Drug labeling is intended to provide full prescribing information for a drug and should include all clinical indications for which adequate data are available to establish the drug's safety and effectiveness. In order for a new indication to be added to the label of an already approved drug, the sponsor, usually the manufacturer must file an SNDA (Supplemental New Drug Application) with FDA. An SNDA is reviewed in much the same manner as any New Drug Application.

FDA recently published a guidance for industry entitled, "A New Use Initiative - FDA Approval of New Cancer Treatment Uses for Marketed Drug and Biological Products," to explore the steps the Agency can take to improve the process for approving promising new uses for drug and biological products. Even though it has not been fully implemented, the Agency already is utilizing the procedures in many instances. This new initiative is based on FDA's belief that when products approved for one use are shown to be safe and effective for treating other conditions, those new uses should be added to drug labeling as simply and quickly as possible.