Every protective order I've ever seen has a provision at the end requiring the parties to return or (more likely) destroy any confidential information (with some limited exceptions) from the other party when the case is over. It's generally not a contentious paragraph.
Judge Fallon, however, dealt with a discovery dispute on this issue, that I was surprised had never come up before -- what happens when there are multiple unrelated defendants, as in ANDA cases? Do you destroy the documents when the relevant defendant drops out of the case, or can you keep them until the whole consolidated mess is over and done with?
Per Judge Fallon, the answer is you get to …