A DMC or DSMB is often a requirement for clinical trials. The DMC is an independent group of experts that conduct a periodic review of accumulated data during a clinical trial. The primary purpose of the DMC is to report early evidence of benefit or harm, taking into account the safety of the participants and the integrity and validity of the data. The key to an effective DMC is truly independent members. DMC members should not have conflicts of interest that may compromise an unbiased review and recommendation to the sponsor.