CiPA - Comprehensive in vitro Proarrhythmia Assay
The Comprehensive In Vitro Proarrhythmia Assay (CiPA) initiative aims to replace the preclinical hERG current assay required under the ICH S7B safety pharmacology guidelines and clinical TQT study, which provides a surrogate marker of Proarrhythmia, with more translationally relevant assessments of proarrhythmic risk (Sager et al., 2014). CiPA intend to achieve this by evaluating proarrhythmic risk of evolving drug candidates based on an understanding of the electrophysiologic mechanisms responsible for proarrhythmia linked to Torsades de pointes (TdP) and QT prolongation.
The Q&As draft as endorsed August 2020 describe how nonclinical assays can be used as a part of an integrated risk assessment prior to first-in-human studies as they are used today, and in later stages of clinical development as a part of a combined nonclinical-clinical integrated risk assessment. If implemented, they can lead to a reduction in the number of ‘Thorough QT’ clinical studies and improved decision making at the time of a marketing application.
A webinar (Oct 15 and 16, 2020) will cover the background, motivation for, and overview of the new Q&As for ICH E14/S7B, followed by presentations on each of the main Q&A topics:
ICH E14 and S7B: Webinar on the recently released Draft Q&As
The CiPA workstreams
The Comprehensive in Vitro Proarrhythmia Assay (CiPA) paradigm was initiated in 2013. 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. The CiPA work streams include: In Silico, Myocyte, Ion Channel, and Clinical Translation working groups.
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. Label-free contractility and extracellular field potential recordings of stem cell-derived cardiomyocytes (iPSC-CMs) is also available in our portfolio. 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.
Results of Phase I Studies
The Ion Channel Work Group finalized its phase I study in 2017. Besides further external sites, Nanion Technologies in Germany, USA and Japan participated with the Patchliner and the SyncroPatch 384PE in this study.
The image on the left hand side displays the results of the blocking effect of 12 compounds on hERG.
The results are in good agreement with manual patch clamp data (Crumb et al., 2016).
Nanion's products in CiPA workstreams
SyncroPatch 384i - Patch clamp meets HTS
The SyncroPatch 384i is a high throughput patch clamp instrument recording from up to 384 cells simultaneously. The SyncroPatch 384i is the highest throughput patch clamp instrument on the market with giga-seal data quality. The SyncroPatch 384/768PE and the new system SyncroPatch 384i are used for CiPA ion channel working group studies.
Request the CiPA assay protocol for the SyncroPatch 384i here.
Patchliner - Versatile and sophisticated
The Patchliner is a fully automated planar patch clamp instrument recording from up to 8 cells simultaneously. With its vast experimental freedom and gigaseal data quality, the Patchliner is one of the most versatile patch clamp instruments on the market.
The Patchliner is used for CiPA ion channel working group studies.
Request the CiPA assay protocol for the Patchliner here.
CardioExcyte 96 - Combined contractility, electrophysiology and cell viability
The CardioExcyte 96 is a hybrid system recording both contractility and electrophysiology of intact cardiomyocyte networks. In addition, the base impedance is continuously and automatically monitored as a measure of acute and chronic cell activity. No subtleties of cytotoxic responses are missed, this includes non-contractile cell types such as hepatocyte-like cells or cancer cells as well as contractile cardiac cells. Impedance and extracellular field potential measurements are performed at high resolution, are non-invasive and label-free. The CardioExcyte 96 is a fully automated device, recording from 96 wells at a time.
The CardioExcyte 96 is used for CiPA myocyte working group studies.
Request the CiPA assay protocol for the CardioExcyte 96 here.
Ion Channel Work Group (ICWG)
ICWG: Description and History
"The Ion Channel Working Group (ICWG), sponsored by the Safety Pharmacology Society (SPS), was established in December 2013. Its primary role is to work in close collaboration with the In Silico Working Group (ISWG) in providing ion channel support for the development of a computer model of the adult human ventricular myocyte, to be used as part of the CiPA initiative in predicting the clinical risk of drug-induced TdP."
