The role of CYP3A7 in the disposition and Toxicity of HIV inhibitors in the developing infant

CYP3A7 在 HIV 抑制剂对发育中婴儿的处置和毒性中的作用

• 批准号: 10012258
• 负责人: Jed Noah Lampe
• 金额: $ 41.26万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10012258
• 关键词: Achievement; Active Sites; Adult; Affect; Affinity; Amino Acids; CYP3A4 gene; Crystallization; Cytochrome P450; Data; Development; Drug Interactions; Drug Kinetics; Drug Metabolism Inhibition; Drug Monitoring; Drug Prescriptions; Drug toxicity; Drug usage; Enzymes; Fostering; Gestational Age; Goals; HIV; Health; Hepatotoxicity; Human; In Vitro; Infant; Knowledge; Lead; Life; Ligands; Liver; Liver Microsomes; Lopinavir; Mediating; Metabolic; Metabolism; Modeling; Nelfinavir; Nevirapine; Pharmaceutical Preparations; Physiological; Population; Premature Infant; Production; Proteins; Public Health; Publishing; Recombinants; Reporting; Research; Ritonavir; Roentgen Rays; Role; Safety; Site; Structure; Testing; Therapeutic; Toxic effect; United States National Institutes of Health; Vulnerable Populations; X-Ray Crystallography; base; clinically relevant; drug clearance; drug disposition; drug efficacy; drug metabolism; efavirenz; enzyme structure; functional group; improved; improved outcome; inhibitor/antagonist; innovation; medication safety; metabolic profile; neonatal infection; neonate; novel; novel therapeutics; pediatric patients; pharmacokinetic model; physiologically based pharmacokinetics; preclinical development; safety testing; success

ABSTRACT Each year sick and premature infants infected with HIV are treated with a variety of drugs, despite the fact that these drugs have never been tested for safety and efficacy in this vulnerable population. A primary determinant for the pharmacokinetic (PK) and hepatotoxicity profile of many of these drugs is cytochrome P450 metabolism. CYP3A7 is the predominant P450 enzyme in the in the developing infant (≤6 mos. Post- Gestational Age). Recently published reports and our own preliminary results have demonstrated that CYP3A7 can produce a metabolic profile significantly different than that of adult CYP3A4. These differences in metabolism can alter the PK parameters and safety profiles of many HIV drugs used in pediatric patients, leading to reduced efficacy or increased toxicity. Therefore, there exists a critical need to determine the PK and metabolic profiles of clinically relevant CYP3A7 HIV drug substrates to the improve safety and efficacy of these drugs in infants. The objective of this proposal is to determine the functional consequences and mechanistic basis of the differences in HIV drug metabolism between CYP3A7 and adult CYP3A4. Our specific hypothesis is that the differences in HIV drug metabolism are due to changes in enzyme structure which lead to substantial alterations in drug clearance, drug-drug interactions, and production of reactive metabolites. Our first aim is to develop a physiologically based PK (PBPK) model for the disposition of four commonly prescribed HIV inhibitors: ritonavir, lopinavir, nevirapine, and efavirenz. To achieve this, we will monitor drug metabolism and identify metabolites in vitro with both recombinant CYP3A7 and CYP3A4 enzymes and human liver microsomes (HLMs) from the adult and the infant at different stages of development. We will utilize the results from these studies to produce predictive PK models for the developing infant. Our second aim is to identify the CYP3A7 inhibitory capacity, potential drug-drug interactions, and reactive metabolites for each of these inhibitors. Finally, our third aim is to define the structural basis of the differences in HIV drug metabolism observed between CYP3A7 and CYP3A4. To do this, we propose to obtain an X-ray crystal structure for CYP3A7 with the substrates ritonavir and nevirapine, and perform Saturation Transfer Difference NMR to identify amino acid residues and ligand functional groups that are important for enzyme-ligand interaction. We expect that these studies will allow us to determine how structural differences contribute to the observed metabolic differences. The proposed research is innovative because it seeks to change the current conceptual framework by producing improved infant PBPK models for HIV drug disposition using HLMs, and novel crystal structures for this important enzyme. This research will improve health outcomes by improving our ability to accurately predict pharmacokinetics and drug-drug interactions of some important HIV drugs prescribed to the developing infant. Additionally, it will positively impact our ability to understand CYP3A7 HIV drug metabolism based on structure, which will be useful in the development of new drugs specifically targeted to infants.

抽象的 每年感染了艾滋病毒的病人和过早的婴儿都用多种药物治疗，dospite 事实证明，这些药物从未在这种脆弱人群中测试过安全和效率。主要 这些药物的药代动力学（PK）和肝毒性谱的决定因素是细胞色素P450 代谢。 CYP3A7是发育中的婴儿中的主要P450酶（≤6os。 胎龄）。最近发布的报告和我们自己的初步结果表明CYP3A7 可以产生与成年CYP3A4的代谢谱明显不同。这些差异 代谢可以改变小儿患者使用的许多HIV药物的PK参数和安全性。 导致效率降低或毒性增加。因此，存在确定PK的迫切需要 临床相关的CYP3A7 HIV药物底物的代谢谱，以提高安全性和效率 婴儿中的毒品。该提案的目的是确定功能后果和机制 CYP3A7和成人CYP3A4之间HIV药物代谢差异的基础。我们的具体假设 是，HIV药物代谢的差异是由于酶结构的变化，这导致 药物清除，药物相互作用和反应性代谢产物的产生的实质性改变。我们的 第一个目的是开发一个基于物理的PK（PBPK）模型，以处理四种 规定的HIV抑制剂：Ritonavir，Lopinavir，Nevirapine和Efavirenz。为了实现这一目标，我们将监控药物 与重组CYP3A7和CYP3A4酶和人类的体外代谢并鉴定代谢物 来自成人和婴儿在不同发育阶段的肝微粒体（HLM）。我们将利用 这些研究的结果是为发育中的婴儿产生预测性PK模型。我们的第二个目标是 确定CYP3A7抑制能力，潜在的药物相互作用以及每一个的反应性代谢产物 这些抑制剂。最后，我们的第三个目标是定义HIV药物代谢差异的结构基础 在CYP3A7和CYP3A4之间观察到。为此，我们建议获得X射线晶体结构 CYP3A7与底物利托那韦和奈韦拉平，并执行饱和转移差NMR到 确定对于酶 - 配体相互作用很重要的氨基酸残留物和配体官能团。我们 预计这些研究将使我们能够确定结构差异如何促进观察到的 代谢差异。拟议的研究具有创新性，因为它试图改变当前的概念 通过生产改进的婴儿PBPK模型，使用HLM和新型晶体产生用于HIV药物处置的框架 这种重要酶的结构。这项研究将通过提高我们的能力来改善健康状况 准确预测某些针对该药物的一些重要艾滋病毒药物的药代动力学和药物相互作用 发展婴儿。此外，这将对我们了解CYP3A7 HIV药物代谢的能力产生积极影响 基于结构，这将在针对婴儿的新药物的开发中有用。