Defining Treatment-Emergent Adverse Events with the Medical Dictionary for Regulatory Activities (MedDRA)

Summaries of safety data collected in a clinical trial typically include an analysis of the crude rate of treatment-emergent signs and symptoms. This paper outlines the issues in defining treatment-emergent events and discusses the impact of choosing different methodologies for event classification and data collection. It also relates these issues to the adoption of the Medical Dictionary for Regulatory Activities (MedDRA) as the standard coding dictionary for regulatory reports. While pharmaceutical companies are addressing the conversion of their existing dictionary system to MedDRA, it may be beneficial to address the issue of defining treatment-emergent so that any changes can be incorporated at the same time. Examples and recommendations are provided.