Cardiac Arrhythmia Assessment in Phase IV Clinical Studies

Abstract

The safety and efficacy of a pharmaceutical product is evaluated during product development; however, safety surveillance must continue after marketing. One principal tool for postmarketing safety surveillance is the analysis of spontaneous (nontrial based) adverse reaction reports. Formal studies, either experimental or observational in design, are other means to further assess an approved product’s safety. Although the term “phase IV studies” is used to describe studies conducted after a drug is marketed, this term does not reflect a particular study design. Epidemiologic cohort studies conducted in administrative databases are examples of study designs used to examine the safety of new products. Other powerful study designs, such as large and simplified clinical trials (SCTs), may also provide safety and effectiveness data to supplement pre-approval information. The purpose of this chapter is to describe limitations of the drug approval process and to discuss post-marketing methods useful for assessing cardiac arrhythmias, particularly as related to QTc interval prolongation.