Data and Safety Monitoring Boards (DSMBs) have become an increasingly common feature of clinical trial oversight, yet a paucity of legal or ethical frameworks govern these Boards' composition or operation, or their relationship with other actors with monitoring responsibilities. This paper argues that prevailing structural gaps are impeding harmonized systems for monitoring the ongoing ethical acceptability of clinical trials. Particular tensions stem from DSMBs' sweeping discretion in deciding whether and when to recommend that a trial should be terminated or amended based on safety and efficacy information. This discretion becomes especially challenging in light of DSMBs' monopoly over emerging trial data, which prevents Institutional Review Boards, sponsors, and investigators from participating in certain pivotal and ethically charged decisions. To address these disconnects, I advocate for strengthened pre-trial and post-trial communication in addition to innovative strategies to support DSMB decision making through the life of a trial.
Keywords: Data Safety and Monitoring Boards; Institutional Review Board; clinical trials; data monitoring; human subjects protection; research ethics.