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，我们发现了几种选择性抑制血凝素（HA）介导的病毒进入过程的化合物。3种HA特异性进入抑制剂（MBX494， MBX994和MBX726）根据其抗病毒效力，选择性和化学可追溯性选择进行进一步的研究和开发。这些流感抑制剂对广泛的流感病毒株，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，显示出高效价（IC50 = 0.3-11¿M）和良好的选择性指数值（SI>20-200）。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以群体特异性的方式抑制1组HA的H1和H5亚型，而不抑制2组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，抑制ha介导的病毒-细胞膜融合过程。抑制剂不能阻断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子（例如，内体pH值、唾液酸残基或病毒/细胞膜）。MBX494、MBX994和MBX726分别有氨基烷基酚醚、氨基乙酰胺磺酰胺和简单磺酰胺支架。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的优化适用性。在第二阶段，我们将设计、合成和评估作为HA特异性抑制剂的类似物。抑制剂的设计将由效力、靶标选择性、流感谱、与奥司他韦的协同活性和最小的细胞毒性驱动。最有希望的铅抑制剂将进一步评估其良好的(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，以及（iv）动物模型中的功效，以选择最终的药物

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.