This NOFO supports applications to develop and implement investigator-initiated single site clinical trials including efficacy, comparative effectiveness, pragmatic and/or implementation research clinical trials. Trials using innovative designs such as platform trials, adaptive, and Bayesian designs are encouraged. These trials may include ones that test different therapeutic, behavioral, and/or prevention strategies. Trials for which this NOFO applies must be relevant to the research mission of the NHLBI and meet the NIH definition of a clinical trial (see NOT-OD-15-015).