical candidate optimization process since together they provide the relationships between structure and activity, in vitro ADME and in vivo safety and efficacy in vivo. Understanding the MOA of the newly synthesized analogs will ensure that analogs maintain the desired mechanism and do not acquire additional or different non-specific mechanisms. PUBLIC HEALTH RELEVANCE: Influenza is a highly infectious acute respiratory disease, characterized by recurrent annual epidemics and periodic major worldwide pandemics. Vaccines, currently the primary strategy for protection against influenza virus infection, are only effective if they match the circulating virus type(s) and cannot be developed in advance against new emerging pandemic strain(s). Our goal is to develop an anti-influenza therapeutic that can be used to treat the current neuraminidase inhibitor resistant strains and new pandemic strains.