Development of multispecific antibodies for the treatment of Pseudomonas aeruginosa infection

铜绿假单胞菌是引起广泛的医院和社区获得性感染的主要病原体。 感染.治疗这些感染的最大障碍是抗生素耐药性; 多重耐药（MDR）铜绿假单胞菌的感染是一个主要的公共卫生问题。因此，迫切需要 需要开发新的治疗方法，可以绕过细菌应用的耐药机制。 Inhibrx开发了一个基于单结构域抗体（sdAb）的平台，以开发新的 基于不同作用机制的抗生素，以避免耐药性的发展。这个平台 是模块化形式，其中多个骆驼科动物仅重链抗体结合结构域端对端连接， 与效应结构域（Fc）一起，以产生多特异性、多价抗体， 表位我们建议开发一种针对铜绿假单胞菌的治疗性抗体， 分泌的毒素以及细胞表面靶标，在分子中还含有功能性人IgG 1 Fc结构域。Inhibrx利用其多功能抗体形式开发了两种六价、三特异性、人源化的 对T3 SS毒力机制关键组分的两个表位具有特异性的分子 并且针对在所有铜绿假单胞菌菌株中高度保守的外膜脂蛋白。这些抗体 与所有测试的假单胞菌菌株结合，并在鼠感染模型中显示出改善的功效， 目前潜在的抗假单胞菌抗体疗法的领导者。 我们假设，基于这些抗体的治疗方法将被证明上级所有其他现有的铜绿假单胞菌 治疗学预期毒素阻断功能可保护募集到感染部位的免疫细胞， 而细胞结合能力将使细菌能够调理作用，随后是它们的吞噬作用， 通过免疫系统清除。在这个项目中，我们寻求通过研究性试验获得我们的候选抗体。 新药（IND）使毒理学。在第一阶段（具体目标#1），我们建议对这些抗体进行表征 它们在体外结合铜绿假单胞菌和阻断T3 SS依赖性细胞毒性的能力， 它们在体内感染模型中的功效，将其中一种确立为临床候选物。本项目二期 将专注于开展IND赋能研究，以促进在第三阶段中选择的候选抗体 临床试验。药代动力学（PK）将首先在人FcRn转基因小鼠中的特定目标#2中进行测试， 因为人抗体在野生型啮齿动物中通常具有相对短的半衰期。IND致能性多剂量毒性 然后将在非人灵长类动物（NHP）中进行研究，以确定我们的临床药物的安全性和PK。 候选人在该项目结束时，Inhibrx将开发出一种急需的抗体治疗剂。 用于治疗MDR假单胞菌，准备提交IND申请。我们希望这种治疗方法具有高度的影响力， 并对MDR铜绿假单胞菌感染具有转化作用。

Pseudomonas aeruginosa is a major pathogen that causes a wide range of hospital- and communityacquired infections. The greatest obstacle to treating these infections is antibiotic resistance; the rising prevalence of multidrug-resistant (MDR) P. aeruginosa is a major public health concern. Thus, there is an urgent need to develop novel therapeutics, which can circumvent drug resistance mechanisms applied by bacteria. Inhibrx has developed a platform based on single domain antibodies (sdAb) to enable development of novel antibiotics based on different mechanisms of action to circumvent the development of resistance. This platform is a modular format wherein multiple camelid heavy chain only antibody binding domains are joined end to end, together with an effector domain (Fc), to create multi-specific, multivalent antibodies targeting multiple epitopes. We propose to develop a therapeutic antibody against P. aeruginosa that simultaneously targets multiple secreted toxins as well as a cell-surface target, in a molecule that also contains a functional human IgG1 Fc domain. Inhibrx has used its versatile antibody format to develop two lead hexavalent, tri-specific, humanized molecules with specificity against two epitopes of a crucial component of the T3SS virulence mechanism and against an outer membrane lipoprotein that is highly conserved in all P. aeruginosa strains. These antibodies bind to all Pseudomonas strains tested and show improved efficacy in a murine infection model compared to the current leader in potential anti-Pseudomonas antibody therapeutics. We hypothesize that a therapeutic based on these antibodies will prove superior to all other existing P. aeruginosa therapeutics. Toxin blocking functionality is expected to protect immune cells recruited to the site of infection, while cell binding capability will enable opsonization of the bacteria, followed by their phagocytosis and clearance by the immune system. In this project we seek to take our candidate antibodies through Investigational New Drug (IND) enabling toxicology. In Phase I (Specific Aim #1) we propose to characterize these antibodies for their ability to bind P. aeruginosa and block T3SS dependent cytotoxicity in vitro and to compare their efficacy in in vivo models of infection, establishing one of them as a clinical candidate. Phase II of this project will focus on performing IND enabling research to facilitate taking the candidate antibody selected in Phase I to clinical trials. Pharmacokinetics (PK) will first be tested in Specific Aim #2 in human FcRn transgenic mice, as human antibodies generally have relatively short half-lives in wildtype rodents. IND-enabling multi-dose toxicity studies will then be performed in non-human primates (NHPs) to determine safety and PK of our clinical candidate. At the conclusion of this project, Inhibrx will have developed a much needed antibody therapeutic for treating MDR Pseudomonas that will be ready for IND filing. We expect this therapeutic to be highly impactful and transformative for MDR P. aeruginosa infections.