The views expressed in this paper are those of the author and do not necessarily reflect the views or opinions of any regulatory authority or any of the regulatory advisory bodies.
Drug-induced QT interval prolongation: does ethnicity of the thorough QT study population matter?
Article first published online: 10 JAN 2013
© 2012 The Author. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society
British Journal of Clinical Pharmacology
Volume 75, Issue 2, pages 347–358, February 2013
How to Cite
Shah, R. R. (2013), Drug-induced QT interval prolongation: does ethnicity of the thorough QT study population matter?. British Journal of Clinical Pharmacology, 75: 347–358. doi: 10.1111/j.1365-2125.2012.04415.x
- Issue published online: 10 JAN 2013
- Article first published online: 10 JAN 2013
- Accepted manuscript online: 7 AUG 2012 10:46PM EST
- Manuscript Accepted: 2 AUG 2012
- Manuscript Received: 3 MAY 2012
- response analysis;
- thorough QT study
Inter-ethnic differences in drug responses have been well documented. Drug-induced QT interval prolongation is a major safety concern and therefore, regulatory authorities recommend a clinical thorough QT study (TQT) to investigate new drugs for their QT-prolonging potential. A positive study, determined by breach of a preset regulatory threshold, significantly influences late phase clinical trials by requiring intense ECG monitoring. A few studies that are currently available, although not statistically conclusive at present, question the assumption that ethnicity of the study population may not influence the outcome of a TQT study. Collective consideration of available pharmacogenetic and clinical information suggests that there may be inter-ethnic differences in QT-prolonging effects of drugs and that Caucasians may be more sensitive than other populations. The information also suggest s that (a) these differences may depend on the QT-prolonging potency of the drug and (b) exposure–response (E–R) analysis may be more sensitive than simple changes in QTc interval in unmasking this difference. If the QT response in Caucasians is generally found to be more intense than in non-Caucasians, there may be significant regulatory implications for domestic acceptance of data from a TQT study conducted in foreign populations. However, each drug will warrant an individual consideration when extrapolating the results of a TQT studyfrom one ethnic population to another and the ultimate clinical relevance of any difference. Further adequately designed and powered studies, investigating the pharmacologic properties and E–R relationships of additional drugs with different potencies, are needed in Caucasians, Oriental/Asian and African populations before firm conclusions can be drawn.