Cardiac safety

Safeguarding the path to breakthrough medications.

Heartbeats and safety: Charting the course of drug development

Novel drug discovery begins at the preclinical laboratory bench as it is essential to answer basic questions concerning compound safety if a new compound is to progress to pharmaceutical development. Before any compound can be considered for dosing in healthy people, it undergoes a series of basic research in vitro and in vivo assays to determine its potential to cause toxicity against human organ systems, such as the heart, liver, or nervous system. It is of paramount importance to maximally de-risk its safety profile as early as possible in discovery to protect patients from unanticipated adverse events in the clinic, as well as control sky-rocketing development costs. The withdrawal of several drugs from the market in the last two

Cardiac Safety: The major
hurdle for new drugs in


De-risking proarrhythmic potential of drugs that could produce a fatal ventricular arrythmia known as Torsade de Pointes (TdP) has been front and center of drug development for over two decades. Cardiac safety pharmacologists use a combination of in vivo and in vitro assays to predict the risk of new therapeutics producing potentially fatal ventricular cardiac arrythmias. In particular, in vivo prolongation of the QT interval measured during an electrocardiogram (ECG)  is the gold standard surrogate marker for flagging proarrhythmic efficacy of new compounds.

However, the molecular and cellular mechanisms linking QT interval prolongation and TdP are complex and not fully understood. We know that many compounds that evoke TdP in patients have unequivocally been shown to inhibit a cardiac potassium ion channel called hERG. The biophysical consequence of hERG inhibition at the cellular level is delayed repolarization of the cardiac action potential which may cause TdP. However, the correlation is imperfect, because there are also example compounds that potently block the hERG channel, yet are not proarrhythmic in humans, such as the well-known L-type calcium channel inhibitor, Verapamil, still used by physicians to control blood pressure in millions of patients worldwide. Nevertheless, the present preclinical regulatory guidelines known as  ICH S7B mandate a patch-clamp electrophysiology test of compounds against the hERG ion channel and an in vivo QT test assessment. Because both of these tests are at best only surrogate markers of proarrhythmic activity of a compound, they highlight the important unmet need for the introduction of additional assays that better predict TdP. This insufficient availability of more predictive assays was, in 2013, an important catalyst for the formation of the “Comprehensive In Vitro Proarrhythmic Assay (CiPA) initiative”.

Cardiac Safety

The Comprehensive In Vitro Proarrhythmic Assay (CiPA) initiative is an ongoing global, public, and private collaboration with the aim of updating the existing cardiac safety testing paradigm (hERG and QT testing only) to better evaluate arrhythmia risk and removing the need for routine exhausting and expensive TQT studies. The CiPA work streams include: In SilicoMyocyteIon Channel, and Clinical Translation working groups. CiPA is focused on producing a broad standardized ion channel assay approach, incorporating defined patch-clamp assays for multiple important cardiac ion channels (IKr (hERG), ICa (L-type; Cav1.2), and INa (Nav1.5 peak and late current)). These results are being fed into an in-silico model of the human ventricular action potential that hopefully more accurately predicts the proarrhythmic efficacy of new compounds. And very importantly, the CiPA studies are systematically evaluating the compounds from the patch-clamp/in-silico experiments in human stem cell-derived cardiomyocytes using a variety of functional assay platforms with the primary goal of defining novel proarrhythmic predictive assays that identify changes in ventricular repolarization not necessarily anticipated by the ion channel/in-silico modeling predictions alone. The Steering Team is comprised of partners from the US FDA, HESI, CSRC, SPS, Japan NIHS, PMDA, EMA and Health Canada. A number of participating organizations, amongst them Nanion Technologies, build the backbone of the initiative.  We eagerly anticipate and await the ongoing publication of the CiPA studies in 2023 and beyond.


Recommended links:

New ICH E14/S7B Q&As and Training Materials, hosted by HESI and SPS

In-vitro best practices and ICH S7B considerations, hosted by FDA


Comprehensive experimental
approach to cardiac safety

APC, extracellular recordings and contractility

Nanion is a committee member of the Ion Channel HTS Team and a participant in the Myocyte Working Group. Nanion has a long-standing interest and extensive experience in automated patch clamp screening of cardiac ion channels. The Ion Channel Work Group finalized its phase I study in 2017. Besides further external sites, Nanion in Germany, USA, and Japan participated with the Patchliner and the SyncroPatch 384PE in this study.  Label-free contractility and extracellular field potential recordings of stem cell-derived cardiomyocytes (iPSC-CMs) are also available in our portfolio and were part of the Myocyte Working Group (CardioExcyte 96 and FLEXcyte 96). Our instruments are used for safety screening by major pharmaceutical companies and CROs worldwide and we are happy to assist you in setting up your CiPA assays.

HTS ion channel hERG results phase 1, excerpt

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