Ethical issues during the conduct of clinical trials.

While the focus of ethical clinical trial conduct has been on protocol review in advance of the research, there has been a recent emphasis on monitoring subject welfare during the conduct of research. The ethical conduct of a clinical trial does not end with the formulation of study design or the obtainment of a signature on the informed consent form. This article defines and describes the necessary monitoring responsibilities to ensure the adequate protection of the rights and welfare of human subjects and the four parties who share such responsibilities: the institutional review board, the data monitoring committee (or the data safety and monitoring board), the sponsor, and the investigator. This article also reviews the numerous challenges associated with monitoring--such as overlapping responsibilities, communication gaps, and lack of standards--and attempts to provide recommendations to address some of these issues.