Data and safety monitoring boards: some enduring questions.

Data Safety and Monitoring Boards (DSMBs) have been referred to as a "growth industry," and this trend continues to be fueled by recent FDA guidance and the NIH's requirement that DSMBs be employed in virtually all phase III clinical trials. The widening role of DSMBs has been sporadically questioned on ethical grounds, but growth has continued, despite the fact that many of the questions endure, unanswered, save for repeated references to safeguarding the scientific integrity of trials. This may be about to change.