Importance of GLP hERG testing: Ensure data regarding a drug’s potential to cause cardiac arrhythmias is reliable, giving confidence that it can be used in regulatory decision making

The hERG gene encodes a potassium ion channel that is essential for repolarizing the cardiac action potential. Inhibition of this channel can prolong the QT interval on an electrocardiogram (ECG), leading to a condition called Torsades de Pointes (TdP), a potentially fatal arrhythmia.

Due to its role in cardiac safety, assessing the interaction of drug candidates with the hERG channel is a critical step in drug development. Compounds that significantly inhibit the hERG channel are considered high-risk for causing QT prolongation and potentially TdP.

As such, GLP (Good Laboratory Practice) hERG testing is required for most novel compounds when filing an IND submission, with recent updates to ICH E14 /S7B guidelines clearly defined the protocol and reporting requirements for such studies.

ICH guidelines on hERG testing

The ICH S7B² (nonclinical evaluation of the potential for delayed ventricular repolarization (QT interval prolongation) by human pharmaceuticals) guideline addresses the nonclinical testing requirements related to QT interval prolongation. It emphasizes the need to assess a drug’s potential to delay ventricular repolarization, which is primarily conducted via in vitro studies using the hERG channel.

The ICH E14³ (clinical evaluation of QT/QTc interval prolongation and proarrhythmic potential for non-antiarrhythmic drugs) guideline deals with clinical implications. It provides guidance on the design of clinical studies to assess the proarrhythmic potential of a drug by monitoring QT/QTc intervals during clinical trials.

GLP hERG testing

In the context of hERG testing, GLP compliance ensures that the data generated from hERG assays are accurate and reproducible, providing a reliable basis for assessing the cardiac safety of a drug candidate. This is crucial for regulatory submissions, as non-GLP studies might not be accepted by regulatory authorities.

Integration in drug development

• Early-stage screening: hERG testing is often conducted in the early stages of drug development to identify potential liabilities and avoid advancing compounds with a high risk of causing QT prolongation.
• Regulatory submission: Data from GLP-compliant hERG studies are included in the nonclinical safety sections of regulatory submissions, such as Investigational New Drug (IND) applications, New Drug Applications (NDA), and Marketing Authorization Applications (MAA).
• Mitigating risk: If a compound shows hERG inhibition, additional studies, including in vivo models and clinical trials, are necessary to assess the overall risk and explore strategies to mitigate this risk, such as dose adjustments or structural modifications of the compound.

GLP testing services

GLP hERG testing is a critical component of the safety assessment process for new pharmaceuticals, ensuring that data regarding a drug’s potential to cause cardiac arrhythmias is reliable and can be confidently used in regulatory decision-making as per ICH guidelines.

Metrion provides specialist GLP testing services against hERG using the conventional whole-cell patch-clamp technique. Our services have been audited and approved by the UK Medicines and Healthcare products Regulatory Agency (MHRA) and are performed in accordance with the Food and Drug Administration (FDA) best practice guidelines.

Useful reading

Metrion are co-author of a paper in which GLP hERG data were generated for the three reference compounds using ICH best practices in order to understand intra and inter laboratory variability in the data and to assess a suitable hERG safety margin under these conditions.⁴

1. https://www.ich.org/page/ich-guidelines
2. https://database.ich.org/sites/default/files/S7B_Guideline.pdf
3. https://database.ich.org/sites/default/files/E14_Guideline.pdf
4. Derek J. Leishman, Jessica Brimecombe, William Crumb, Simon Hebeisen, Steve Jenkinson, Peter J. Kilfoil, Hiroshi Matsukawa, Karim Melliti, Yusheng Qu, Supporting an integrated QTc risk assessment using the hERG margin distributions for three positive control agents derived from multiple laboratories and on multiple occasions., Journal of Pharmacological and Toxicological Methods, Volume 128, 2024, 107524, ISSN 1056-8719, https://doi.org/10.1016/j.vascn.2024.107524.