Efficacy considerations for U.S. Food and Drug Administration approval of diagnostic radiopharmaceuticals.

The safety and efficacy expectations for U.S. Food and Drug Administration (FDA) approval of diagnostic radiopharmaceuticals (DRs) are described in laws that broadly apply to all prescription drugs and biologic products. These laws also outline efficacy expectations that are unique for DRs. The FDA regulations and guidance documents elaborate on DR efficacy expectations for clinical uses of the drugs, such as the delineation of anatomy, the characterization of a physiologic process, or the diagnosis of disease. As described in the FDA regulations, the approval of a DR necessitates that the imaging drug has the ability to provide clinically useful information. Here we cite approved DRs to illustrate how the imaging performance of the drugs was characterized in clinical studies and the clinical usefulness of the imaging information described in drug labels.