06.11.2020: Publication Alert - Reliable identification of cardiac liability in drug discovery
Reliable identification of cardiac liability in drug discovery using automated patch clamp: Benchmarking best practices and calibration standards for improved proarrhythmic assessment
The use of automated patch clamp (APC) electrophysiology in cardiac safety screening has increased over the years, and APC is now an established and accepted technique in most, if not all, safety testing laboratories. Since the introduction of the ICH S7B non-clinical guidance in November 2005 which requires all new drugs to be tested for activity on the IKr current carried by hERG expressed in recombinant cell lines using the patch-clamp technique, very few drugs have been withdrawn from the market due to pro-arrhythmic complications. APC has become the major workhorse in safety testing laboratories and is now considered to be the gold standard. Furthermore, with the introduction of the comprehensive in vitro pro-arrhythmia assay (CiPA) which recommends expanding electrophysiological recordings to include other cardiac ion channels, APC will continue to play a major role in cardiac safety testing. Recently, a large study comparing the results of a set of standard compounds tested on different instruments at different sites has been published which highlights the need for standardized protocols for reliable results, for example, for hERG recordings.
We have undertaken a study to identify key parameters that can affect IC50 values of compounds acting on hERG using the medium and high throughput APC systems, Patchliner, SyncroPatch 384PE and SyncroPatch 384i. Effects of experimental parameters such as voltage protocol, incubation time, labware, compound storage time and replicate number on IC50 values of a set of CiPA compounds will be presented and recommendations for best practices for hERG measurements using APC is provided. Furthermore, as outlined in the 2020 Best Practice Consideration for In vitro Studies, ‘The concentration of compound to which the cells were exposed should be verified by applying a validated analytical method to the solution collected from the cell chamber’ in patch clamp studies. Nanion has implemented a new procedure that enables sample collection from used wells from the NPC-384 chips and this will be described.
1. Kramer J, Himmel HM, Lindqvist A, et al. (2020) Cross-site and cross-platform variability of automated patch clamp assessments of drug effects on human cardiac currents in recombinant cells. Nat Sci Reports 10:5627. doi: 10.1038/s41598-020-62344-w
2. (2020) ICH E14 / S7B Implementation Working Group: Clinical and Nonclinical Evaluation of QT / QTc Interval Prolongation and Proarrhythmic Potential Questions and Answers. https://database.ich.org/sites/default/files/ICH_E14-S7B_QAs_Step2_2020_0827_0.pdf. Accessed 22 Sep 2020