"The original remit of the ICWG was: 1) to select key cardiac ion channels to include in the CiPA evaluation; 2) to develop robust, reliable and reproducible voltage clamp protocols required to generate data allowing the training and validation of the in silico model; 3) to define which biophysical and/or pharmacological properties of the channels to study for drug effects in order to optimize the predictivity of the model (e.g., potency (IC50), kinetic of block, rate/use/voltage dependence) and; 4) to define the requirements needed to transition the various ion channel protocols from manual to automated high throughput (HT) patch clamp platforms, in order to adapt to the screening environment present in most pharmaceutical companies."
Selected recombinant human channels: "IKr (hERG), ICa (L-type; Cav1.2), INa (Nav1.5 peak and late current); ITO (Kv4.3); IKs (KCNQ1 + KCNE1), and IK1 (Kir2.1). Following the selection, the ICWG set out to design standardized voltage clamp protocols for each of these channels."
(Source: Journal of Pharmacological and Toxicological Methods "The Comprehensive in Vitro Proarrhythmia Assay (CiPA) initiative — Update on progress. Colatzky et al. (2016) ")
Progress of the Ion Channel Work Group
"Protocols were developed and manual experimental work was completed. The High-Throughput Systems (HTS) studies to evaluate and characterize the automated patch clamp systems is underway. The training compounds have been completed for both manual and automated systems and data analysis initiated. The second phase of the HTS study with the validation compounds is underway. Additional ion channel studies will likely be planned beyond 2017 to further validate the model."
(Source: CiPAproject webpage "CiPA Workstream Timelines")
Data, Applications and Publications on the six Cardiac Ion Channels investigated by the "CiPA Ion Channel Work Group"
- NaV1.5 - Sodium Voltage-gated Channel Alpha Subunit 5
- CaV1.2 - voltage-dependent, L type, alpha 1C subunit calcium channel
- KV4.3 - Shal Related Potassium Channel Member 3
- KV7.1 - KVLQT1 - KQT Related Potassium Channel Member 1
- Kir2.1 - Potassium Voltage-Gated Channel Subfamily J Member 2
- hERG - KV11.1 - Erg Related Potassium Channel Member 2
Myocyte Work Group (MWG)
MWG: Description and History
The role of human cardiac stem cell derived cardiomyocytes (hSC-CMs) within the CiPA paradigm is to confirm in silico reconstructions of the electrophysiologic effects of drugs. This will be accomplished by evaluating the acute effects of drugs on the electrical activity of hSC-CM's using higher throughput approaches that enable more comprehensive and robust assessments earlier in the drug discovery process. Typical techniques involved include assessing changes in the extracellular field potentials of spontaneously active hSC-CMs using multielectrode array (MEA) platforms, or changes in the action potential configuration recorded optically using voltage-sensing dyes (VSD)."
"A pilot study was conducted by the Health and Environmental Sciences Institute (HESI) Cardiac Safety Committee Myocyte Subteam to evaluate reproducibility and variability of electrophysiologic responses across cells, platforms and volunteer study sites for 8 compounds, Mexiletine, Nifedipine, E-4031, JNJ-303, Flecanide, Moxifloxacin, Quinidine and Ranolazine. Overall, most sites detected changes in repolarization consistent with clinical findings, with the greatest source of variability attributed to study site."
"More recently, the HESI Myocyte Subteam was awarded a Broad Area Announcement Grant from the FDA to extend the pilot study to a larger set of 28 compounds categorized according to high, intermediate, and low/no risk of proarrhythmia based on clinical findings. The effects of these CiPA reference standards will be evaluated by a core group in this Phase II Validation study across four MEA and two VSO technology platforms using two commercially viable hSC-CM preparations." Results will be compared with prospective in silico reconstructions (based on voltage clamp studies) and published studies employing hSC-CMs from non-core laboratories and consortia for the same 28 compounds."
(Source: Journal of Pharmacological and Toxicological Methods "The Comprehensive in Vitro Proarrhythmia Assay (CiPA) initiative — Update on progress. Colatzky et al. (2016) ")
Progress of the Myocyte Work Group
The publication detailing the results of both the Pilot and Validation Studies are available online. The review on best practices is available here.
(Source: CiPAproject webpage "CiPA Workstream Timelines")
Nanion for CiPA: