Shalom Bresticker Feb 1, 2018:

In https://www.proz.com/kudoz/English/medical_pharmaceuticals/3... a responder wrote,

"Marketed use means drug use after it has been registered and allowed for retail."

So that would contrast the use after approval to the use in clinical trials, for example.

In addition, it appears to me that it also described a use that has been approved by the regulatory body, as opposed to using it in an unapproved way.