According to Scott Gottlieb, M.D., FDA Commissioner, one of the most promising ways to make drug development more efficient is by developing the science around innovative approaches to the design of clinical trials. Here Gottlieb introduces two new Guidance documents intended to do this – “Hematologic Malignancies: Regulatory Considerations for Use of Minimal Residual Disease in Development of Drug and Biological Products for Treatment” and “Developing Targeted Therapies in Low-Frequency Molecular Subsets of a Disease.” (