Development of drugs that alter ventricular repolarization

Atrial Fibrillation in COVID-19: From Epidemiological Association to Pharmacological Implications

Coronavirus disease 2019 (COVID-19) outbreak is a public health emergency of international concerns because of a highly pathogenic human coronavirus (HCoV), actually named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite much emerging data about the epidemiological association between cardiovascular diseases and COVID-19, little is still known about atrial fibrillation and its optimal management in this clinical contest. The aim of our review is to describe the pharmacological interactions between cardiovascular drugs more commonly used in atrial fibrillation management and experimental COVID-19 therapies, based on EU and US summaries of product characteristics.

Dealing with global safety issues : was the response to QT-liability of non-cardiac drugs well coordinated?

Drug-induced torsade de pointes (TdP) is a potentially fatal iatrogenic entity. Its reporting rate in association with non-cardiac drugs increased exponentially from the early 1990s and was associated with an increasing number of new non-cardiac drugs whose proarrhythmic liability was not appreciated pre-marketing. This epidemic provoked a comprehensive global response from drug regulators, drug developers and academia, which resulted in stabilization of the reporting rate of TdP. This commentary reviews the chronology and nature of, and the reasons for, this response, examines its adequacy, and proposes future strategies for dealing with such iatrogenic epidemics more effectively. It is concluded that the response was piecemeal and lacked direction. No one entity was responsible, with the result that important contributions from regulators, industry and academia lacked coordination. While the process of dealing with QT crisis seemed to have worked reasonably well in this instance, it does not seem wise to expect the next crisis in drug development to be managed as well. Future crises will need better management and the challenge is to implement a system set up to respond globally and efficiently to a perceived drug-related hazard. In this regard, we discuss the roles of new tools the legislation has provided to the regulators and the value of an integrated expert assessment of all pre-approval data that may signal a potential safety issue in the postmarketing period. We also discuss the roles of other bodies such as the WHO Collaborating Centre for International Drug Monitoring, CIOMS and the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH).

Detection of proarrhythmia in the female rabbit heart: blinded validation

INTRODUCTION

Reliable detection of drug-induced proarrhythmia, especially the potential for polymorphic ventricular tachycardia, is of great importance in the development of new compounds that are safe for the heart and was evaluated in a blinded study.

METHODS AND RESULTS

In 142 female rabbits, the monophasic action potential was used to determine intraventricular conduction, action potential duration (APD), triangulation (APD30 to APD90), reverse use-dependence, instability and presence of chaotic behavior, early afterdepolarizations, torsades de pointes (TdP), and ventricular fibrillation. In addition, 31 coded drugs were tested in a blinded fashion in another 150 hearts. Prototype cardiovascular agents [quinidine (IA), lidocaine (IB), flecainide (IC), propranolol (II), sotalol (IIIB), amiodarone (IIIAB) and verapamil (IV)] were correctly characterized in terms of their effects upon conduction and APD. Agents documented in clinical practice to have proarrhythmic potential (droperidol, sotalol, mibefradil, bepridil, lidoflazine, ketanserin, sertindole, terfenadine, haloperidol, astemizole, cisapride, ziprasidone, lubeluzole, dofetilide, quinidine, ibutilide) were identified as such. Pimozide is reported to rarely produce TdP and was also found to elicit Class III action with few adverse effects. Equally important, agents believed not to be proarrhythmic (two solvents, atenolol, propranolol, fenoximone, cetirizine, verapamil, sildenafil, lidocaine, diltiazem) were identified as having no proarrhythmic activity.

CONCLUSION

The SCREENIT method properly characterized and quantified prototype cardiovascular drugs and correctly identified proarrhythmic noncardiovascular agents of various mechanisms, but it did not produce false-positive results.