Focus on issues in measuring and interpreting changes in the QTc interval duration
University of Pennsylvania, eResearch Technology, Philadelphia, U.S.A.
* Correspondence: Joel Morganroth, MD, Clinical Professor of Medicine, University of Pennsylvania, eResearch Technology, 30 S. 17th Street, Philadelphia, PA 19103, U.S.A.
Abstract
Subtle changes on the ECG associated with reports of sudden death produced by non-cardiac drugs, has forced regulatory authorities to be extremely sensitive to ECG findings in drug development programmes. These concerns require pharmaceutical sponsors to re-evaluate their preclinical screening programmes and to consider risk-benefit analyses of continuing a drug's development depending on the electrophysiological effects uncovered. Furthermore, during clinical testing, the non-rigorous, site-specific, and largely uncontrolled methods for performing and analysing ECGs that are currently practised should now be reconsidered. Current methods, which lack standards for interpretation, and yield poor quality data, increase the subsequent risk of false positive or false negative ECG safety results. False positive data may result in a drug not receiving regulatory approval (or the sponsor having to perform additional expensive clinical trials or retrospective reviews of existing ECG data). More worrisome are false negative studies which result in approval followed by unexpected cardiac toxicity (when the drug is taken by a larger and uncontrolled patient population) and ultimately withdrawal from the market. The economic consequences of either of these outcomes are not acceptable. Core ECG laboratories, with cardiovascular expertise, state-of-the-art information management technologies, and ECG reading systems, which are validated, quality assured, and constantly audited, can cost-effectively manage a product's entire ECG safety programme. Finally, with all ECG data residing in one unified database, the validation and integration of clinical research data can be completed more rapidly with consequent dramatic reductions in the time required to prepare an NDA and ultimately gain regulatory approval.
Key Words: QTc interval • ECG • drug development • drug safety • clinical trial design
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