Perhaps someone with more FDA expertise than I will help out here.
It is my layman's understanding that an approved drug for one indication may be prescribed by a doc for any indication. However, the docs are looking over their shoulder at malpractice suits, so are loath to depart from the label, UNLESS, there has been at least one peer-reviewed study showing a benefit for another indication. We already have that with CD and soon will have it with RA.
It is also my understanding that a drug co can market to docs (not the public) off-label use provided one peer-reviewed study on the second indication has been published. We are already there with CD, which is pending before Europe based on published trial results.
Any help here on off-label use will be appreciated.