Independent data monitoring committees: an update and overview.

An independent data monitoring committee׳s (IDMC's) duty is to ensure that the interests of the patients entered in the trial are being well served (i.e., the risk-benefit ratio is appropriate) and that the scientific integrity of the trial is maintained during the interim between trial initiation and trial completion. Industry sponsors form IDMCs to ensure an independent assessment to assure that the study participants are not exposed to unnecessary or unreasonable risks because of their trial participation and to ensure that the study is being conducted according to highest scientific and ethical standards. IDMCs are needed to analyze interim data for large randomized studies, in particular those that involve multiple sites and important clinical end points such as survival or disease progression. Ethical principles mandate that clinical trials begin with uncertainty as to which treatment is better (clinical equipoise). This uncertainty should be maintained during study conduct and analysis unless there are compelling data that emerge during the conduct of the trial. Group sequential statistical designs offer a mechanism to consider terminating a trial early and the results made public if the interim data become sufficiently compelling. Interim monitoring of safety and efficacy data is an integral part of modern clinical trials.