Rapid Development of a Lead Aromatic Aldehyde Derivative with both Oxygen Dependent and Novel, Oxygen Independent Anti-Sickling Effects: Building on a Paradigm Shift in Sickle Cell Disease Therapy

镰状细胞病（SCD），由血红蛋白（Hb）的基因突变引起的红细胞 （红细胞）变得畸形和僵硬（“镰状”），影响了大约10万美国人（和数百万人） 全球范围内），美国医疗保健系统每年的估计成本超过10亿美元。红细胞镰状化， 下游SCD不良反应的主要原因，包括疼痛危象、进行性器官损伤，以及， 最终过早死亡，是细胞内脱氧“紧张”（T- 状态）镰状型血红蛋白（HbS）（只有T-状态HbS倾向于折叠，而不是氧（O2）-配体 “松弛”（R-状态）HbS）。因此，RBC镰状化通常在缺氧条件下发展。近期 FDA批准的Voxelotor是一类新的潜在疾病修饰药物中的第一种，为 SCD治疗方式的范式转变。在批准Voxelotor之前， 新的治疗方法针对疾病的根本原因在二十多年。芳香醛- 含有化合物，如Voxelotor，通过变构结合， 稳定HbS的高O2亲和性R-状态，其不被破坏。使用迭代的、基于结构的 我们的药物化学家团队在过去的15年里一直专注于开发芳香族化合物， 通过合理修饰天然化合物而具有增强的治疗潜力的含环糊精的类似物， 例如香草醛。在X射线共晶体学和分子模拟的指导下，香草醛衍生物 通过引入栓系吡啶部分， 具有不同的替换和修改。我们的主要治疗候选药物VZHE-039的独特之处在于，它不 不仅通过O2依赖性机制提供显著增加的Hb变构调节， 与Hb α F-螺旋分子间接触，通过O2直接破坏聚合物的形成 独立机制。这种新型的双重作用机制，不仅是O2依赖性的， 提供甚至更有效的抗镰状效应而不固有地限制组织O2卸载的潜力。 基于大量令人鼓舞的初步体外和体内数据，我们开发了一种 研究策略将促进快速过渡到第二阶段SBIR研究，并随后进行 研究性新药（IND）申请。第一阶段提案的主要目标是确定和评估 VZHE-039的最佳口服制剂，以改善胃肠道溶解度和口服生物利用度。的 将在大鼠和小鼠中评价优化的制剂以确定其药代动力学和 单次口服给药的药效学特征，以及多次重复给药暴露于稳定 状态具有改善的体内口服生物利用度和最佳稳态动力学的药剂将准备用于 SCD小鼠模型中的确定性疗效研究，以及在高等哺乳动物中的IND使能毒理学。

Sickle cell disease (SCD), which results from a genetic mutation in hemoglobin (Hb) that causes red blood cells (RBCs) to become malformed and rigid (‘sickled’), affects approximately 100,000 Americans (and millions worldwide), with an estimated cost to the US healthcare system of over $1B annually. Red blood cell sickling, the primary cause of downstream adverse SCD effects, including painful crises, progressive organ damage, and, eventually premature death, is a consequence of the intracellular polymerization of deoxygenated “Tense” (T- state) sickle-type Hemoglobin (HbS) (only T-state HbS tends to polymerize and not oxygen (O2)-liganded “Relaxed” (R-state) HbS). Therefore, RBC sickling typically develops under conditions of hypoxia. The recent FDA approval of Voxelotor, the first in a new class of potentially disease-modifying drugs, sets the stage for a paradigm shift in the way SCD is therapeutically managed. Prior to the approval of Voxelotor, there had been no new therapeutics targeting the underlying cause of the disease in more than two decades. Aromatic aldehyde- containing compounds, such as Voxelotor, address the primary etiology of SCD by allosterically binding to, and stabilizing, the high O2 affinity R-state of HbS, which does not polymerize. Using an iterative, structure-based approach, our team of medicinal chemists has, for over 15 years, been focused on developing aromatic aldehyde-containing analogs with enhanced therapeutic potential by rationally-modifying natural compounds, such as vanillin. Guided by insights from X-ray co-crystallography and molecular modeling, vanillin derivatives with increasing potency and duration of action have been attained by incorporating a tethered pyridine moiety with diverse substitutions and modifications. Our lead therapeutic candidate, VZHE-039, is unique in that it not only provides significantly increased Hb allosteric modulation via an O2 dependent mechanism, but also engages in inter-molecular contacts with the Hb αF-helix, which directly destabilizes polymer formation via an O2 independent mechanism. This novel dual mechanism of action, which is not solely O2 dependent, has the potential to provide for even more potent anti-sickling effects without inherently limiting tissue O2 unloading. Based on a significant body of highly encouraging, preliminary in vitro and in vivo data, we have developed a research strategy that will facilitate a rapid transition to Phase II SBIR studies and, subsequently, an Investigational New Drug (IND) application. The principle goal of this Phase I proposal is to identify and evaluate an optimal oral formulation for VZHE-039 to improve gastrointestinal solubility and oral bioavailability. The optimized formulation will be evaluated in both rats and mice to determine its pharmacokinetic and pharmacodynamic profile with single oral doses of the drug, as well as multiple repeat dose exposure to steady state. An agent with improved in vivo oral bioavailability and optimal steady state kinetics will be ready for definitive efficacy studies in an SCD mouse model, as well as IND-enabling toxicology in higher order mammals.