According to ICH E6, how is a clinical trial defined?

The definition of a clinical trial according to ICH E6 is a systematic investigation evaluating the safety and effectiveness of a medicinal product. This definition emphasizes the structured and methodical approach inherent in clinical trials, which are essential for obtaining comprehensive data about how a medicinal product performs in human subjects.

Clinical trials are designed not just to gather initial data on a new treatment but to rigorously assess both its safety (the likelihood of harmful effects) and its efficacy (how well it works). This dual evaluation is critical because it informs regulatory bodies, healthcare professionals, and patients about the potential benefits and risks of the drug.

In comparison, other options do not fully encompass the formal and comprehensive nature of clinical trials. While evaluating a drug's market potential, such as stated in the first option, could be a part of the broader context of drug development, it does not capture the specific aim of a clinical trial to assess safety and efficacy. The third option, focusing solely on regulatory approval, narrows the purpose of a clinical trial too much, while the last option suggests a less rigorous approach by implying that clinical trials are merely a collection of case studies, which lack the structured methodology and scientific rigor necessary for formal clinical research.