A novel, multiparametric cardiac safety assay using human myocytes

描述（由申请人提供）：近年来，一个主要的公共卫生问题是与使用非心脏药物相关的不良心脏事件（包括心源性猝死）的报告不断增加。事实上，在过去的15年中，六种非心脏药物在与获得性长QT综合征（acLQTS）相关后不得不退出市场，acLQTS的特征是尖端扭转型室性心动过速心律失常和心源性猝死。由于acLQTS对患者护理以及未来治疗化合物的开发具有巨大的影响，因此早期认识到治疗化合物的心脏责任是很重要的，为了降低acLQTS的发生率，监管机构与制药行业合作制定了评估新型测试化合物延迟心脏复极的潜力的指南。不幸的是，大多数已经建立的安全性测试不能可靠地识别通过与动作电位延长无关的机制产生心律失常的化合物，例如异常脉冲传导、复极动力学或钙调节异常。此外，大多数安全性试验是在异源表达系统或非人心肌细胞中进行的，这可能进一步限制其对人类风险的预测价值，因为心脏复极的种间差异。因此，许多心脏毒性化合物可能在常规安全筛选中未被检测到，但在药物开发的后期阶段或甚至在批准用于人类使用后显示出致心律失常。鉴于大多数临床前安全性测定的显著缺点，本提案旨在开发和验证一种新型的集成测定平台，该平台以高特异性和灵敏度检测广泛的致心律失常底物。我们的测定平台利用源自诱导多能干细胞的人心肌细胞和多个生理相关参数的基于荧光的记录，包括动作电位持续时间、钙瞬变和传导速度，以检测促心律失常事件的增加的风险。该提案的具体目标是：1。用一组充分表征的测试化合物来验证我们的新型测定平台。2.开发一种新的多参数算法，以评估具有高预测价值的预防性疾病风险。本提案中描述的集成测定平台有可能取代目前在电极导线发现和电极导线开发之间的界面使用的一整套临床前安全性测定，因为没有其他临床前安全性测定如此全面。

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 In fact, in the last 15 years six non-cardiac drugs had to be withdrawn from the market after being linked to acquired long QT syndrome (acLQTS) which is characterized by torsades de pointes arrhythmias and sudden cardiac death.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.