Thioredoxin mimicry: novel treatment of toxicant-mediated inhalational lung injur

描述（由申请人提供）：Radikal Therapeutics发明了一种新型硫氧还蛋白（Trx）模拟物，用于吸入有毒气体光气（COCl2）、硫化氢（H2S）和氯（Cl2）引发的急性肺损伤（ALI）的复苏。Trx是治疗吸入性毒物介导的肺损伤的理想药物靶点，因为它作为细胞内的主开关，调节Trx超家族蛋白的活性，这些蛋白控制细胞保护、炎症和凋亡。我们的候选分子（R-911）是一种具有稳定巯基的前药，与血浆接触后立即转化为母体形式，具有功能活性的Trx模拟物（R-952）。吸入Cl2和COCl2或注射H2S供体NaSH后，用R-911进行复苏可显著降低小鼠的组织学损伤、炎症和死亡率。目的1：明确R-911在小鼠吸入COCl2和H2S暴露复苏中的药效学、治疗时间窗、最佳给药计划和作用机制。Balb/c小鼠将全身暴露于COCl2或H2S中20分钟。A系列：在吸入暴露后1天和7天安乐死时，将对肺组织和支气管肺泡液进行一系列临床相关损伤指标评分：形态学、渗出性炎症、氧化还原应激、表面活性剂表达和活性、促炎和抗炎基因表达、粘膜屏障功能障碍和线粒体完整性。这些生物标记物将与血浆和肺组织中R-911及其亲本R-952的浓度相关联，以便构建药效学概况，指导大型动物和临床剂量。B系列：A系列中阐明的最佳R-911给药参数（剂量、给药计划、起始时间）将用于Balb/c小鼠28天的研究，在暴露于COCl2和H2S后追踪体重和存活率。目的2：建立R-911在COCl2和H2S吸入暴露犬模型中的药效学特征。我们将在有意识的、自发呼吸的犬中建立COCl2和H2S的最佳浓度，以产生可重复的、具有临床意义的ALI模型。接下来，我们将在选定的浓度下进行安慰剂对照疗效研究，并建立在COCl2和H2S暴露结束30分钟后开始的im给药R-911（安慰剂+ 3剂量水平）的剂量依赖性。R-911的疗效将通过对ALI生物标志物和肺分流及力学的影响来证实。目标3：根据BIOSHIELD指南，在毒理学、ADME/PK和安全药理学ind支持研究中建立R-911的急性安全性、稳定性和耐受性。扩大生产gmp级R-911，开展glp级ADME/PK、安全药理学、遗传毒理学、大鼠、犬体内毒理学研究。将编制完整的IND申请并提交给FDA，以支持有效性和安全性研究。

DESCRIPTION (provided by applicant): Radikal Therapeutics has invented a novel class of thioredoxin (Trx) mimetics intended for the resuscitation of acute lung injury (ALI) triggered by inhalation of the toxic gases phosgene (COCl2), hydrogen sulfide (H2S), and chlorine (Cl2). Trx is an ideal pharmaceutical target for treatment of inhalational toxicant-mediated lung damage because it acts as a master intracellular switch regulating the activity of the Trx superfamily of proteins that govern cytoprotection, inflammation, and apoptosis. Our candidate molecule (R-911) is a prodrug with stabilized thiol groups that undergoes immediate conversion upon contact with plasma to its parent form, the functionally active Trx mimetic (R-952). Resuscitation with R-911 profoundly reduces histologic injury, inflammation, and mortality of mice subjected to inhalation of Cl2 and COCl2 or injection of the H2S donor NaSH. Aim #1: Define the pharmacodynamics, therapeutic time window, optimal schedule of administration, and mechanism of action of R-911 in the resuscitation of murine COCl2 and H2S inhalational exposure. Balb/c mice will be exposed for 20 min to whole-body COCl2 or H2S. Series A: Upon euthanasia at 1 and 7 days post-inhalation exposure, lung tissue and bronchoalveolar fluid will be scored on a battery of clinically-relevant injury indices: morphology, exudative inflammation, redox stress, surfactant expression and activity, pro-inflammatory and anti- inflammatory gene expression, mucosal barrier dysfunction, and mitochondrial integrity. These biomarkers will be correlated with the concentrations of R-911 and its parent form R-952 in plasma and lung tissue in order to construct a pharmacodynamic profile that will guide large animal and clinical dosing. Series B: The optimal R-911 dosing parameters (quantity, dose schedule, time of initiation) elucidated in Series A will be utilized in a 28-day study in Balb/c mice wherein body weight and survival are tracked after exposure to COCl2 and H2S. Aim #2: Establish the pharmacodynamic profile of R-911 as a rescue therapy in canine models of COCl2 and H2S inhalational exposure. We will establish the optimal concentrations of COCl2 and H2S in conscious, spontaneously breathing canines that yield a reproducible and clinically significant model of ALI. We will next conduct placebo-controlled efficacy studies at the selected concentrations, and establish the dose-dependence of IM-administered R-911 (placebo + 3 dose levels) initiated 30 minutes after the end of COCl2 and H2S exposures. Efficacy of R-911 will be confirmed by the impact on ALI biomarkers and pulmonary shunt and mechanics. Aim #3: Establish the acute safety, stability, and tolerance of R-911 in toxicology, ADME/PK, and safety pharmacology IND-enabling studies per BIOSHIELD guidelines. We will scale-up and manufacture GMP-grade R-911 and carry out GLP-grade ADME/PK, safety pharmacology, genetic toxicology, and in vivo toxicology investigations in rats and dogs. A full IND application will be compiled and submitted to the FDA to support efficacy and safety studies.