A novel, multiparametric cardiac safety assay using human myocytes

描述(由申请人提供)：近年来，与使用非心脏药物有关的不良心脏事件，包括心脏性猝死的报告一直在增加，这是一个主要的公共卫生问题。事实上，在过去的15年里，6种非心脏药物在与获得性长QT综合征(AcLQTS)有关后不得不退出市场，该综合征的特征是尖端扭转性心律失常和心脏性猝死。由于acLQTS对患者护理以及未来治疗化合物的发展具有巨大的影响，因此及早认识到治疗化合物的心脏易感性是重要的。为了减少acLQTS的发生率，监管机构与制药行业合作制定了指南，评估新测试化合物延缓心脏复极的潜力。不幸的是，已建立的大多数安全性测试都不能可靠地识别出与动作电位延长无关的机制导致心律失常的化合物，如异常的脉冲传导、复极动力学或钙调节失调。此外，大多数安全性测试要么是在异源表达系统中进行的，要么是在非人类心肌细胞中进行的，这可能会进一步限制它们对人类风险的预测价值，因为心脏复极的物种间差异。因此，许多心脏毒性化合物可能在传统的安全筛查中没有被检测到，但在药物开发的后期阶段，甚至在批准人类使用后，仍会出现心律失常。鉴于大多数临床前安全性测试的显著缺陷，本提案旨在开发和验证一种新颖的、集成的测试平台，该平台可以检测各种高特异性和高灵敏度的心律失常前基质。我们的检测平台利用来自诱导多能干细胞的人心肌细胞和基于荧光的多个生理相关参数的记录，包括动作电位时程、钙瞬变和传导速度，以检测心律失常事件风险的增加。该提案的具体目标是：1.用一组表征良好的测试化合物来验证我们新的分析平台。2.开发一种新的多参数算法来评估具有较高预测价值的心律失常风险。本提案中描述的集成分析平台有可能取代目前在铅发现和铅开发之间使用的一整套临床前安全分析，因为没有其他临床前安全分析如此全面。

DESCRIPTION (provided by applicant): A major public health concern in recent years has been increasing reports of adverse cardiac events, including sudden cardiac death, that have been associated with use of non-cardiac drugs. In fact, in the last 15 years six non-cardiac drugs had to be withdrawn from the market after being linked to acquired long QT syndrome (acLQTS) which is characterized by torsades de pointes arrhythmias and sudden cardiac death. Since acLQTS has enormous consequences for patient care as well as for the development of future therapeutic compounds, it is important that the cardiac liability of therapeutic compounds be recognized early on. To reduce the incidence of acLQTS, regulatory agencies in collaboration with pharmaceutical industry have instituted guidelines that assess the potential of novel test compounds to delay cardiac repolarization. Unfortunately, most safety tests that have been instituted do not reliably identify compounds that produce arrhythmias by mechanisms unrelated to action potential prolongation such as abnormal impulse conduction, repolarization dynamics or calcium dysregulation. In addition, most safety tests are performed either in heterologous expression systems or non-human cardiomyocytes which may further limit their predictive value for human risk due to interspecies variation in cardiac repolarization. Thus, many cardiotoxic compounds may go undetected in conventional safety screens yet demonstrate proarrhythmia during later stages of drug development or even after approval for human use. Given the significant shortcomings of most preclinical safety assays the present proposal has been designed to develop and validate a novel, integrated assay platform that detects a comprehensive range of proarrhythmia substrates with high specificity and sensitivity. Our assay platform utilizes human cardiomyocytes derived from induced pluripotent stem cells and fluorescent- based recordings of multiple physiological relevant parameters including action potential duration, calcium transients and conduction velocity to detect an increased risk for proarrhythmic events. The specific aims of the proposal are: 1. to validate our novel assay platform with a panel of well characterized test compounds. 2. To develop a novel multiparametric algorithm to assess proarrhythmic risk with high predictive value. The integrated assay platform described in the present proposal has the potential to supplant a whole battery of preclinical safety assays currently used at the interface between lead discovery and lead development as no other preclinical safety assay is as comprehensive.